1–A. This patient is experiencing a classic manifestation of refeeding syndrome. Refeeding syndrome is seen in severely malnourished patients when aggressive calorie support is initiated, particularly when a large percentage of those calories are provided as carbohydrates. The infusion of carbohydrates results in rapid and extensive peripheral uptake and utilization of glucose. The intracellular utilization of glucose requires the use of a significant amount of intracellular PO4-, therefore potentially resulting in severe hypophosphatemia. Characteristics include malaise, lethargy, perioral paresthesias, tremors, dysarthrias, coma, and even death. Treatment involves slowing administration of nutritional support and administration of PO4- salts. Thiamine would most likely be provided in the vitamin supplementation and would generally not be associated with such a temporal relationship to parenteral nutrition administration. Insulin may help to decrease overall serum glucose levels, however, it would not specifically address the most serious acute issue of severe hypophosphatemia. MgCl2 administration also does not address the primary issue of hypophosphatemia.
2–B. In an adult, satisfactory urine output is 0.5–1.0 mL/kg/hour, and in a patient with a large burn it needs to be measured continuously with a Foley catheter. An appropriate goal for adequate urine output in this patient is 40–80 mL/hr based on his weight of 80 kg. In a patient with severe burns a minimum of two large-bore intravenous (IV) lines are necessary. Burn patients are extremely hypermetabolic, and have numerous reasons to be tachycardic other than hypovolemia. Edema secondary to leaky vascular membranes is common in patients with severe burn injuries and is not a marker of overhydration.
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3–E. Ketamine is unique among anesthetic agents in that it provides anesthesia, analgesia, and possibly amnesia. It is also a potent bronchodilator and tends to maintain cardiac output and blood pressure. Unfortunately, emergence reactions are common. Midazolam, a benzodiazepine with reliable anxiolytic and amnestic properties, can greatly attenuate these reactions. Propofol, fentanyl, lidocaine, and etomidate are other anesthetic agents frequently used for cardioversions, however, these agents do not provide the effective amnestic effect provided by midazolam.
4–B. This patient most likely has appendicitis based on his age and presenting symptoms. The psoas sign is pain in the lower abdomen and psoas region that is elicited when the thigh is flexed against resistance. It suggests an intra-abdominal inflammatory process most frequently associated with appendicitis. Crepitus suggests a rapidly spreading gas forming infection and is a rare finding. Murphy's sign suggests acute cholecystitis, while flank and periumbilical ecchymosis suggest retroperitoneal hemorrhage, often caused by hemorrhagic pancreatitis.
5–B. This patient has developed necrotizing fasciitis of the perineal and scrotal region (Fournier's gangrene) probably originating from an intra-abdominal source (e.g., diverticulitis). Management requires early and aggressive surgical débridement of the affected region. Generally, given the differential blood supply between the scrotum and the testicles, as well as the thick dartos fascia surrounding the testicles, superficial infections of the scrotum extending from the perineum do not affect the testicles, thus orchiectomy is generally not necessary. In some circumstances, persistent infections in the perineal region require fecal diversion with a colostomy to avoid persistent fecal contamination and inhibition of healing. Although resection of the affected colon would be considered appropriate, a primary reanastomosis would not provide for fecal diversion. Sitz baths and antibiotics would be inadequate therapy without surgical débridement.
6–C. Although rare, one of the potentially serious complications associated with laparoscopic intraperitoneal hernia repair is the risk of iatrogenic bowel injury. It is unlikely that a strangulated hernia went undiagnosed prior to or during an elective inguinal hernia repair. It is also unlikely that the hernia would recur by postoperative day 1. In addition, wound infections and adhesion formation do not develop this quickly in the postoperative period and would not necessarily be associated with rebound and guarding.
7–C. Acute renal failure (ARF) is defined as an abrupt change in renal function such that plasma creatinine and urea levels are elevated. Oliguria (< 0.5 mL/kg urine output per hour) or anuria are usually present. Prerenal failure suggests inadequate blood flow to the kidney. Causes of intrinsic renal failure include acute tubular necrosis, nephrotoxicity secondary to drugs, hemoglobinuria, and myoglobinuria. Postrenal failure causes usually present with acute anuria caused by any obstruction to urinary flow from the collecting ducts to the urethra. The fractional excretion of sodium (FENa) and urine specific gravity can help to delineate prerenal causes from other causes of acute renal failure. Urinalysis including cytology may assist in identifying an intrinsic renal injury. Hemodialysis may be necessary as a bridge due to severe hyperkalemia, metabolic acidosis, uremic complications, and volume overload until renal function returns to normal. Most cases of acute renal failure in this setting will resolve.
8–E. A focal bile duct stenosis in the absence of a history of abdominal surgery is highly suggestive of a biliary neoplasm. Furthermore, this patient presented with a history of painless jaundice, which is also suggestive of malignancy. Primary sclerosing cholangitis may also present with a focal stenosis but usually at an earlier age and with a fluctuating clinical course. Cholangitis and Mirizzi's syndrome would be highly unlikely in a patient with a normal white count and no pain.
9–A. Corticosteroids decrease hypertrophic scarring by enhancing collagenase activity. This is related to an increase in collagen degradation within the hypertrophic scar. Injecting corticosteroids directly into a scar prevents acute inflammation in the healing wound. Injecting keloids and hypertrophic scars with corticosteroids has no effect on the number of fibroblasts present. Collagen turnover is not increased in treated scars. Pressure treatment is not necessary after corticosteroid injection. Corticosteroids do not affect intracellular collagen synthesis or extracellular collagen cross-linking. The cross-linking process contributes to the tensile strength in a healing wound. Increased collagen solubility is not caused specifically by cross-linking.
