The correct answer is 1.

This trauma patient has signs and symptoms suggestive of a posterior urethral injury. Urethral injuries can be classified broadly based on anatomic location. Injury to the anterior urethra, the portion of the urethra distal to the urogenital diaphragm, most commonly results from blunt trauma to the perineum (straddle injuries) or instrumentation of the urethra. Findings include perineal tenderness or hematoma, a normal prostate, and bleeding from the urethra. Patients may not complain of inability to urinate, and delayed presentations may be complicated by sepsis secondary to extravasation of urine into the scrotum, perineum and/or abdominal wall. The posterior urethra consists of the prostatic and membranous urethra. Posterior urethral injuries are commonly associated with fractures of the pelvis. Patients classically complain of suprapubic pain and an inability to void following major trauma. Examination will show blood at the urethral meatus, a high-riding prostate due to displacement of the prostate by a pelvic hematoma, and scrotal hematoma, in addition to signs and symptoms of pelvic fracture.

(Choices 2 & 3) Bladder injury can present with gross hematuria and may cause difficulty with urination but would not cause a distended bladder. Intraperitoneal bladder rupture would cause peritoneal signs.

(Choice 4) Penile fracture typically occurs secondary to trauma to the erect penis during intercourse. Patients will describe a snapping sound that is followed by pain, and deviation of the axis of the shaft due to hematoma formation.

(Choice 5) Patients with traumatic renal injuries present with hematuria, abdominal distention, flank pain and ecchymoses. There may also be a palpable flank mass.

The correct answer is 3.

The double bubble sign with a little gas beyond is highly suggestive. The diagnosis must be promptly confirmed (by barium enema or contrast study from above) so that emergency surgery can be performed before the bowel dies twisted on its vascular pedicle. This condition can be present at birth or it can also show up later, as in this example.

(Choice 1) is suggested by the age (it presents at 3 weeks). However, the vomiting would have been projectile and free of bile, and x-ray films would have shown only gastric distention.

(Choice 2) shows up at birth, and the x-ray films show multiple air fluid levels.

(Choice 4) is also obvious earlier in life, but the infant would have cystic fibrosis, an unused microcolon, and inspissated meconium in the ileum giving a ground glass appearance in the x-ray films.

(Choice 5) occurs in the premature infant when first fed.

The correct answer is 1.

Esophageal perforation is a condition that causes sudden-onset, severe, unrelenting pain that is located retrosternally or in the neck, back or abdomen. The pain is often exacerbated by swallowing. Because of these nonspecific presenting symptoms, the differential diagnosis at the time of presentation often includes myocardial infarction, dissecting aortic aneurysm, pulmonary embolism or surgical abdomen. More specific signs of esophageal perforation include subcutaneous emphysema in the neck or a characteristic crunching sound on auscultation of the heart due to mediastinal emphysema (Hamman’s sign). Chest x-ray is rarely diagnostic; findings may include air in the paraspinal muscles, a widened mediastinum, pneumomediastinum, pneumothorax or pleural effusions. The diagnosis of esophageal perforation is confirmed with a Gastrografin esophagogram, which will demonstrate contrast leakage at the site of perforation. Patients with this condition require immediate broad-spectrum antibiotic therapy and surgical repair. Esophagitis is a condition that predisposes to esophageal perforation. This particular patient may have pill induced esophagitis secondary to potassium chloride and/or infectious esophagitis secondary to Candidal infection related to his HIV disease.

(Choice 2) Even though barium study is more sensitive for diagnosing small perforations it is not used as first line because of the risk of mediastinal inflammation. Gastrografin is water soluble and less irritating to mediastinum.

(Choice 3) Upper gastrointestinal endoscopy and other types of esophageal instrumentation are the most common cause of esophageal perforation.

(Choice 4) Transesophageal echocardiography is used to image the posterior heart and to examine small valvular vegetations (provides higher resolution than transthoracic echocardiography).

(Choice 5) Bronchoscopy helps to assess the conducting airways for pathology like tumors, hemorrhage, obstructions, trauma or infection.

The correct answer is 3.

The nurse suspects that the patient has idiopathic scoliosis. The school screening test for this disorder is called the Adam’s forward-bending test. By assuming this near 90-degree bent position, abnormal lateral curvature (S or C shape) of the spine is easy to observe. Confirmation is generally made by an imaging study in which the degree of curvature is determined by a geometrical process called the Cobb method. A curvature greater than 2s degrees is considered significant, greater than 4s-s0 degrees is considered severe.

Scoliosis is most commonly idiopathic and often is first diagnosed in adolescent girls from 10 to 16 years of age. Scoliosis refers to lateral displacement of the spine, while kyphosis refers to forward displacement (e.g., hunchback) of the spine. A third type of unusual spinal shape is called lordosis (aka, sway back); this is not considered pathologic as long as the back remains flexible.

(Choice 1) is a human leukocyte antigen (HLA)-B27-positive arthropathy that is more common in men. Sacroiliitis and fusion of the spine (bamboo spine) are prominent features of this disease. Forward bending of the spinal column becomes increasingly more pronounced as the disease progresses.

(Choice 2) refers to tuberculosis involving the vertebral column.

(Choice 4) does not typically produce spinal abnormalities.

(Choice 5) is associated with kyphoscoliosis; however, cafe au lait spots are likely to be present as well.

The correct answer is 3.

The patient has acute diverticulitis. Herniation of the colonic mucosa through the circular muscles of the colon leads to the formation of diverticula. In Australia, about 95% of these are located in the sigmoid colon, but among Koreans, Japanese, Chinese, and Malaysians, they are twice as likely to form in the ascending colon. In some severely affected individuals, the entire colon may be involved; however, diverticula are not found in the rectum because it has a complete circular layer of muscle. Diverticula usually form due to a lack of roughage in the diet. The high fiber content of typical African and Indian diets makes diverticular disease a rarity in these cultures. When one or more diverticula get inflamed, the term diverticulitis applies. The clinical presentation in diverticulitis is similar to that of acute appendicitis, except that it is on the left side. Pyrexia, malaise, and leukocytosis are features. Sometimes a tender mass may be palpable on rectal examination. Presence of urinary symptoms, such as dysuria, may be a forerunner to the formation of a vesicocolic fistula. In such cases, the patient would develop pneumaturia and pass flatus or even fecal material in the urine. The diagnosis is made on clinical grounds. Computed tomography (CT) confirms the diagnosis and also delineates associated pericolic abscesses. Although very mild cases may be

treated at home with oral antibiotics and a liquid diet, more commonly, acute diverticulitis is treated in a hospital setting with intravenous antibiotics, a combination of cefuroxime and metronidazole. Once the acute attack has resolved, a barium enema and flexible sigmoidoscopy or colonoscopy should be performed. Doing so in the acute phase could result in perforation and peritonitis. Surgery is indicated in approximately 10% of patients. Such surgery is performed during a quiescent period after careful bowel preparation; it consists of a one-stage resection and end-to-end anastomosis. If there is bowel obstruction, a Hartmann’s procedure is performed. If the patient has fecal peritonitis, the options include primary resection and Hartmann’s procedure or, in rare cases, primary resection and anastomosis.

(Choice 1) is incorrect; ulcerative colitis is a nonspecific inflammatory disease that usually affects adults between the ages of 20 and 40. Both sexes are equally affected. In approximately 95% of cases, it commences in the rectum and spreads proximally. In chronic cases, pseudopolyps occur (chronic inflammatory polyps). The sine qua non of this disease is bloody diarrhea and rectal discharge that may be blood-stained or foul smelling. Pain is not an early symptom of the disease. The disease is characterized by exacerbations and remissions. In severe cases, mild-grade fever, tachycardia, and hypoalbuminemia could occur. Other complications include toxic megacolon, perforation, and rarely, severe hemorrhage. Carcinoma can occur in those who develop the disease early in life or if the malady involves the whole colon. Colonoscopy and biopsy have an important role to play in the diagnosis of ulcerative colitis.

(Choice 2) is incorrect. Irritable bowel syndrome (IBS) is the most common gastrointestinal disease seen in clinical practice. It usually begins before the age of 30. Women are twice as likely to suffer from it as are men. Patients with IBS may have psychiatric disorders such as hysteria, obsessive-compulsive disorder, and depression. There are three types of presentation: (a) chronic abdominal pain and constipation (spastic colon), (b) alternating constipation and diarrhea, and (c) chronic painless diarrhea. The patients may also complain of abdominal distention, a feeling of incomplete evacuation, and relief of abdominal pain with evacuation. The diagnosis is based on the Rome criteria and is one of exclusion. Barium enema and colonoscopy are required to exclude inflammatory or neoplastic disease. Treatment includes a high-fiber diet, psyllium extract, and anticholinergics. Psychiatric consultation is indicated in appropriate cases.