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10–C. Fever, chills, back pain, hemoglobinuria, and rapid deterioration of the cardiovascular and respiratory systems are classic signs of a severe immune reaction to transfused blood caused by ABO incompatibility, as seen in this patient. The cause of this reaction is preformed antibodies in the recipient's serum reacting to nonself antigens on the donor's red blood cells (RBCs) [i.e., patients with Type A blood have antibodies to Type B RBCs]. Bacterial contamination of donor blood is rare and generally would not present within the first few minutes of administration. Donor leukocytes can react with recipient cells, but this is not generally associated with a severe transfusion reaction. It may, however, cause fever and chills in a small number of patients. Volume overload secondary to too-rapid administration of blood can be associated with dyspnea and respiratory insufficiency, but is not associated with the other findings. Hypocalcemia rarely occurs, even with massive transfusions, and would not be associated with the findings in this patient.
11–A. Glucocorticoids are used in most multidrug immunosuppression protocols. In addition, they are commonly used as the first line therapy for rejection by administration of boluses over one to several days. If steroids fail, monoclonal or polyclonal antibodies are added to the regimen. Cyclosporine and azathioprine are essential in maintenance therapy but play no role in the treatment of acute rejection. Mycophenolate mofetil decreases the rate of rejection particularly for kidney transplants, but again plays little or no role in the treatment of acute rejection once it has developed. Cyclophosphamide is rarely used in transplant recipients either for maintenance or for treatment of rejection.
12–D. Although hemorrhage in such a patient could originate from many different sources, upper gastrointestinal bleeding is a frequent cause of hemorrhage in critically ill surgical patients generally resulting from acute stress gastritis. The patient's risk factors include hospitalization with a long stay in the intensive care unit and sepsis. Although airway management and volume resuscitation are initial management steps, early placement of a nasogastric tube may confirm that the bleeding is from an upper gastrointestinal source. In addition, checking the stools for blood (i.e., guaiac test) may also provide support for a gastrointestinal source of bleeding in patients with a falling hematocrit. In the absence of other signs of an intra-abdominal process (e.g., acute abdomen), emergent laparotomy or mesenteric angiography are not indicated at this point in the management of this patient.
13–E. Although conservative medical management of esophageal perforation is appropriate for a small, select group of patients, it is generally reserved for those who have no evidence of sepsis or communication of the rupture with the pleural or peritoneal cavities. In theory, these patients have already “defended themselves” against the rupture and should do well with conservative management with antibiotics and drainage. Boerhaave's syndrome ruptures tend to be the most morbid because of the high incidence of pleural or peritoneal contamination and delayed diagnosis. Survival in these patients is 75%–85% and those presenting earlier tend to fare better than those presenting after 72 hours. Patients who present less than 24 hours after the injury are generally candidates for reinforced primary closure of the perforation. Esophageal rupture secondary to Boerhaave's syndrome usually results in a tear on the left lateral wall, just above the diaphragm. Thus, a left pleural effusion is a common finding on chest radiograph.
14–C. Both the benzodiazepines and most barbiturates are excellent anti-epileptics. Propofol and etomidate also likely possess antiseizure properties but it is thought that etomidate in low doses may provoke seizures. Either midazolam or a low dose of thiopental would rapidly terminate this seizure caused by this unintentional intravascular injection of bupivacaine. Succinylcholine would mask the convulsions, and narcotics (such as fentanyl) also do not suppress seizures. Lidocaine is not as toxic as bupivacaine, but can cause seizures if too much is given intravenously.
15–B. Branched-chain amino acids are essential amino acids and include leucine, isoleucine, and valine. These amino acids are preferentially metabolized by the muscle and therefore in the setting of significant liver disease administering these substrates may decrease the overload of total protein and provide for mechanisms of more efficient glucose production. Administration of nutritional supplements with a high percentage of branched-chain amino acids versus other amino acids may decrease the degree of encephalopathy seen in patients with severe liver failure. These amino acids are not preferentially metabolized by the liver and do not act as hepatotoxins.
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16–E. Gallstone ileus is the obstruction of the small intestine (usually at the ileocecal valve) caused by a gallstone that has entered the duodenum through a fistula formed between an inflamed gallbladder and the duodenum. The usual signs of intestinal obstruction are found, plus air in the biliary tree. There is usually a history of attacks of cholecystitis or cholelithiasis. While air in the biliary tree may represent cholangitis, this finding in association with a small bowel obstruction (SBO) without other identifiable causes should raise suspicion for gallstone ileus. Superior mesenteric artery syndrome is a rare cause of duodenal obstruction caused by external compression of the third portion of the duodenum by the overlying vessel. It is characteristically seen in patients with rapid weight loss or those in SPICA casts. The obstruction is proximal and is not associated with distension of small bowel as described above. Right-sided colon cancer can mimic distal SBOs but is not associated with air in the biliary tree. Because the patient has not had prior abdominal surgery, adhesive obstructions would be improbable. Uncomplicated sigmoid diverticulitis is generally not associated with air in the biliary tree.
17–C. Even though less than 1% of all breast cancer occurs in men, it is most likely that this patient is suffering from breast cancer. There are approximately 900 new cases of male breast cancer per year and most cases present with an isolated mass or enlargement of a single breast. The mean age of presentation is 60–65 years with a prominent risk factor being a protracted hyperestrogenemic state. These tumors are ductal in origin, and 80% are estrogen receptor-positive. These tumors tend to become systemic early, with axially node metastasis, or involvement with the chest wall or skin. Therefore, they usually present at a late stage, and a lumpectomy and axillary node dissection is inadequate to remove the majority of the tumor burden. Treatment is a radical mastectomy after the diagnosis is confirmed with fine needle aspiration (FNA) or biopsy. Chemotherapy is needed for adjuvant therapy, but is inadequate single therapy.
18–B. The presence of free peritoneal air in the setting of acute diverticulitis is an indication for emergent laparotomy and resection of the affected colon with formation of an end colostomy and performance of a Hartmann's procedure (oversewing of the unaffected rectosigmoid distal to the resection site creating a pouch drained through the anus). Reanastomosis of the colon to the proximal end of this pouch can be performed at a later date. Percutaneous drainage of such an abscess may be appropriate in some cases of diverticulitis, but not in the presence of free peritoneal air. The affected colon needs to be resected emergently in this setting, given the likelihood of a free colonic perforation. Resection of the diseased colon is sufficient in this setting without the need for a total colectomy.
19–A. Metastatic neoplasms most often originating from the colon, breast, or lung are the most common etiology of malignant liver tumors, while hepatocellular carcinoma is the most common primary malignant lesion of the liver. Worldwide, the most common cause of hepatocellular carcinoma is cirrhosis secondary to hepatitis B infection. α-Fetoprotein is a tumor marker for hepatocellular carcinoma, although it is nonspecific, with elevations also noted in patients with liver metastases, teratocarcinomas, yolk sac tumors, and even cirrhosis. Hepatoblastomas are characteristically very sensitive to chemotherapy.
20–A. Hypersplenism will occasionally occur in patients with acquired immunodeficiency syndrome (AIDS). Criteria for splenectomy are the same for patients with human immunodeficiency virus (HIV) as for those without it. Symptomatic splenomegaly (i.e., hypersplenism) caused by a condition which is otherwise not reversible is an indication for splenectomy. Emergent splenectomy, however, is not indicated. Ideally, this patient would be given the appropriate vaccinations against encapsulated organisms 10 days before the splenectomy. Plasmapheresis would be of no benefit in this patient. Intravenous (IV) gamma globulin is a medical therapy given to patients with idiopathic thrombocytopenic purpura (ITP). Splenic artery embolization is not indicated for the treatment of hypersplenism.
21–B. Thyroid storm generally presents in patients with undiagnosed or inadequately treated hyperthyroidism and can be precipitated by manipulation or palpation of the gland. Preventative measures include preoperative administration of β-blockers and propylthiouracil (PTU) until the patient becomes euthyroid. Treatment of an acute presentation of thyroid storm (fever, tachycardia) involves mechanical cooling, administration of oxygen, β-blockers, PTU, and iodide salt solutions (e.g., Lugol's solution or potassium iodide). Administration of a large amount of iodide with uptake into the thyroid effectively inhibits production of triiodothyronine (T3) and thyroxine (T4), resulting in a rapid decrease in serum thyroid hormone levels (Wolff-Chaikoff block).
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Thyroid storm is not related to calcium metabolism, and T4administration is contraindicated in this setting. Dantrolene is used for malignant hyperthermia, which would be unlikely to develop before induction of anesthesia. Administration of blood products is not indicated in this setting.
22–D. An anastomotic leak is a devastating complication. Principles of performing proper anastomoses include ensuring good blood supply to both ends of bowel (colonic anastomoses are at higher risk because of their more tenuous blood supply), creating a tension-free, serosa-to-serosa, watertight apposition with inverted mucosal surfaces, avoiding gross contamination, and avoiding distal obstruction. Some large bowel anastomotic leaks may be well localized with percutaneous drainage of fluid collections or small abscesses serving as appropriate therapy without the need for immediate reoperation. Severe leaks may result in terrible complications, including abscess formation, enterocutaneous fistulas, or diffuse peritonitis, which will require resuscitation and nasogastric aspiration, followed by laparotomy and exteriorization of free bowel ends.
23–A. This patient has choledocholithiasis. She has secondary common duct stones, most likely representing black pigment stones caused by hemolysis from her sickle cell disease. Brown pigment stones are formed from a combination of bile stasis and bacterial deconjugation of bilirubin. Choledocholithiasis commonly presents with a fluctuating history of pain and jaundice. An endoscopic retrograde cholangiopancreatography (ERCP) may be used not only to diagnose a common duct obstruction but also to treat the condition by removing the stone. Because of the multiple stones present in the gallbladder, some surgeons may take such a patient to the operating room for cholecystectomy and intraoperative choledocoscopy with stone extraction.
24–D. All of these complications can occur during placement of a Swan-Ganz (pulmonary artery) catheter. Inappropriate needle placement can result in a pneumothorax or hemothorax. Cardiac perforation and perforation of the pulmonary artery can occur while advancing the catheter through these structures. Although rare, dislodgment of a large venous thrombus during placement can occur, resulting in a pulmonary embolus. However, sudden hypotension and hemoptysis occurring during placement of this catheter suggests rupture or perforation of the pulmonary artery. Immediate recognition of this injury is essential for appropriate treatment because mortality with this injury is high.
25–E. The patient described displays the characteristics of the multiple endocrine neoplasia (MEN) IIA syndrome, which can include medullary thyroid cancer, hyperparathyroidism, and pheochromocytomas. Any patient who presents with medullary thyroid cancer and a history suspicious for the MEN syndrome should be evaluated for a possible pheochromocytoma and parathyroid abnormalities, including urine tests for catecholamines, metanephrines, vanillylmandelic acid, parathyroid hormone, and calcium. Treatment of medullary thyroid cancer involves total thyroidectomy rather than lobectomy because this type of thyroid cancer tends to be multicentric. Patients with the MEN syndrome who present with a pheochromocytoma have a 50% chance of having bilateral adrenal involvement and should thus be approached transabdominally to evaluate both adrenal glands. A laparoscopic approach is not contraindicated in these patients. Parathyroid disease in these patients is almost always diffuse hyperplasia rather than a solitary adenoma.