(Choice 4) is incorrect; carcinoma of the colon is most commonly seen on the left side. It is usually of the stenosing type. Thus, the predominant symptoms are that of progressive intestinal obstruction. In approximately 15% of cases, diverticular disease and colon carcinoma coexist. Loss of weight, positive occult blood test result, and a falling hematocrit should raise concerns about this possibility. Additional features include change in bowel habit, such as alternating constipation and diarrhea, colicky pain, and tenesmus (need for evacuation), especially if the tumor is located low in the descending colon. In the latter case, patients may pass blood and mucus, mucus being more common in the morning. If a mass is felt on rectal examination, it will not be tender. Double-contrast barium enema is carried out in patients who have such altered bowel habits, and colonoscopy is indicated in those who have bleeding per rectum. Ultrasonography is used to exclude the presence of hepatic metastases, while CT is indicated in patients who have large palpable masses in the abdomen.

(Choice 5) also is incorrect; ischemic colitis results from paucity of blood flow to the colon. The most common location is at the splenic flexure. The patient is usually in the sixth decade of life and has degenerative vascular disease. Rectal bleeding and infrequent colicky abdominal pain and vomiting may precede a dramatic onset. Pain may occur several hours after a meal. The onset is usually abrupt, with severe lower abdominal pain, vomiting, fever, and bleeding per rectum. Tenderness and guarding of the abdomen will be noted, and bowel sounds may be decreased. An arteriogram confirms the diagnosis. Most cases resolve spontaneously. Treatment is supportive. Some of these patients could develop strictures that would require surgery.

The correct answer is 2.

Boerhaave syndrome refers to a full-thickness rupture of the distal thoracic esophagus or stomach and is associated with vomiting or retching. In most cases, this syndrome is associated with alcoholics who have forceful vomiting or retching. However, it is also the most serious complication of bulimia nervosa, an eating disorder associated with binging on excessive amounts of food followed by self-induced vomiting.

(Choices 1,3,4 & 5) Gastroesophageal reflux, tension pneumothorax, gastric ulcer disease, and esophageal cancer all may cause retrosternal pain but are not associated with vomiting and bulimia.

The correct answer is 2.

Synovial fluid analysis is essential in managing monoarticular arthritis because the fluid characteristics dictate treatment. For example, septic arthritis warrants antibiotic therapy and

surgical washout of the joint whereas other types of arthritis can be managed conservatively with painkillers alone. The table below describes the synovial fluid findings in different types of arthritis.

In line with the table above, the indications for surgical washout are: positive Gram stain or culture, glucose 75% neutrophils, or >50,000 leukocytes per mcL.

(Choice 1) Inflammatory synovial fluid of any etiology infected or not, may have high viscosity.

(Choice 3) Negatively birefringent crystals are the hallmark of gouty arthritis. Gout is a highly inflammatory mono- or polyarticular arthritis. It can be treated with NSAIDs, prednisone, colchicine, or intra-articular steroids. Surgical intervention is not required.

(Choice 4) A low synovial fluid leukocyte count is not diagnostic of infection.

(Choice 5) Positive rheumatoid factor in the synovial fluid is suggestive of rheumatoid arthritis. This disease is treated with systemic agents, not local procedures.

The correct answer is 3.

This mechanically ventilated patient has a respiratory quotient (RQ) of 1.05. The RQ is the steady-state ratio of carbon dioxide (C0 2 ) produced to oxygen (0 2 ) consumed per unit time and may be used to make assessments of the metabolism taking place in particular organs or in the body as a whole. In a steady resting state, this ratio depends mainly upon the major fuel being oxidized for ATP production. An RQ close to 1 .0 indicates that carbohydrate is the major nutrient being oxidized. Metabolism of proteins alone yields an RQ of approximately 0 .8 and oxidation of fatty acids alone for ATP production yields an RQ of approximately 0.7. The RQ for a given fuel is calculated by dividing the number of moles of C 0 2 produced by the number of moles of o2 required to oxidize one mole of substrate. An example using glucose is shown below:

C 6 Hi 2 0 6 (glucose)+ 60 2 — » 6C0 2 + 6H 2 0

Thus, the RQ for glucose is 6C0 2 /60 2 = 1.0. Because the body normally utilizes a combination of fuels, the normal full-body steady-state RQ is typically near 0.8. The patient in question has an RQ in excess of 1.0, indicating that carbohydrates are serving as the sole source of fuel and net lipogenesis is occurring. Assessment of the RO is important when attempting to wean patients from mechanical ventilation, as overfeeding, especially with carbohydrates, can cause excessive C0 2 production and make weaning more challenging. This factor is especially important in patients with preexisting lung disease.

(Choice 1) Sepsis is a hypermetabolic, hypercatabolic state wherein both body fat and protein is broken down in addition to glucose being oxidized. For this reason, the RQ in a septic patient is typically less than 10.

(Choice 2) A high protein diet (where amino acid oxidation is the predominant form of ATP production) gives an RQ close to 0 .8.

(Choice 4) If tissue oxygen delivery is adequate to prevent anaerobic metabolism, then the RQ will not be affected by the Fi0 2 . Increased 0 2 delivery to the tissues does not equate with increased 0 2 consumption by the tissues. The RQ is calculated using the amount of 0 2 consumed, which is determined by the difference in the oxygen content of the arterial and venous blood.

(Choice 5) Massive atelectasis could affect respiratory gas exchange and alter blood gases, but once a new steady state is achieved, the RQ value would still depend only upon the nature and proportions of metabolic fuels being oxidized.

The correct answer is 4.

Portacaval shunts are very effective in decreasing the pressure in esophageal varices, and thus controlling bleeding from them. But the penalty paid for that diversion of blood flow is further impairment of liver function. One almost never sees cirrhotic patients come to surgery with normal liver function. And, if they are bleeding at the time, they also have a load of ammonia in the gut that has to be cleared by the liver. With the initial limited function, plus the trauma of surgery and the diversion of portal flow, ammonia (as well as other toxic substances) accumulates in the blood and leads to coma.

(Choice 1) would be relevant in an alcoholic who has been drinking up to the time that some unexpected event necessitates emergency surgery. If the patient comes to the operating room with high levels of alcohol in the blood, one can predict that delirium tremens (DTs) will occur 2 or 3 days later.

(Choice 2) Determination of blood gases is always the first thing to do when unexplained mental deterioration occurs after surgery. Hypoxia is very likely to be the culprit. In this case, however, we do not have an unexplained occurrence, but one rather predictable problem. (Choice 3) Blood glucose comes to mind for the diabetic patient known to use insulin who suddenly goes into coma, or for the unknown patient brought to the emergency department in coma and with no history of what happened to him. Although it is true that hypoglycemia is seen in liver failure, it occurs at the very end of the spectrum, when all other parameters of liver function are grossly deranged.

(Choice 5) Rapid changes in serum sodium can cause coma, such as in the precipitous hyponatremia seen in water intoxication or the hypernatremia of profound dehydration.

Neither of those are likely to occur, however, in the setting of this vignette.

The correct answer is 4.

Conversion to unfractionated heparin infusion is required This is a common scenario encountered in any centre where procedural endoscopy is common. Removal of polyps can result in significant bleeding as the lesions are often well vascularized. Patients on warfarin require their INR to be normalized prior to an attempted procedure. In patients receiving warfarin for indications such as atrial fibrillation, warfarin must be stopped 5 days before the procedure. In patients with metal valves, however, the risk of thrombus formation on the valve during this time is too great, and therefore these patients should ideally be admitted and managed on a heparin infusion pump. This allows close, accurate and rapidly reversible anticoagulation which therefore minimizes the time that the patient’s anticoagulation is below therapeutic levels in the peri-procedure period.

Low-molecular-weight heparin is not appropriate as it needs to be stopped 48 hours prior to the procedure, during which the patient would not be adequately anticoagulated. The echocardiogram is unnecessary, as is the CT pneumocolon. The patient requires an intervention; finding a further poly p on CT will not affect the need for poly pectomy.

The correct answer is 3.

Fever, chills and deep abdominal pain suggest a retroperitoneal abscess. Any form of blunt abdominal trauma can compress the neck and/or body of the pancreas against the vertebral column over which it lies. A pancreatic contusion, crush injury, laceration or transection may result. Abdominal CT scans done early following the traumatic insult may fail to detect a pancreatic injury. Serial CT scans are often required to detect the evolution of the injury (i.e., enlargement of the gland, parenchymal disruption, areas of diminished contrast perfusion and peripancreatic fluid collections). Serum amylase values are nonspecific, and do not assist in the diagnosis of pancreatic trauma. If blunt traumatic pancreatic injury is undetected initially, devitalized tissue or a pseudocyst resulting from such injury can become secondarily infected. A pancreatic abscess is a serious complication with a high mortality. Treatment is by immediate placement of a percutaneous drainage catheter, culture of the drained fluid, and ultimately surgical debridement.

(Choice 1) The spleen is the most commonly injured organ following blunt abdominal trauma. Initial CT would have diagnosed the injury. Delayed splenic rupture would cause acute left upper quadrant abdominal pain and possibly hypotension, but not signs of sepsis, as in this case.

(Choice 2) Agastric perforation would be more likely to occur in penetrating (rather than blunt) trauma. Furthermore, this condition would be evident during the initial presentation as an acute abdomen, with free air under the diaphragm on upright abdominal x-ray studies (or CT scan).