26–A. For melanomas less than or equal to 1 mm thick, appropriate treatment of the primary lesion involves wide local excision with 1-cm margins. Establishing general guidelines for adequate margins based upon the thickness of the lesion prevents excessive resections that are difficult to close and attempts to prevent local recurrences because of inadequate margins. Mohs' microsurgical technique is contraindicated in the treatment of melanomas because this may not involve en bloc resection of the entire lesion. Cryosurgical ablation is also contraindicated for melanomas because this does not allow for assessment of the depth of invasion of the lesion versus resection.
27–D. The treatment of Hürthle cell tumors of the thyroid is somewhat controversial. In general, like for follicular cell carcinomas, a total thyroidectomy is considered the most appropriate procedure when surgery is performed. Unlike other follicular carcinomas and papillary tumors, the Hürthle cell variant is characteristically resistant to uptake of radioiodine (131I) and thus resistant to 131I ablation therapy. In addition, many advocate formal lymph node dissection when positive nodes are identified. Lobectomy and isthmusectomy is generally considered inadequate resection, particularly for aggressive Hürthle cell tumors.
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28–E. Asymptomatic simple liver cysts generally do not require treatment. There is no associated risk of malignant transformation and the small risk of rupture does not necessitate treatment of such cysts. The walls of simple liver cysts often contain islands of biliary ductal epithelium known as von Meyenburg complexes. Indications for resection or unroofing of the cyst with subsequent oversewing of the cyst wall include symptoms (i.e., pain), rupture, hemorrhage, indeterminate diagnosis, and infection. Initial percutaneous drainage of infected cysts is also an appropriate alternative.
29–C. In patients with the multiple endocrine neoplasia (MEN) II syndrome who present with both medullary thyroid cancer and a pheochromocytoma, the pheochromocytoma should be addressed first. Preoperative treatment with α- and β-adrenergic blockade should be followed by surgical resection. The medullary thyroid cancer should be addressed at a later date with total thyroidectomy. In addition, subtotal parathyroidectomy may be performed if hypercalcemia secondary to parathyroid hyperplasia is identified preoperatively.
30–B. Inadvertent placement of a feeding tube within the airway (e.g., trachea, bronchus) is estimated to occur [asymptotically equal to] 5% of the time when attempting to place nasoenteric tubes in critically ill patients. Although very rare, significant bronchial injury, including perforation with subsequent development of a tension pneumothorax, can occur and must be recognized and treated immediately by removing the feeding tube and placing a chest tube, based on your clinical assessment of the patient. Fluid resuscitation is important but will not address the primary catastrophic event. In this setting, prompt removal of the feeding tube is essential and injection of contrast is foolish. In addition, the initial steps in the management of this patient do not require performing emergent laparotomy or a pulmonary angiogram given the likelihood of the diagnosis based upon the temporal relationship with feeding tube placement.
31–B. Pernicious anemia can result from several pathophysiologic mechanisms. Loss of cells that make intrinsic factor from autoimmune disease results in the inability to absorb the vitamin B12. Loss of the terminal ileum results in malabsorption of vitamin B12, which results in pernicious anemia. Bacterial overgrowth in segments of bowel (e.g., blind loops) may also lead to consumption of the vitamin by the bacteria, with subsequent deficiency. B12 deficiency results in defects in blood cell maturation, as well as peripheral nerve metabolism. Dumping syndrome characteristically occurs after gastric surgery, resulting from disruption of pyloric function or bypass of the pylorus. Ileal resections are not a cause of hypercalcemia. The majority of dietary iron is absorbed within the duodenum; thus, iron deficiency anemia is not a characteristic directly related to ileal resection.
32–C. Infectious mastitis is a relatively uncommon disease, representing a bacterial infection of an obstructed milk duct. Staphylococcus aureus is by far the most common pathogen. It primarily affects women who are breast-feeding. Most cases begin as skin cellulitis, and if caught early, may be treated with antibiotics alone. If caught late in the course, after abscess formation, surgical incision and drainage are required. There is no need to stop breast-feeding with infant-safe agents during antibiotic therapy for infectious mastitis, and some believe that the continued stimulation and drainage may aid in treatment. It is important to keep in mind that whenever a primary infection of the breast is suspected clinically, inflammatory breast cancer must be considered in the differential diagnosis and ruled out. Treating this patient with reassurance, nonsteroidal anti-inflammatory drugs (NSAIDs), or danazol would be ineffective in relieving the breast infection.
33–A. Because the site of bleeding had been isolated in this patient, a segmental resection is possible and will cause less morbidity than a subtotal colectomy. However, if the site of bleeding had not been identified, a subtotal colectomy would be indicated because it is the only way to ensure a curative resection and prevent future bleeding. Angiography with embolization or vasopressin infusion is associated with a high rate of rebleeding and a low but significant risk of bowel perforation. These techniques can, however, be useful alternatives in high-risk patients.
34–B. Infected wounds of the hand are treated by aggressive surgical débridement, open drainage, and wound exploration. During these procedures, foreign bodies are removed and devitalized tissue is débrided. The most common pathogen in human bite wounds is Staphylococcus aureus. Eikenella corrodens is also frequently cultured. Penicillin is generally included in the antibiotic regimen in these wounds, although broad spectrum antibiotics are frequently used initially until culture and sensitivity data are available. Primary closure is never appropriate for
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treating a human bite wound because of the high risk of wound contamination and subsequent infection. Tendon lacerations are repaired secondarily after a minimum of 5–7 days.