(Choice 4) Small bowel injury is less likely after blunt (as opposed to penetrating) trauma. One exception is the duodenum, which is almost entirely retroperitoneal. This segment of the small bowel is vulnerable to crush injury where it overlies the vertebral bodies. Such injuries may cause duodenal hematoma and obstruction.

(Choice 5) Meckel’s diverticulitis is generally not a direct consequence of blunt abdominal trauma. It may mimic appendicitis by causing anorexia and midabdominal I right lower quadrant pain. Chills and other signs of sepsis typically do not occur.

The correct answer is 4.

The patient in this vignette has a pulsatile abdominal mass and is hypotensive. This patient has a diagnosis of a ruptured abdominal aortic aneurysm (AAA) unless proven otherwise. Ruptured AAAs can present in numerous ways, mimicking various abdominal pathology. The classic presentation is with sudden-onset back pain that may be followed by syncope. When hypotension is present with a pulsatile mass, no further studies are indicated. The patient should be immediately taken to the operating room for an emergent laparotomy for repair of the aneurysm. Mortality with this condition is approximately 50%; early recognition and operative intervention are essential.

(Choice 1) Fast track ultrasound is a newer modality used in trauma. It can make a diagnosis of free abdominal fluid but cannot decipher the origin of the fluid or the damaged organ. It can detect an abdominal aneurysm and is the tool classically used to screen for and monitor AAAs.

(Choices 2 & 3) Laparotomy should not be delayed for any other studies or interventions in cases of ruptured AAA. Both of these studies are very time consuming and expose the patient to intravenous contrast, an intervention that itself is not without risk.

(Choice 5) Resuscitation can be done while the patient is being prepared for surgery. In cases of ruptured AAA, as in trauma, aggressive resuscitation can cause increased hemorrhage. The goal of resuscitation should be to maintain mentation and end organ perfusion without hypertension.

The correct answer is 3.

Ultrasonography is the most sensitive and least expensive method to discriminate between testicular and extratesticular masses. However, a physician should remember to first use a simple transillumination test for such a differential diagnosis. Fluid collections within the vaginal sac transilluminate, whereas testicular masses do not.

(Choice 1) is used to determine the spread of testicular tumors within the abdominal and thoracic cavity, but is of no use in the initial diagnosis of scrotal masses.

(Choice 2) Serum levels of hCG, alpha-fetoprotein, and LDH are important adjunct parameters in the diagnosis and subsequent management of testicular neoplasms. LDH may be elevated in seminomas and nonseminomas, alpha-fetoprotein is elevated in nonseminomas (especially yolk sac tumors), and hCG is elevated in nonseminomas (especially choriocarcinomas).

(Choice 4) is not an adequate diagnostic tool in this case. It may be used in the evaluation of azoospermia related to infertility problems.

(Choice 5) is performed once ultrasonography has established that scrotal enlargement is caused by an intratesticular tumor. This allows the most accurate pathologic diagnosis and appropriate management.

The correct answer is 5.

The spleen is the most commonly injured organ in cases of blunt abdominal trauma. Patients who have suffered a splenic injury classically complain of left upper quadrant pain; rib fracture may frequently accompany splenic injuries. Pain referred to the left shoulder may result from irritation of the left hemidiaphragm by hemorrhage. Patients who present in obvious hemorrhagic shock should undergo immediate laparotomy and splenectomy, but most patients are managed nonoperatively with close ICU monitoring and fluid resuscitation. Some patients who have a hemorrhage but are otherwise hemodynamically stabilized may be candidates for angiography, which can demonstrate the exact site of hemorrhage and be used to treat the hemorrhage by embolization. If a patient being treated with observation experiences hemodynamic instability unresponsive to a 2L saline bolus or otherwise requires a blood transfusion, then laparotomy is indicated for splenorrhaphy or splenectomy. Following splenectomy, patients are at a greater risk of infections by encapsulated organisms such as H. influenzae, S. pneumoniae and N. meningitidis. Appropriate vaccinations should be administered in all post-splenectomy patients.

(Choice 1) Referred shoulder pain associated with abdominal pathology (Kehr sign) results from irritation of the diaphragm, in this case by the bleeding spleen, which causes referred pain in the dermatomal distribution of the phrenic nerve roots ( C3 - C5).

(Choice 2) There is poor correlation between the amount of free fluid in the abdomen and the necessity for surgical intervention.

(Choice 3) Fractured ribs are commonly associated with splenic trauma but are not a determinant of surgical versus non-surgical intervention.

(Choice 4) Though post-splenectomy patients are at a higher risk of infection with capsulated organisms, the unvaccinated status of a patient with splenic trauma does not determine surgical versus non-surgical treatment. In general, splenectomy should be avoided

in all patients as the spleen has important immunologic and hematologic functions.

The correct answer is 3.

This patient has an intracranial bleed, signs of increased intracranial pressure (ICP), and evidence on a CT scan of impending herniation. This patient requires rapid lowering of his ICP. The most rapid method available is hyperventilation to lower PaC0 2 , which leads to decreased cerebral blood flow and ICP.

(Choice 1) is unnecessary since the head CT already showed clear signs of impending herniation. An MR scan adds nothing to the decision analysis and need for immediate therapy.

(Choice 2) is also an appropriate therapy in this case. However, mannitol has an onset of action approximately 90 minutes after dosing, which makes hyperventilation the mainstay of acute therapy.

(Choice 4) is used as a last resort to dramatically lower ICP. In cases of severe emergency, patients are mechanically ventilated and placed in a barbiturate coma so that maximal lowering of ICP can be attained.

(Choice 5) may be appropriate, but not until hyperventilation has begun. Like mannitol, surgical decompression (even as emergent surgery) is not immediate; therefore, therapy needs to be instituted during that interval.

The correct answer is 2.

The history is that of transient ischemic attacks (TIAs), which are most commonly due to an ulcerated plaque at the carotid bifurcation or a stenosis greater than 70% of the lumen. For many years, an arteriogram was the only way to diagnose such lesions, but this invasive study sometimes can precipitate the very same stroke that carotid surgery was designed to prevent. Duplex scanning, a noninvasive alternative, is now available. Many patients can be fully diagnosed and operated on without ever needing an arteriogram. For those in whom the study is inconclusive, an arteriogram is the next step.

(Choice 1) CT scan is our best tool when intracranial bleeding is suspected, but the hallmark of such an event is extremely severe headache heralding the neurologic deficits.

(Choice 3) is indicated if the heart is suspected as the source of emboli. The left carotid (where the bruit is) is the likely source of the problem in this vignette.

(Choice 4) MRI is our choice when brain tumor is suspected. The history would be one of several months of increasingly severe headaches that are worse in the mornings, along with eventual development of projectile vomiting and blurred vision.

(Choice 5) Aortic arch arteriogram is required if there is evidence of involvement of the vertebral arteries (neurologic deficits involving visual cortex and cerebellum), or if less invasive studies do not provide a satisfactory explanation of the symptoms. It would not be the first test performed.

The correct answer is 6.

This patient’s history of motor vehicle accident, abdominal wall ecchymosis, distended abdomen and decreased bowel sounds, is suspicious for blunt abdominal trauma. Furthermore, collapsed neck veins and hypotension indicate hemodynamic instability. In a hemodynamically unstable victim of a motor vehicle accident with suspected blunt abdominal trauma, the appropriate management involves cervical spine immobilization, intravenous hydration and FAST (Focused Assessment with Sonography for Trauma). If hemoperitoneum is identified on ultrasound, the patient should then undergo laparotomy. If ultrasound is inconclusive, then diagnostic peritoneal lavage is indicated.

(Choice 1) The use of laparoscopy in cases of blunt abdominal trauma is debatable and hemodynamic instability is an absolute contraindication to laparoscopy.

(Choice 2) Laparotomy is the appropriate next step in management if ultrasound demonstrates hemoperitoneum. Physicians may also skip straight to laparotomy in extreme cases, such as if the patient cannot be stabilized or has clear evidence of pneumoperitoneum or diaphragmatic rupture.

(Choice 3) Angiography is not a screening procedure for hemoperitoneum. However, if active hemorrhage is identified on a screening study and appears amenable to angiographic embolization, then this procedure may be utilized.

(Choice 4) X-ray films of the abdomen and pelvis would be useful for identifying pelvic, rib, or vertebral fractures. Any such fracture may raise concern for injury of abdominal viscera, but could not definitively identify such a condition.

(Choice 5) ACT scan of the chest would not be appropriate in this patient. His symptoms are more consistent with intraperitoneal bleeding than any thoracic etiology. Furthermore, a CT scan of the chest would cost valuable time in this unstable patient.

The correct answer is 1.

Carpal tunnel syndrome is caused by compression of the median nerve at the level of the wrist. The median nerve supplies sensation to the radial three and a half digits of the hand, as well as innervation of the thenar musculature. Symptoms include numbness and tingling in the fingertips and pain that can awaken the patient at night and that can travel proximally up the arm. Hyperextension of the hand or tapping over the nerve reproduces the findings. There can be sensory loss in the median nerve distribution and muscle weakness in the thumb. (Choice 2) is a median nerve entrapment in the proximal forearm. It is a pure sensory syndrome. The cubital tunnel is a groove in the posteromedial aspect of the elbow that contains the ulnar nerve.

(Choice 3) is an ulnar nerve neuropathy.

(Choice 4) can occur at the wrist in Guyon’s canal. In both of these conditions, patients may complain of numbness in the ulnar one and a half digits and have weakness of the intrinsic muscles.

(Choice 5) is usually caused by repetitive use of the thumb for some activity. Patients have pain and tenderness at the region of the radial styloid.

The correct answer is 4.

The patient has renal adenocarcinoma and hypertension secondary to ectopic production of renin by the tumor. Renal adenocarcinoma is the most common neoplasm of the kidney. It affects men twice as often as women, usually in the sixth to seventh decade of life. The neoplasm arises from renal tubular cells. Smoking is a predisposing factor. The tumor

affects the poles of the kidney, more commonly the upper. Hematuria is the most consistent sign (90%), sometimes associated with colic due to clot formation, followed by a dragging discomfort in the loin (45%), a palpable mass (30%), and fever (20%). “Cannonball” metastases to the lung occur in 60% of cases. Fever is not related to infection but results from chemicals released by the tumor. The tumors can ectopically secrete erythropoietin (leading to secondary polycythemia), parathormone-like peptide (leading to hypercalcemia), renin (leading to hypertension as noted in this case), gonadotropins (leading to feminization or masculinization), and/or cortisol (leading to Cushing syndrome). Serum levels of these hormones should be determined to confirm potentially elevated levels. A plain x-ray of the abdomen may show abnormal calcification in the tumor and distortion of the renal outline. An intravenous pyelogram (IVP) will reveal the mass, and the calyces may be stretched and distorted. Ultrasonography will show if the lesion is solid or cystic, and computed tomography (CT) with enhancement will demonstrate the extent of the lesion, including presence of hilar lymphadenopathy or involvement of the renal vein. Needle aspiration of the mass using CT for needle guidance is usually performed to obtain a histologic diagnosis. Angiograms are rarely done, as CT scans with contrast are adequate. Occasionally, an inferior venacavagram is indicated to establish extent of inferior vena caval involvement by the tumor. Radical nephrectomy is the treatment of choice if the tumor is confined to the kidney. The presence or absence of the renal vein or capsular invasion affects overall survival; 45% of patients without renal vein or capsular invasion achieve a 5-year survival, as opposed to 15%-30% of those with invasion. Adenocarcinoma of the kidney does not respond well to radiotherapy or conventional chemotherapy.

(Choice 1) Although the kidney is the most common extrapulmonary site for tuberculosis (TB), is incorrect; the homogeneous nodular masses in the lung go against this diagnosis. Furthermore, renal tuberculosis usually occurs between the ages of 20 and 40. Other properties of renal TB include that it is 50% more likely to occur in men than in women, urinary frequency is the most common and earliest symptom, and the urine remains negative for bacteria in the early stages. Dysuria sets in when the patient develops cystitis. Hematuria occurs in less than 5% of cases, and it is very uncommon to be able to palpate a renal mass in TB of the kidney.

(Choice 2) Transitional cell carcinomas of the bladder usually involve the renal pelvis and produce obstruction. They are not as common as renal cell adenocarcinoma.

(Choice 3) is not multifocal, and metastasis to the kidney is rare.

The correct answer is 3.

Idiopathic thrombocytopenic purpura (ITP) is an immune condition involving antiplatelet antibodies that is most commonly seen in children younger than the age of 6 years and in women in their thirties. In children, ITP is typically self-limiting, and strict bedrest with avoidance of contact sports is recommended. The spleen is the source of the IgG specific for platelets and the site of the phagocytosis of the coated platelets. Signs and symptoms of ITP include bleeding following minor trauma, easy bruising, mucosal bleeding, and petechiae. In adults, the initial treatment includes prednisone 1 mg/kg/day, but only 25% of patients sustain their platelet levels after steroid treatment alone. In those who do not achieve a sustained response to steroid therapy, MG is also given. When a patient fails to respond to these medical therapies, a splenectomy is indicated. Splenectomy is successful in 85% of cases. If ITP recurs after splenectomy, it may be due to the presence of an accessory spleen. Using a technetium-99 colloid scan or infusion of indium-111-labeled platelets, accessory spleens can be localized.

(Choice 1) Outpatient follow-up for a patient with severe thrombocytopenia is inappropriate and risks life-threatening complications such as spontaneous intracranial bleeding.

(Choice 2) Prednisone therapy is an option but 6 months of unmonitored therapy is not indicated.

(Choice 4) A radiolabeled study is used to localize remaining splenic tissue (accessory spleens) following splenectomy. It is not indicated prior to splenectomy.

(Choice 5) The spleen will continue to make antibodies to platelets, and the transfused platelets will eventually be destroyed.

The correct answer is 3.

This patient presents with symptoms and signs suggestive of meniscal injury. The episode of injury occurred one month ago, when acute pain and swelling were present. The current symptoms suggest ‘locking’, a phenomenon that is due to impaired extension of the knee. In addition to the patient’s history, a positive McMurray sign is present (popping sound on passive flexion/extension of the joint), which is specific for meniscal injury. The mechanical symptoms have persisted for one month after the injury, and have impaired the activities of the patient; therefore, further evaluation is necessary. It is reasonable to do an arthroscopy or MRI to confirm the diagnosis, and evaluate the extent of the injury. Surgery (arthroscopic or open) is usually necessary to correct the problem.

(Choice 1) A bone scan will not be informative in this case.

(Choice 2) Intraarticular steroid injections can be used in patients with secondary meniscal injury due to degenerative joint disease.

(Choice 5) Rest and NSAIDs are used as an initial conservative therapy for acute meniscal injury, but have no value in this case.

(Choice 4) Active exercise can be employed as part of a rehabilitation program.

The correct answer is 5.

The combination of cough, hemoptysis, wheezing, and smoking history suggests the diagnosis of lung cancer. Of the two lung cancers listed, squamous cell carcinoma is the one that may produce parathyroid hormone (PTH) related peptide protein. PTH receptor leads to hypercalcemia. Small-cell carcinomas commonly produce antidiuretic hormone or adrenocorticotropin hormone. In a patient with Goodpasture, hemoptysis may present before hematuria, but because of the other symptoms, squamous cell carcinoma is the better choice. Renal cell carcinoma, not renal adenoma, may produce ectopic PTH related protein, and smokers do have an increased risk, but these patients present with hematuria, a palpable mass, flank pain, and a fever. The lack of an immunoglobulin G or A spike on serum protein electrophoresis should rule out multiple myeloma.

The correct answer is 3.

Epidural hematoma results from hemorrhage into the potential space between the dura and the skull. The hemorrhage most likely results from rupture to a meningeal artery, which travels within this plane; the middle meningeal artery, which branches off the maxillary artery in the temporal area, is most common. Normally, the patient experiences a lucid interval, defined as an asymptomatic period of a few hours after the trauma. A Berry aneurysm results from a defect in the media of arteries and is usually located at bifurcation sites. Berry aneurysms are most commonly found in the circle of Willis. The source of bleeding due to subdural hematoma is from bridging veins; these often occur in older adults as a result of minor trauma, and symptoms usually occur slowly days to weeks. Bacterial meningitis diagnosis is confirmed with lumbar puncture and demonstrates increased neutrophils/ protein and decreased glucose in the cerebrospinal fluid.

The correct answer is 3.

This patient has suffered blunt trauma and is now in shock as evidenced by his physical examination. Shock can be broadly defined as any state that causes perfusion inadequate to

meet the oxygen and nutrient demands of the tissues. In trauma or postsurgical patients, shock is presumed secondary to hemorrhage until proven otherwise. This patient has physical examination findings consistent with shock including hypotension, mental status change, and cool extremities. His trauma history, flat neck veins and sinus tachycardia implicate hypovolemia/ hemorrhage as the cause. The following table highlights the changes expected in progressively more severe classes of hemorrhagic shock.

(Choice 1) Cardiogenic shock occurs when the cardiac output is unable to meet the tissue’s oxygen demands. Decreased cardiac output would cause elevated venous filling pressures and jugular venous distention.

(Choice 2) Restricted ventricular filling, for example due to traumatic cardiac tamponade, could cause cardiogenic shock in a trauma. Elevated venous filling pressures and jugular venous distention would be expected.

(Choice 4) Blunt trauma with pulmonary injury can produce communications between the airways and blood vessels resulting air emboli, especially if positive pressure mechanical ventilation is superimposed. Patients with air embolism typically experience focal neurologic defects, hemoptysis and circulatory arrest.

(Choice 5) Loss of vascular tone occurs in septic shock and neurogenic shock. These forms of shock would be less likely to cause flattened neck veins and cool extremities and should respond positively to a 2 liter IV fluid bolus.

The correct answer is 2.