35–A. Percutaneous or transrectal drainage of pelvic abscesses is an appropriate alternative to laparotomy for treating localized abscesses, although inability to provide adequate drainage or signs and symptoms of peritoneal involvement may require operative intervention. Without adequate drainage of such an abscess, antibiotics alone would be insufficient therapy. Although antibiotic coverage should be adjusted based on the culture results, initial empiric therapy should be directed against both aerobes and anaerobes. Empiric therapy with antifungal agents has not been demonstrated to provide additional benefit to such patients.
36–D. For elective surgery of intractable ulcer disease (persistence or recurrence of symptoms despite adequate medical therapy) parietal cell vagotomy is frequently preferred among the options listed because of the relatively low morbidity associated with this procedure. Procedures involving a truncal vagotomy are associated with an increased risk of gastric emptying problems versus parietal cell vagotomy. Antrectomy and total gastric resection require disruption of intestinal continuity with formation of new anastomoses, thus resulting in a higher complication rate as well. Unfortunately, parietal cell vagotomy is reported as having the highest ulcer recurrence rate among these options, although in experienced hands this may not be the case.
37–C. A woman of childbearing age with hypotension, abdominal distension, and acute abdominal pain should be suspected of having a ruptured ectopic pregnancy. Complications of Crohn's disease, such as perforation, would generally not present in such an acute manner without a history of previous symptoms. A perforated duodenal ulcer generally would not present with progressive lower abdominal pain, but rather sudden onset of severe epigastric pain and rigidity. Ovarian torsion does not typically cause hypotension. A ruptured appendix can lead to hypotension, abdominal rigidity, and guarding, but this is unlikely to occur in the first 8 hours of abdominal pain.
38–C. Many donor organs come from young, previously healthy individuals who sustain irreversible brain injury. The presence of brain death must be determined before donation as determined by: (1) deep coma without response to painful stimuli, (2) absence of spontaneous respiration in the presence of elevated CO2, (3) absence of movement, (4) absence of brain stem reflexes (e.g., gag reflex), (5) absence of hypothermia, and (6) absence of depressant drugs. Supportive findings include an isoelectric electroencephalogram, absence of intracranial blood flow, or massive cerebral tissue destruction.
39–A. There are four groups, or levels, of axillary breast nodes defined by their relation to the pectoralis minor muscle. An axillary node dissection is the removal of level I, II, and III lymph nodes. It is considered a staging procedure because it has never been shown to directly improve patient outcome. Rather, it is used to direct adjuvant therapies and predict survival. When combined with postoperative radiation to the breast, axillary lymph node dissection is as effective as a modified radical mastectomy. Axillary node dissection without radiation therapy to the breast is associated with a higher local recurrence rate. A simple mastectomy, or subcutaneous mastectomy, removes the bulk of the breast tissue, but provides no information about the axillary node status. A radical mastectomy is the en bloc excision of the breast, the overlying skin, pectoralis major and minor muscles, and the level I, II, and III lymph nodes. For a patient with an early stage breast cancer, this operation is considered too aggressive.
40–A. Chemotherapy is generally indicated in the treatment of stage III colon cancers. This corresponds to Dukes stages C1 and C2. Survival is improved with postoperative adjuvant chemotherapy in these patients. An appropriate chemotherapy regimen would include 5-fluorouracil and levamisole. Chemotherapy is not indicated in stage I lesions; however, current studies are examining the potential benefit in advanced stage II lesions. Radiation therapy is not indicated in the treatment of colon cancer, although it is used in treating rectal cancer.
41–D. A rapid sequence intubation is performed by giving a fast-acting induction agent with a fast-acting paralytic when intubating conditions are desired as quickly as possible. The administration of a paralytic is based on the anesthesiologist's belief after examining the patient's airway that the intubation will be successful. If intubation fails, the patient must be mask ventilated. If the patient can't be mask ventilated, an emergent cricothyrotomy should be performed.
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The safest management is to keep the patient spontaneously ventilating, topically anesthetize the airway, and perform the intubation while the patient is awake. Propofol and thiopental could produce unwanted hypotension in this patient, while etomidate, in theory, could trigger a seizure.
42–E. Pressure sores, or decubitus ulcers, are the bane of postoperative patient care in critically ill, obese, and incapacitated patients. These populations of patients are unable to move on their own and are at high risk of developing pressure ulcers, usually near their sacrum. Prevention is best with early mobilization or frequent position changes. There are numerous methods to treat these ulcers, including special air mattress beds and protective coverings placed over the involved area. Adequate nutrition and proper hygiene also help to prevent sores or to assist in their healing. Wound care to ulcers is best done by daily mechanical débridement (wet-to-dry dressing changes).
43–A. The presence of significant rebound tenderness and guarding suggests the presence of peritonitis probably secondary to rupture of a necrotic, strangulated portion of the intestine. This requires immediate abdominal exploration even after the hernia was able to be reduced. Local wound exploration would not allow for identification and treatment of necrotic bowel. Discharge and elective repair would be inappropriate in the setting of peritoneal signs. Observation would only delay the inevitable.
44–D. A Schatzki's ring is a submucosal, circumferential ring in the distal esophagus that is covered by columnar epithelium on the lower surface and squamous epithelium on the upper surface. Almost all patients with this benign lesion have an associated sliding (type I) esophageal hernia. Gastroesophageal reflux symptoms may be present secondary to the effects of the type I hernia but they often respond to conservative management. The mere presence of a Schatzki's ring in not an absolute indication for surgical intervention when gastroesophageal reflux symptoms are present. A complete work-up including upper endoscopy, manometry, and 24-hour pH probe is warranted before any surgical intervention is considered.