A solitary pulmonary nodule (SPN) is defined as a discrete lesion less than 3 cm in diameter incidentally discovered on chest x-ray. By definition, such nodules are surrounded completely by lung parenchyma and do not contact the pleura, hilum or mediastinum. Additionally there must not be any associated pleural effusion, adenopathy or atelectasis. The main goal of following SPNs is early detection of malignancies. Demographic data help to determine the patient’s risk; specifically, risk increases with age and smoking history. Radiographic studies

are the best tools for monitoring SPNs. In considering the likelihood of malignancy, radiologists consider the lesion doubling time. Lesions that enlarge very slowly (take longer than 1 .5 years to double) are typically benign, and those that double very rapidly (less than 30 days) are frequently infectious. The best radiographic test for making a determination of malignancy is high-resolution CT scanning. Factors seen on CT scanning that are associated with malignancy include increasing size, irregular or spiculated margins, stippled or irregular calcifications, and cavitation with thickened walls.

(Choice 1) Pulmonary function testing will not give any additional information regarding the biologic behavior of the mass in question. PFTs are often obtained as part of the routine follow-up of CO PD patients, or in lung cancer patients being evaluated for surgical fitness. (Choice 3) If the patient’s history and lesion’s radiographic appearance leave the question of possible malignancy in doubt, biopsy and culture may be useful. Biopsy may be obtained percutaneously or by video assisted thoracoscopic surgery (VATS).

(Choice 4) Bronchoscopy can be used to biopsy accessible lesions as well, but in general percutaneous biopsies and VATS carry a superior diagnostic yield.

(Choice 5) Chest x-ray monitoring at 3 months, 6 months, and then annually for 2 years is recommended for patients with incidentally discovered SPNs considered at very low risk for malignancy based on demographic and radiographic data.

The correct answer is 3.

The patient has a papillary adenocarcinoma of the thyroid that has metastasized to the cervical lymph nodes. These are the most common thyroid cancers and are usually found in women between 20 and 60 years of age. They are papillary tumors that are often mixed with follicles. Psammoma bodies (blue-staining calcium concretions) are an excellent marker for the cancer. Most patients initially present with palpable lymphadenopathy in the neck, which represents nodal metastasis via permeation of the lymphatics. They can produce a miliary pattern of metastasis to lung resembling miliary tuberculosis.

(Choice 1) Carcinomas of the larynx may involve the vocal cord; approximately 70% of these are found in the glottic area, 20% are found in the supraglottic region, and the remaining 10% are located in the subglottic or hypopharynx regions. Laryngeal carcinomas are usually squamous-celled. Those involving the glottic fold (i.e., true vocal cords) usually arise in the anterior half of one of the true vocal cords. They are usually papillary and rarely ulcerative. Due to the paucity of lymphatics in this area, the tumor tends to be locally malignant for a long time, and hence has a relatively good outcome. Often it is symptom free until the fifth or sixth decade of life; although cigarette smoking is a definite contributory factor, the greatest risk factor is consumption of alcohol. The most frequent and initial symptom is a change in voice a huskiness that becomes progressive. Thereafter, the patient can barely whisper, until finally, aphonia develops as the vocal cord becomes fixed. Although supraglottic tumors (which involve the false cords, laryngeal ventricles, or the base of the epiglottis) metastasize early to the cervical lymph nodes, those that involve the glottis remain localized for a long time. Subglottic carcinomas occur beneath the vocal folds, and the patient presents with difficulty in breathing. Metastasis occurs to the paratracheal and lower deep cervical nodes, and even the thyroid gland. Laryngeal carcinoma located in the hypopharynx is associated with dysphagia and pain on swallowing.

(Choice 2) The most common malignant parotid gland tumor is mucoepidermoid carcinoma. (Choice 4) The most common primary lung cancer is an adenocarcinoma with the formation of glandular structures.

(Choice 5) The most common breast cancer is an infiltrating ductal carcinoma. Papillary cancers are very uncommon.

The correct answer is 5.

At one time, all full thickness burns were allowed to heal by granulation over a period of 2 or 3 weeks, before skin grafting was done. The area was kept free of bacteria by the use of topical agents, such as the ones listed in the alternate answers. The process was expensive, painful, time-consuming, and prone to complications. The current preference is to do immediate excision and grafting of burned areas that appear to be full thickness, if they are not very extensive. This one is a perfect example.

(Choice 1) If the extent of the burn precludes early excision and grafting, mafenide acetate is used in areas where deep penetration is needed. Otherwise it is not a first choice because it hurts and can produce acidosis.

(Choice 2) Silver sulfadiazine is the “workhorse” of burn wound antibacterial therapy, but as pointed out, it would be a perfect choice only if we had to go the slow route of preparing the area for delayed skin grafts.

(Choice 3) Triple antibiotic ointment is preferred for burns around the eyes, as the other two topical agents are very irritating.

(Choice 4) Debridement is often indicated in the long-term preparation of an area to be grafted, but wet-to-dry dressings would be less effective than antibacterial agents. In any event, we want immediate excision and grafting for this patient.

The correct answer is 4.

The above upright radiograph shows free air under the diaphragm, a sign of perforation of an abdominal viscus. His presentation complaining of “sudden” onset abdominal pain also indicated perforation. The patient’s history of chronic epigastric pain is most likely due to

peptic ulcer disease, and given this, the diagnosis of perforated peptic ulcer is most likely. The patient’s diffuse abdominal pain is the result of a chemical peritonitis due to the release of gastric secretions into the peritoneum.

(Choices 1 & 6) Cholecystitis and biliary colic would not cause free air under the diaphragm though emphysematous cholecystitis may be associated with pneumobilia. Cholecystitis is associated with a positive Murphy’s sign, but this physical exam maneuver is not specific. Additionally, the presence of gallstones on ultrasound does not necessarily indicate cholecystitis or choledocholithiasis, as asymptomatic gallstones are very common. (Choices 2 & 3) Pancreatitis would not cause free air under the diaphragm. Additionally, pancreatitis is classically associated with dull, “boring” epigastric pain that radiates to the midback.

(Choice 5) Any perforated viscus can give free air. Diverticulitis usually starts with left lower quadrant pain and usually does not have the dramatic presentation with sudden abdominal pain.

The correct answer is 1.

Pneumonectomy is the preferred treatment for centrally located non-small cell cancers of the lung. The patient’s pulmonary function studies (prompted by the suggestion of chronic obstructive pulmonary disease) show that he can tolerate the removal of one third of his current lung capacity, as it would leave him with more than 800 mL forced expiratory volume

at 1 second (FEV1 ). However, there is no point in undertaking surgical therapy unless cure is possible, which would not be the case if he has liver metastasis, metastasis on the other lung, or involved mediastinal nodes at or above the carina. CT scan is the first step to answer those questions, before the pneumonectomy is considered.

(Choice 2) Radiation and chemotherapy would have been the chosen palliative therapy if metastatic spread had contraindicated surgery. It would also have been the correct answer if the tumor had been small cell, rather than squamous cell, carcinoma.

(Choice 3) The supraclavicular nodes can be involved in lung cancer, but they are not the first level. Thus, a negative biopsy would not have given the green light for surgery. If a CT scan does not give a satisfactory answer as to the status of mediastinal nodes, a cervical mediastinal exploration would be the procedure of choice to sample carinal nodes.

(Choice 4) Lobectomy is not suitable for central lesions, but it might have been the operation of choice for a peripheral tumor.

(Choice 5) Pneumonectomy is indeed our goal, but one would not do it without first making sure that extensive metastases are not present.

The correct answer is 4.

A penetrating wound to the chest will produce either a pneumothorax, a hemothorax, or both. The absence of breath sounds confirms that one of those has occurred, and the

hyperresonance to percussion indicates that air is present. The patient’s good vital signs indicate that there is time to do the proper diagnostic study (chest x-ray). The appropriate treatment for a pneumothorax is placement of a chest tube.

(Choice 1) would have been appropriate if the findings had suggested hemothorax (as evidenced by dullness to percussion), and he had been bleeding (as evidenced by low blood pressure and a fast pulse).

(Choice 2) A patient who is fully awake and alert, and who is speaking in a normal tone of voice, has an airway and can maintain it.

(Choice 3) Immediate insertion of a needle into the right pleural space would be appropriate management for a tension pneumothorax. If the patient had a tension pneumothorax, he would have been in shock and severe respiratory distress, and the mediastinum would have been shifted (evidenced by tracheal deviation).

(Choice 5) would be appropriate management for pericardial tamponade, which is not present in this patient. If the patient had developed tamponade, he would have been in shock, with a high central venous pressure (or distended veins).

The correct answer is 2.

A pelvic ultrasound is a safe, accurate, and useful technique in pregnant patients suspected of having an ectopic pregnancy. This procedure can identify an intrauterine pregnancy with considerable accuracy, effectively ruling out ectopic pregnancy. It should be the first imaging study performed.

(Choice 1) Although a CT scan may ultimately be needed, it is not the test of choice in a female with an early pregnancy because of the risks associated with radiation exposure. (Choice 3) An abdominal series is a nonspecific test that would not be helpful in ruling out an ectopic pregnancy and would expose an early pregnancy to unnecessary radiation.

(Choice 4) Culdocentesis is a diagnostic procedure that was more commonly used prior to the advent of ultrasonography. It entails placing an 18-gauge needle in the cul-de-sac of Douglas and aspirating the contents. A negative culdocentesis cannot definitively confirm or rule out an ectopic pregnancy.

(Choice 5) A diagnostic laparoscopy is a reasonable option, but only in cases in which other noninvasive modalities are unable to confirm a diagnosis.

The correct answer is 3.

All patients suffering traumatic amputations should be treated as candidates for reimplantation while in the field. As such, their amputated limb or digit should be wrapped in

sterile gauze, moistened with sterile saline and placed in a plastic bag. The bag should be then placed on ice and transported with the patient to the nearest emergency department. The amputated part should not be allowed to freeze. Packaging of the amputated part in this manner prolongs the viability of the part for up to 24 hours. Younger patients suffering sharp amputations with no crush injury or avulsion are the best candidates for amputation reimplantation.

(Choice 1) The amputated part should not be immersed in water as this may make digital vessel repair more difficult.

(Choices 2 & 4) The amputated part should not be placed in antiseptic solution or alcohol as chemical injury may occur. The patient will be appropriately treated with antibiotics and the amputated part irrigated and cleansed before reimplantation is attempted.

(Choice 5) The amputated part should not be placed directly on ice because this could result in frostbite injury to the amputated tissue and loss of viability.

The correct answer is 4.

Neurologic deficit is not uncommon after humeral shaft fractures. Radial nerve injuries are most common. Most of them resolve spontaneously after a few months. Compression of the brachial artery could cause pulse asymmetry, not necessarily indicating serious vascular injury. An attempt to align the humerus should be made first. If successful it takes 30sec and will, to some extent, restore the normal anatomy of the limb. It would decrease the patient’s pain and discomfort. Then, the pulses must be checked again. Failure to perform the alignment easily indicates that muscles, nerves, or vessels are entrapped in the fracture site. In such a case, operation is required.

(Choices 1,2,3 & 5) are correct, but choice 4 should be attempted first.

The correct answer is 2.

The central cord syndrome classically occurs with hyperextension injuries in elderly patients with degenerative changes in the cervical spine. Such a traumatic injury causes selective damage to the central portion of the anterior spinal cord, specifically the central portions of the corticospinal tracts and the decussating fibers of the lateral spinothalamic tract. Central cord syndrome is characterized by weakness that is more pronounced in the upper extremities than in the lower extremities. This unique motor deficit occurs because the motor fibers serving the arms are nearer to the central part of the corticospinal tract. Rarely, a patient may also have a selective loss of pain and temperature sensation in the arms due to damage to the spinothalamic tract.

(Choice 1) Brown-Sequard syndrome (hemisection of the cord) is classically associated with ipsilateral loss of vibration and proprioceptive sensation as well as ipsilateral spastic paresis.

(Choice 3) Cerebral contusion usually causes an altered level of consciousness (due to edema) with the risk of seizure; focal neurologic signs may be present.

(Choice 4) Posterior cord syndrome is associated with bilateral loss of vibratory and proprioceptive sensation.

(Choice 5) The anterior cord syndrome should be suspected when there is bilateral spastic motor paresis distal to the lesion. It usually occurs secondary to occlusion of the vertebral artery.

The correct answer is 2.

The patient described is most likely suffering a tibial stress fracture. The tibia is the most common bone in the body to be affected by stress fractures, and the patients affected by this condition are most commonly competitive athletes. A stress fracture can occur even in conditioned athletes after only four to six weeks of intense training. Patients who participate in running sports classically obtain stress fractures in the distal third of the tibia on the posteromedial border while patients involved in jumping sports, such as dancing, classically obtain stress fractures in the middle third of the tibia on the anterior side of the bone. Patients

typically complain of pain with activity that improves with rest. If activity is continued, the pain may persist during rest. Point tenderness to palpation over the fracture is present on exam. X-rays are usually normal, but they may reveal periosteal reaction in the site of the fracture. The injury is best defined radiographically using CT or bone scan.

(Choice 1) Ligamentous tear is unlikely in the midpoint of the leg as there are no ligaments in this location other than the interosseus membrane.

(Choice 3) Bone infection is unlikely in this patient because the ESR is not elevated.

(Choice 4) Nerve entrapment typically presents with radiating pain and is not typically reproducible with palpation. This patient has localized pain and point tenderness.

(Choice 5) Bone neoplasms typically present with pain and tenderness and may be complicated by pathologic fractures. Metastases to bone are more common than primary bone tumors and these typically affect the axial skeleton or proximal humerus and femur. Usually radiographic evidence of bone destruction or tumor is evident on x-ray in these cases.

The correct answer is 2.

Acute carbon monoxide poisoning should be considered in all patients who are exposed to smoke, especially in a closed space. Carbon monoxide has over 200 times higher affinity for hemoglobin than does oxygen, and it impairs the delivery of oxygen to tissue by shifting the hemoglobin-oxygen dissociation curve to the left. Carbon monoxide toxicity affects the

organs with the highest demand for oxygen first, namely the brain and heart. This explains the early manifestations of carbon monoxide poisoning, which include confusion, agitation and somnolence. Chest pain or arrhythmias resulting from cardiac hypoxia may also occur. The treatment of carbon monoxide poisoning is administration of 100% oxygen via nonrebreather facemask and regular monitoring for at least four hours. 100% oxygen can decrease the half-life of carbon monoxide from three to four hours on room air to approximately one hour. Hyperbaric oxygen can be used in severe cases not responsive to facemask-administered oxygen.

(Choice 1) Endotracheal intubation is not required for administration of 100% oxygen. This patient is breathing spontaneously and is conscious, so intubation is not required.

(Choices 3 & 4) A bolus of 50% dextrose and intravenous thiamine is indicated in any unconscious patient as an emergency measure to assess for hypoglycemia. This patient is not unconscious and the etiology of her acute confusion is evident.

(Choice 5) Intravenous morphine in emergency setting is indicated as one component of the treatment for acute pulmonary edema. In this patient, morphine would be counterproductive because it would suppress her respiratory drive.

37. Question

The correct answer is 3.

The patient described is suffering from a flail chest. Clues that support this diagnosis include the x-ray findings (i.e., multiple rib fractures and opacification of the left lung, which is likely the result of a pulmonary contusion), coupled with the patient’s presentation (i.e., severe tachypnea and respiratory distress following major thoracic trauma). Classically, flail chest occurs following fractures of numerous contiguous ribs in two or more locations. Due to severe pain, patients with flail chest take shallow breaths and compensate for the resulting hypoxemia with hyperventilation. Trauma severe enough to cause flail chest also typically causes a significant pulmonary contusion, which is regarded as the primary reason for respiratory distress in patients with such an injury. On examination, the isolated thoracic wall segment may exhibit paradoxical inward motion on inspiration, and outward movement on expiration. Intubation with mechanical positive pressure ventilation is required in many patients with this injury, but pain control and supplemental oxygen are the most important early steps in management.

(Choice 1) A massive hemothorax, defined as a hemorrhage of at least 1500 cc of blood into a hemithorax, would cause hypotension, tachycardia and respiratory distress. X-ray typically shows an aerated lung surrounded by fluid.

(Choice 2) A large traumatic rupture of the diaphragm would be required to cause the degree of respiratory distress seen in this patient. On x-ray, this would show an abnormality of the diaphragmatic shadow and herniation of abdominal contents into the left pleural space. Additionally, the tip of the nasogastric tube is typically seen in the left hemithorax in diaphragmatic ruptures.

(Choice 4) Tension pneumothorax can cause respiratory distress, hypotension and tachycardia; however, the typical x-ray findings are tracheal and mediastinal displacement to the contralateral side, and excessive radiolucency of the affected side.

(Choice 5) Lobar atelectasis or complete collapse of an entire lung could compromise respiratory gas exchange; however, this patient’s chest x-ray shows lung markings at much of the periphery of each thoracic cage, thus indicating that ventilation is occurring in all areas of both lungs.

The correct answer is 3.

This patient’s history of motor vehicle accident, ecchymosis over the abdominal wall in distribution of the seat belt and decreased bowel sounds is suspicious for blunt abdominal trauma. Furthermore, collapsed neck veins and hypotension indicate hemodynamic instability. In a hemodynamically unstable victim of blunt abdominal trauma, administration of intravenous fluids, followed by FAST (Focused Assessment with Sonography for Trauma), is the appropriate course of action. Ultrasound images, however, tend to be of low quality in patients with obesity. For any case in which ultrasound images are not definitive, diagnostic peritoneal lavage should be performed. In diagnostic peritoneal lavage, a catheter is inserted via an abdominal incision and fluid is aspirated for signs of bleeding. If either ultrasound or peritoneal lavage demonstrates hemoperitoneum, the patient should then undergo laparotomy and surgical repair.

(Choice 1) ACT scan of the abdomen is the appropriate assessment for hemodynamically stable victims of blunt abdominal trauma. In this patient with hemodynamic instability, a CT scan would not be appropriate.