45–D. Although parenteral nutritional therapy can provide for maintenance fluid requirements in some settings, it should not be considered the sole source of hydration in many other settings. Patients with necrotizing pancreatitis can have large volume deficits secondary to third spacing of fluid and aggressive replacement of these deficits with crystalloid, not total parenteral nutrition, should be performed and closely monitored. The severe metabolic acidosis associated with a blood urea nitrogen/creatinine ratio much greater than 20 is consistent with severe volume depletion from inadequate volume resuscitation. This is the most likely source of this patient's current condition.
46–D. Gunshot wounds to the abdomen require performance of an exploratory laparotomy. Although this patient may have been shot in the lateral chest, it is important to recognize that the diaphragm rises to the level of the fourth intercostal space on expiration. Thus, gun shot wounds at or below this level need to have the abdomen evaluated surgically. A subxiphoid window and a sternotomy are not necessary because the injury does not seem to have traversed the “box.” Similarly, an immediate aortogram to evaluate the great vessels is not necessary given the path of injury and the clinical presentation provided.
47–B. Definitive treatment for resectable gastric carcinoma is surgical resection. The generally poor survival associated with gastric adenocarcinoma is due to the advanced stage of most carcinomas at the time of diagnosis. However, surgical resection is curative for lesions confined to the stomach without significant lymph node disease. Currently, radiation and chemotherapy play a minor role in treatment. A gastric bypass procedure is used to treat morbid obesity. In many situations, palliative surgical resection, gastrojejunostomy, or both, may provide temporary relief of symptoms for incurable disease.
48–B. This patient most likely has a small bowel obstruction secondary to adhesions. The first step in the management of this patient should be to insert a nasogastric tube to relieve symptoms and reduce the risk of aspiration of stomach contents. While radiological studies are appropriate, they should not delay the initiation of treatment with a nasogastric tube. Exploratory laparotomy is necessary in a patient with no prior surgical history and no evidence of a paralytic ileus; however, conservative treatment of obstruction caused by adhesions with placement of a nasogastric tube will frequently result in complete resolution of obstructive symptoms. Analgesics
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and antiemetics do not address the primary cause of this patient's symptoms. Continued observation in the emergency room without intervention is not appropriate.
49–B. Hepatic vein occlusive disease, or Budd-Chiari syndrome, is a rare postsinusoidal cause of portal hypertension resulting from occlusion of hepatic venous outflow from the liver. A frequent cause of Budd-Chiari syndrome is thrombotic occlusion. This can often be idiopathic, although hematologic disorders such as polycythemia vera, paroxysmal nocturnal hemoglobinuria, hypercoagulable states, and myeloproliferative disorders may precipitate thrombosis. Other causes include vena caval web formation, infection, trauma, and various tumors including hepatocellular carcinoma, renal cell carcinoma, and adrenal carcinoma.
50–E. Although mivacurium is a nondepolarizing agent, it is also metabolized by pseudocholinesterase. Therefore, use of mivacurium in the setting of pseudocholinesterase deficiency should be avoided. The other agents listed are not metabolized by pseudocholinesterase and therefore would be acceptable alternatives for this patient.
51–E. The initial management of severe symptomatic hyperkalemia involves early administration of Ca2+, which stabilizes the electrical potential of the myocardium to prevent the development of life-threatening arrhythmias. Ca2+ administration does not, however, decrease the K+ levels in the serum. Subsequent measures to decrease serum K+ include administering insulin and NaHCO3, which cause an intracellular shift of K+. Sodium polystyrene sulfonate enemas may also absorb K+ in the colon, preventing recirculation of this pool of K+. Early hemodialysis should also be performed to provide rapid removal of K+ from the serum.
52–D. Intravenous (IV) drug abusers are prone to developing bacterial endocarditis and can subsequently develop splenic abscesses. Gram-positive organisms are most common in these individuals. This patient has several stigmata of endocarditis including the tricuspid systolic ejection murmur and Janeway lesions of the right palm. The abdominal ultrasound demonstrates signs of a splenic abscess. IV antibiotics are absolutely indicated in this patient with bacterial endocarditis. Cardiac catheterization is not indicated with a patient who is hemodynamically stable and has no signs of right-sided cardiac failure. The combination of antibiotics and splenectomy is the most definitive treatment. Occasionally, splenic abscesses can be drained percutaneously, but there should be a relatively low threshold to perform splenectomy. Regardless, percutaneous drainage alone would not be adequate therapy.
53–C. Unlike most other nonsarcomatous lesions, one of the most important prognostic factors for sarcomas is the histologic grade of the tumor. Factors important in grading sarcomas include cellularity, level of differentiation, pleomorphism, necrosis, and number of mitotic figures. Although the age of the patient, lymph node involvement, and location of the lesion all play a role in predicting the rate of recurrence and overall mortality, these factors are generally not as significant as the histologic grade of the lesion.
54–B. Although thyroid nodules are usually benign, all thyroid nodules may potentially represent a malignancy. There are some factors that increase the likelihood of the presence of malignancy in a thyroid nodule. Cystic lesions are almost always benign lesions, though rarely some malignant tumors may develop central necrosis and subsequently appear cystic. The presence of a single nodule is a bigger risk factor for malignancy compared with the presence of multiple nodules, as are seen in benign conditions of the thyroid (e.g., Hashimoto thyroiditis). A history of radiation exposure to the neck significantly increases the risk of malignancy. A family history of multiple endocrine neoplasia (MEN) II syndrome increases the risk of development of medullary thyroid carcinoma. The presence of symptoms associated with a thyroid nodule such as dysphagia or hoarseness is highly suggestive of an invasive malignancy as well.
55–B. This patient's presentation is highly suggestive of a colon cancer that is causing a partial obstruction of the colonic lumen. Among the choices given, the most appropriate initial step in the evaluation of this patient would be a colonoscopy to attempt to identify a potential mass and obtain a tissue diagnosis with biopsy. A barium enema would also be an appropriate test to evaluate the colon with this presentation. Flexible sigmoidoscopy would not allow for visualization of the entire colon and thus would be inadequate in this situation. Laparotomy or laparoscopy could certainly obtain a tissue diagnosis. However, these procedures are unnecessarily invasive in this case, particularly if the lesion is benign or if it is a cancerous lesion amenable to colonoscopic resection.
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56–B. Extra-adrenal sites of chromaffin tissue include the bladder, paravertebral ganglia, the carotid body, and the renal hilum. However, the most common site of chromaffin tissue outside of the adrenal gland is in the organ of Zuckerkandl, which is located at the aortic bifurcation. Any of these sites can harbor an extra-adrenal pheochromocytoma, termed a paraganglioma.
57–D. The current recommendation for local treatment of primary extremity sarcomas larger than 5 cm is wide en bloc surgical excision with postoperative local radiation therapy. Radiation therapy alone is inadequate. Surgical resection alone is generally adequate for lesions smaller than 5 cm. Except for some pediatric sarcomas, chemotherapy has not been shown to provide significant benefit in the treatment of sarcomas. Currently, different types of immunotherapy are being studied for their efficacy in the treatment of sarcomas.
58–B. Unilateral recurrent laryngeal nerve injuries do not result in respiratory compromise and often go unrecognized or may cause hoarseness. Patients with superior laryngeal nerve injury classically develop a weakened voice, which may go unnoticed but may have a significant impact on singers. Bilateral recurrent laryngeal nerve injuries can result in paralysis of the vocal cords in the adducted position, causing airway obstruction and respiratory compromise. After bilateral recurrent nerve injuries, stridor and respiratory distress generally present in the immediate postoperative period following extubation in the recovery room. The diagnosis is unlikely to be delayed for 12 hours in this setting. Hematoma formation from persistent postoperative oozing or frank bleeding can result in delayed airway obstruction and respiratory distress, as described. Treatment involves immediate evacuation of the hematoma at the bedside or in the operating room, depending on the status of the patient. Thyroid storm syndrome would generally present intraoperatively during manipulation of the thyroid gland.
59–D. Hyperaldosteronism (i.e., Conn's syndrome) is a rare disorder characterized by autonomous secretion of aldosterone, causing hypokalemia, expanded blood volume, and hypertension. These fluid and electrolyte disturbances can be attributed to the effect of aldosterone on the distal convoluted tubule, which causes sodium reabsorption in exchange for potassium. Potassium depletion generally causes symptoms of polyuria and polydipsia, and edema is characteristically absent. Women may also have menstrual abnormalities.
60–C. Hepatic adenomas are found predominantly in women of child-bearing age with a distinct positive correlation between oral contraceptive use and the development of adenomas. There is also noted to be a slight increase in patients with diabetes. Frequently, even asymptomatic hepatic adenomas require elective resection because of an approximate 10% risk of malignant transformation, and because of the risk of rupture of these tumors leading to hemorrhage and hypotension or even shock. Occasionally these tumors will regress when oral contraceptives are discontinued, although if regression does not occur, surgical resection is indicated.
61–B. The presentation and pathologic presentation of this patient's breast disease is most consistent with sclerosing adenosis, a histologic subtype of fibrocystic disease. The most common presentation is a cluster of microcalcifications on mammogram without an associated palpable mass or pain. It is the benign breast disease that is most likely to be confused with breast cancer histologically and radiographically. The regularity of nuclei and absence of mitosis are the keys to distinguish it from ductal cancer. Once this diagnosis has been made, reassurance is the only required therapy because sclerosing adenosis does not confer an increased risk of cancer. Additionally, in this patient, with her painful lumpy breasts, close follow-up is probably indicated due to the difficulty of performing self-breast examination. Treatment of pain should first focus on the elimination of known causative agents.
62–E. The detection of pancreatic rejection can be difficult. When performed during the same operation, rejection of a renal graft usually precedes pancreatic rejection, and thus monitoring of serum creatinine is effective in identifying potential pancreatic rejection. Glucose levels often increase after irreversible rejection has occurred. Urinary amylase is useful when bladder anastomosis is present but not for enteric drainage. Fecal and serum amylase levels are not reflective of pancreatic rejection.
63–D. Although early identification of the primary cause of abdominal pain is important, initial management of this patient in shock should be aggressive volume resuscitation. Once his condition is stabilized, a secondary assessment including a detailed history and physical examination
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should be performed to diagnose the nature of the illness. Diagnostic procedures can then be performed based on clinical suspicion.
64–C. All patients with symptoms of gastroesophageal reflux who are being considered for surgical therapy should undergo 24-hour pH probe, endoscopy, and manometry. The pH probe documents acid reflux, endoscopy looks for the pathologic changes of reflux (e.g., Barrett's esophagus, stricture) in the distal esophagus, and manometry evaluates esophageal motility to ensure that the patient can tolerate a fundoplication. This patient has had an adequate trial of medical therapy and has failed. Further attempts at medical therapy are not necessary before proceeding with surgical therapy. Barrett's changes are not cured by surgical intervention but their progression is halted. Foci of adenocarcinoma can still develop within Barrett's mucosa and life-long endoscopic surveillance is needed in these patients.