(Choice 2) Plain x-ray films of the abdomen are of limited utility in assessment of blunt abdominal trauma and have low sensitivity for identifying sources of bleeding.

(Choice 4) If peritoneal lavage in this patient were to demonstrate hemoperitoneum, the patient would then undergo laparotomy. Physicians may skip straight to laparotomy in patients who cannot be stabilized or have clear evidence of pneumoperitoneum or diaphragmatic rupture.

(Choice 5) A chest x-ray is very useful for identifying free air in the abdomen. It would also help in identifying thoracic injury in the patient. However, it is not sensitive for detecting hemoperitoneum.

The correct answer is 4.

Duodenal injury may occur during blunt trauma when the duodenum is compressed between the spine and an external solid structure like a steering wheel or seat belt during high-speed decelerating trauma. The second part of the duodenum, being retroperitoneal and therefore the least mobile is the most commonly injured part of the duodenum in blunt abdominal trauma. Isolated duodenal injuries can be easily missed because the symptoms are subtle. Patients may complain of epigastric pain, nausea and vomiting. Peritoneal signs are usually not present because the rupture is contained within the retroperitoneum. Retroperitoneal air on abdominal x-ray is very suggestive. CT scan of the abdomen with oral contrast confirms the diagnosis of duodenal injury and will also disclose the presence of a concomitant duodenal hematoma.

(Choices 1 & 5) Noncontrast CT of the abdomen and ultrasound are not sensitive for duodenal injuries. An ultrasound, however, is very useful in determining injury to many other abdominal viscera and is routinely employed in the focused assessment with sonography for trauma (FAST) exam, which aids surgeons in determining if a patient requires an emergent exploratory laparotomy.

(Choice 2) DPL is not sensitive for duodenal injuries because the second part of the duodenum, the most commonly injured portion of the duodenum, is retroperitoneal. DPL has largely been replaced by the FAST exam in the assessment of abdominal trauma.

The correct answer is 4.

The mechanism of injury and symptomatology are consistent with fracture of the scaphoid bone. The most important due to diagnosis is the presence of pain on pressure in the “anatomic snuffbox.” Plain x-ray films in the first 24-48 hours usually fail to reveal evidence of fractures, and the patient may be mistakenly diagnosed as having a sprain. In the presence of the characteristic history and findings on physical examination, appropriate treatment for presumptive scaphoid fracture should be instituted, until proven otherwise.

(Choice 1) may be performed to confirm the presence of scaphoid fracture. It is more sensitive than plain x-rays, but it frequently gives false negative results in the first 48 hours following trauma.

(Choice 2) MRI examination of the wrist, as well as CT scans, can be performed if there is a need for prompt confirmation of the clinical suspicion of scaphoid fractures. However, these radiologic investigations are not cost-effective.

(Choice 3) Treatment for wrist sprain is the most common mistake when dealing with scaphoid fractures, especially because plain x-ray films are often negative in the first day or two after the fracture occurs. Missed scaphoid fracture is among the top 10 reasons formal practice suits.

The correct answer is 5.

The presentation of this patient is classic for rupture of the duodenum. Patients have vague symptoms because the duodenum is retroperitoneal. If left untreated, mortality is almost 1 00%. The best way to diagnose it is to maintain a high index of suspicion and conduct repeated physical examinations. Serum amylase is often elevated but is not diagnostic. X-ray films of the abdomen reveal retroperitoneal air, which is the sine qua non of duodenal rupture. Duodenal rupture in children could also result from the use of the lap belt without shoulder support in motor vehicles. This results from acute hyperflexion of the thoracolumbar spine, which crushes the duodenum. Drivers of motor vehicles can also sustain duodenal rupture as a result of compression against the steering wheel. This possibility is greatly reduced by an air bag.

(Choices 1 & 2) This patient does not have a ruptured spleen or a ruptured liver, because his vital signs are stable. Moreover, neither condition is associated with midabdominal pain. Rather, pain is in the left or right upper quadrant, respectively, and there may be associated fractures of the lower ribs. A diagnostic peritoneal lavage is positive for hemorrhage, and a computed tomography (CT) scan confirms the diagnosis.

(Choice 3) usually follows blunt trauma. Although this diagnosis is a possibility, the duodenum more usually ruptures in injuries like the one described in the scenario. Pancreatic rupture is associated with hypovolemic shock due to tear of the gastroduodenal artery. The common bile duct may be avulsed as well. Serum amylase is raised, but this alone does not confirm the diagnosis. However, a persistently elevated serum amylase suggests this possibility. The diagnosis is best established by maintaining a high index of suspicion. A CT scan confirms the diagnosis.

(Choice 4) is a benign condition. The pain is confined to the region of injury and is not vaguely defined. Pain increases with contraction of the abdominal muscles. A localized mass may be present. The diagnosis is clinical, and treatment is supportive.

The correct answer is 1.

The clinical scenario described is suggestive of early dumping syndrome, a common postgastrectomy complication. Up to 50% of patients with partial gastrectomy may experience this syndrome. The rate is lower for patients who underwent more conservative gastric surgery (e.g., proximal vagotomy). The pathophysiology of this condition involves rapid emptying of hypertonic gastric content into the duodenum and small intestine. This process leads to the fluid shift from intravascular space to the small intestine, release of intestinal vasoactive polypeptides, and stimulation of autonomic reflexes.

(Choice 3) The diagnosis is made clinically, but provocative tests and contrast x-ray studies to demonstrate rapid gastric emptying are occasionally used.

(Choices 2,4 & 5) Endoscopy does not help to confirm the diagnosis. Dietary changes, including small and frequent meals and avoidance of simple carbohydrates, are tried first, and these are usually effective in the majority of patients. Besides that, the symptoms usually diminish over time. In resistant cases, octreotide, a somatostatin analog or reconstructive surgery should be tried.

The correct answer is 3.

All patients with traumatic wounds should be assessed for the need for tetanus immunoglobulin (TIG), which provides passive, temporary and immediate immunity, or tetanus toxoid (TT), which provides active, prolonged but delayed immunity. The current recommendations are as follows:

All other wounds include those at high risk of allowing growth of the vegetative C. tetani organism. Those include wounds that provide an anaerobic environment for growth including puncture wounds, projectile wounds, wounds containing foreign bodies, sites of active infection by other organisms or wounds containing necrotic tissue. The patient described in the vignette should be treated with tetanus toxoid as she has suffered a severe wound at risk of harboring C. tetani, and it has been greater than five years since her last booster vaccination.

(Choice 1) The protection given by tetanus toxoid vaccination wanes with time and administration of an “early” booster is required after a severe injury even in vaccinated individuals.

(Choices 2 & 4) Tetanus immunoglobulin is not required in this individual as she has already had a complete initial series of three tetanus vaccinations.

(Choice 5) After the onset of symptoms, therapy is aimed at eliminating the production of tetanospasmin (antibiotics such as metronidazole or penicillin), removing any unbound tetanospasmin (TIG), pharmacologic control of muscle spasms and airway protection I respiratory support.

The correct answer is 4.

This patient has a prolapsed intervertebral disk involving the L4-5 level. A herniated disk at this level will typically compress the fifth lumbar nerve root. The distribution of sensory deficit in such cases would be along the medial side of the leg and in the web space between the first and second toes. Since the fifth lumbar nerve root is required for effective dorsiflexion of the foot, weak dorsiflexion is to be expected, and is indeed noted on the vignette. These patients have difficulty standing on their heels. The initial management is conservative, bed rest; nonsteroidal analgesics, muscle relaxants, and physiotherapy usually fracture of the temporal bone. It may also occur in patients on anticoagulants or who have bleeding diathesis, but these patients usually have suprachoroid hemorrhage.

(Choice 1) is incorrect; epidural hematoma is an acute event. This can result from trauma or in patients who have been on anticoagulants or have bleeding diathesis. The patients usually have sudden localized pain, which could result in cord compression. A computed tomographic (CT) scan will reveal the hemorrhage. Treatment is surgical decompression. (Choice 2) is incorrect; a spinal cord astrocytoma is intradural and intramedullary in location. It usually affects people between the ages of 25 and 40. This is a slow-growing tumor that is associated with a long history of slowly progressive backache. The pain is usually localized, and in some cases may be radicular, namely spreading down along the path of a sensory nerve root. The tumor arises from the gray or white matter of the spinal cord. Pain is followed by motor weakness of the lower extremities, and sensory symptoms are usually the last to occur. Treatment is surgical resection.

(Choice 3) is incorrect; an epidural abscess is an acute event and is rare. The patient would have severe localized pain, and tenderness would be noted over the vertebral spine where the abscess is located. In addition, fever may be present. Radiculopathy is unusual. Treatment is surgical.

(Choice 5) is incorrect; an L5-S1 prolapsed intervertebral disk compresses the SI nerve root. Such patients have pain along the lateral side of the leg and hypesthesia over this region and along the little toe. They also have difficulty with plantar flexion and standing on their toes. The ankle jerk is depressed or absent, as the SI nerve root innervates it. The initial management is the same as that for a prolapsed L4-5 intervertebral disk.

The correct answer is 5.

An arteriogram is important to define the anatomy and demonstrate the location of vessel occlusion. The superficial femoral artery is the most common site of occlusion, as shown in the angiogram in image above (note the arrow). The cause of a sudden occlusion should be determined. The most common source involves the heart; atrial fibrillation is seen in approximately 85% of all such cases. Other sources include aneurysms and atheromatous plaques proximal to the site of occlusion.

(Choice 1) Deep vein thromboses are caused by venous stasis, not seen by angiography. (Choice 2) Although an abdominal aortic aneurysm can be the source of an embolism to the lower extremities, it is less likely than the most common cause, which is from the heart. (Choice 3) Blue toe syndrome occurs when atheromatous plaques are showered from the artery into the periphery. It is usually seen after cardiac catheterization.

(Choice 4) A fat embolism can be seen in cases of long bone fractures. It usually occurs in the pulmonary vasculature.

The correct answer is 1.

This patient is presenting with acute cholecystitis and should be observed prior to undergoing elective cholecystectomy during the same hospitalization. Acute cholecystitis refers to inflammation and distention of the gallbladder, typically due to obstruction of the cystic duct by a gallstone. It presents with acute right upper quadrant pain and tenderness, plus fever and leukocytosis. Physical exam may reveal a positive Murphy’s sign. The gallbladder is palpable in 1 / 3 of cases. Patients with sickle cell anemia are at increased risk of developing gallstones because their ongoing hemolysis increases bilirubin concentrations and drives bilirubin stone formation. Ideally, acute cholecystitis is managed conservatively, with observation followed by elective cholecystectomy during the same hospital admission. Symptoms often subside within a few days with volume resuscitation, antibiotics, and pain medications. However, early cholecystectomy (performed within a few days of presentation)

reduces disease duration, hospitalization length, and cholecystitis-associated mortality. This woman has had ongoing biliary colic, is at high risk for disease recurrence, and does not have any contraindications to surgery. Thus, she should receive supportive care initially and then cholecystectomy within a few days.

(Choice 2) ERCP uses a fiberoptic camera to visualize the biliary and pancreatic ducts for diagnostic and therapeutic purposes. It would be reasonable to perform ERCP if the patient had choledocholithiasis or a gallstone in the common biliary duct (CBD) causing CBD dilatation. In such cases, sphincterotomy can help facilitate passage of stones.

(Choice 3) Emergent cholecystectomy is required for patients with biliary gangrene or perforation.

(Choice 4) The HIDAscan is a nuclear medicine study used to diagnose gallbladder obstruction. With this technique, a nuclear tracer is injected into the blood and collects in the gallbladder. If the tracer is not expelled from the gallbladder, an obstruction is diagnosed. For the patient above, the diagnosis of cholecystitis is not in doubt, so a FIIDAscan is not necessary.

(Choice 5) Percutaneous transhepatic gallbladder drainage is a technique used to decompress the gallbladder in patients who are unstable or have a contraindication to surgery. This patient is stable and should undergo elective cholecystectomy.

The correct answer is 4.

This patient experienced a severe deceleration injury. He is hypotensive, tachycardic, and minimally responsive. He is in hemorrhagic shock. The chest x-ray reveals a widening mediastinum, suggesting a rupture of the thoracic aorta, which is a common catastrophic injury in deceleration accidents. This patient is in grave danger. After confirmation of the diagnosis by spiral CT scan, the treatment is immediate surgical repair of the injury with fluid and blood resuscitation.

(Choice 1) is common in blunt-force injuries in which the steering wheel has crushed the chest. Arrhythmias, bundle branch block, or ECG abnormalities mimicking infection may occur. Pericardial effusion or rupture may develop.

(Choice 2) is associated with hypotension and tachycardia. However, pulsus paradoxus (systolic blood pressure drops > 10 mm Hg on respiration) and distant heart sounds might be discovered on physical examination, and his central venous pressure would be high. Chest x-ray films would show an enlarged cardiac silhouette. The ECG would exhibit low limb-lead voltage and variable QRS amplitude (electrical alternans). However, pericardiocentesis is both the diagnostic and therapeutic procedure of choice.

(Choice 3) is diagnosed when a part of the chest wall bound by fractured ribs moves paradoxically during respiration. Ventilation is hampered.

(Choice 5) occurs when air can enter but not leave the pleural space. The mediastinum appears to be shifted to the contralateral side on chest x-ray films. A region without peripheral lung markings outlined by a sharp pleural margin is characteristic. Breath sounds are depressed or absent on the affected side.

The correct answer is 5.

Most head injuries are mild and will not progress to more serious clinical scenarios. Patients who have suffered head injuries may be classified into low-risk and moderate-risk and high- risk groups. Patients with low-risk head trauma will frequently be asymptomatic or may experience mild headaches or dizziness. Such patients have a GCS of 14 or 15 and have not lost consciousness. Such patients may be discharged with no further imaging or studies if a reliable individual can monitor them for 24 hours following the injury. Patients with moderate- risk head injuries may have any of the following characteristics: evidence of skull fractures, loss of consciousness, emesis, severe headache, amnesia or seizure. These patients should have a CT scan. If the CT scan is normal, such patients may be discharged with printed instructions (list of symptoms) that require immediate return to hospital. Patients with severe head injuries typically display altered or lost consciousness and focal neurologic signs. Such patients may have gross evidence of a depressed skull fracture or penetrating injury to the head. This group of patients requires emergent imaging and assessment for intervention as well as admission to the hospital regardless of findings.

(Choice 1) CT scans are superior to skull radiographs for assessing head injury as a CT scan can detect skull fracture as well as hemorrhage, hematoma and displacement of the midline structures in the head.

(Choices 3 & 4) Admission is not required for patients with mild to moderate head injuries with normal head CT scans. Admission is indicated in patients with moderate injury and positive findings on imaging or in patients with any severe head injury.

The correct answer is 4.

To perform hemodialysis, it is necessary to surgically form an arteriovenous (AV) fistula. This is accomplished by creating an opening in which the artery is sewn onto a vein; this is usually is done in an arm. In hemodialysis, blood is withdrawn from an artery and returned via a vein. However, veins are typically too small to accommodate the amount of fluid returned and therefore must be enlarged. In an AV fistula, the arterial blood pressure eventually enlarges the vein, thus permitting insertion of a large needle or cannula. Nonsurgical AV fistulas also do occur. These may be congenital or acquired, caused by trauma or by erosion of an arterial aneurism into an adjacent vein. Congenital AV fistulas are uncommon but acquired AV fistulas can be caused by any injury that damages an artery and a vein that lie next to each other. Most often the injury is a piercing wound caused by a knife or a bullet. Symptoms of the fistula may show up immediately or after several hours. If the fistula is superficial, escaping blood often causes swelling. However, in a large, spontaneously acquired AV fistula, the flow of blood under pressure into the venous system stretches the veins and more blood flows through the venous system than through the arterial system. This causes the blood pressure to fall, making the heart pump more vigorously and potentially resulting in high output failure.

A renal biopsy (Choice 1) is performed by inserting a long needle into a kidney from the back, usually in a lightly sedated individual. Most commonly, three samples are obtained and evaluated for possible pathologies. Such biopsies are sometimes recommended to help evaluate hematuria, proteinuria, and/or elevated creatinine or blood urea nitrogen (BUN) levels.

(Choices 2 & 3) Insertion of a catheter, whether by making a small incision in the abdomen or by performing more invasive surgery, are operations used to perform peritoneal dialysis in which a hypertonic dialysis fluid is added into the patient’s peritoneal cavity via an implanted catheter. The hypertonicity of the dialysis solution draws low-molecular-weight molecules (e.g., water, salts, and waste products) from the blood system into the peritoneum, which soon becomes saturated; consequently, the old solution must be drained and replaced by fresh dialysis solution.

(Choice 5) is not likely to play a role in treatment of chronic renal failure, although it may play a role in treatment of postrenal acute kidney failure.

The correct answer is 2.

All the findings indicate obstructive jaundice (high alkaline phosphatase, dilated ducts), with gallstones as the source. The fact that no stone can be seen impacted within the common duct is meaningless, since only about 50% of those can be seen by sonogram (the air in the duodenal loop interferes with the study). Endoscopic retrograde cholangiopancreatography (ERCP) can outline the stone and even allow extraction, limiting subsequent surgery to cholecystectomy.

(Choice 1) Serology would have been a splendid idea if she had very high transaminases and minimal elevation of the alkaline phosphatase, and if the sonogram had shown normal size ducts.

(Choice 3) Ampullary cancer should be suspected in the patient with obstructive jaundice, along with anemia and occult blood in the stool; this is not the case here.

(Choice 4) Liver biopsy assumes that we expect intrinsic liver disease, which is not the case here.

(Choice 5) Neither should we suspect cancer of the pancreatic head when the gallbladder is contracted rather than dilated and all the signs point to stones as the problem. ERCP will also give us the diagnosis in the case of the rare patient with two diseases (stones plus an unrelated cancer).