65–E. Asymptomatic human immunodeficiency virus (HIV)-positive patients undergoing elective operative procedures do not exhibit an increased rate of infection or wound healing complications compared with HIV-negative patients. Appropriate therapy for this patient, as in HIV-negative patients, would include either a modified radical mastectomy or lumpectomy with lymph node dissection and postoperative local radiation therapy, with or without breast reconstruction.
66–C. This lesion may represent the development of a neoplasm (most likely a squamous cell carcinoma) at the site of a previous wound (Marjolin ulcer). The history of a persistent nonhealing ulcer that does not improve with 5 months of local wound care at the site of a previous injury is suggestive of such a lesion. Thus, biopsy of the lesion is essential in the initial management of this patient to rule out malignancy. Cessation of smoking and continued wound care are important in the treatment of this wound, but do not address the issue of a potential malignancy.
67–B. A pancreatic fistula is frequently associated with significant losses of many electrolytes. Pancreatic secretions contain large amounts of Na+, K+, and HCO3- and significant amounts of Mg2+. Hypokalemia refractory to aggressive replacement therapy should raise suspicion for a coexisting hypomagnesemia, which can also precipitate K+ losses. Hypermagnesemia is unlikely in the presence of pancreatic fluid losses, as is hypercalcemia. Hypocalcemia would generally not be associated with the described symptoms. Hyponatremia may rarely be associated with the described symptoms, although refractory hypokalemia is more likely associated with low Mg2+.
68–C. Upper endoscopy is the most reliable method for localizing the source of an upper gastrointestinal bleed. This modality allows treatment of many lesions including peptic ulcer disease and variceal bleeding. For variceal bleeds, one may also use a Sengstaken-Blakemore tube, vasopressin infusion, or somatostatin infusion for temporizing control before definitive treatment. Of significant note, at least 20% of patients with esophageal varices and upper gastrointestinal bleeding will have a gastric or duodenal ulcer as the source of bleeding; hence the value of a full endoscopic examination. Omeprazole therapy alone is not primary in the management of acute upper gastrointestinal bleeding.
69–C. Peutz-Jeghers syndrome is an autosomal dominant familial disease characterized by mucocutaneous pigmentation and intestinal polyposis. The polyps are hamartomas that are most frequently located in the jejunum and ileum but can also be found in the stomach, duodenum, colon, and rectum. It is generally believed that their malignant potential is very low. Peutz-Jeghers syndrome can produce abdominal symptoms caused by intussusception or hemorrhage; as many as one third of patients present with abdominal pain and a palpable abdominal mass as a result of the intussusception. An operation is indicated for abdominal pain or bleeding; it should be limited to conservative resection of involved bowel rather than be an attempt to resect all polyps detected during exploration. While familial polyposis, Gardner's syndrome, and Crohn's disease can cause obstruction, the physical findings of mucocutaneous pigmentation make Peutz-Jeghers syndrome the most likely diagnosis. Human immunodeficiency virus (HIV) enteropathy characteristically presents with malabsorption and diarrhea rather than intussusception.
70–B. Initial management of common duct injuries not detected during surgery is generally conservative. The patient is placed on broad spectrum antibiotics and a combination of external drains and endoscopically or percutaneously placed stents are used to decompress the biliary system. Surgery is delayed because the intense inflammation caused by the leak can make repair
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extremely difficult. Many leaks will resolve with conservative management, but if not, a biliary bypass procedure may be necessary.
71–C. The most common primary hernia in women is an indirect inguinal hernia. Inguinal hernias occur much more frequently in men than in women. Femoral hernias occur more commonly in women than in men, although femoral hernias are not as common in women as are indirect and direct inguinal hernias. Obturator hernias are very rare and do not generally present with a groin mass. Femoral artery aneurysms are also quite rare.
72–C. Urinary tract infections are among the most common nosocomial infections seen and are a frequent cause of postoperative complications. Hesitancy, dysuria, and inability to void are commons symptoms. Positive leukocyte esterase and nitrites as well as cytologic evidence of leukocytes provides strong evidence for an infection. Treatment involves appropriate antibiotic administration. Bilateral ureteral obstruction is rare in this situation and would generally not be associated with such a large amount of urine in the bladder. Infection may contribute to urinary retention and would not be considered “normal” retention. The findings are not consistent with acute renal failure (ARF) or hemorrhagic cystitis.
73–D. Transplant immunosuppression is associated with rapid tumor growth. Patients who undergo curative resection of malignancies should wait at least 2 years (without evidence of recurrence) before undergoing transplantation. Kidney transplantation has been demonstrated to have a better quality of life and decreased mortality compared with continuous ambulatory peritoneal dialysis and hemodialysis.
74–A. This patient suffered either an unintentional subdural or subarachnoid injection with anesthesia above the level of the cervical spine into the central nervous system. Epidural anesthesia requires much larger doses and volumes of local anesthetic to provide the same sensory level of anesthesia as with spinal anesthesia. Therefore, for an epidural, the anesthetic is given in divided doses when bolused in case the catheter migrates out of the epidural space. Subdural cannulation can occur despite correct epidural placement and is only recognized after an unusually high block after a modest amount of local anesthetic. Hypotension and bradycardia secondary to block of the sympathetic chain are likely to result in this setting and must be aggressively treated.
75–E. Hypoglycemia is a frequent complication of acute cessation of parenteral nutritional therapy because the intravenous carbohydrate load is suddenly discontinued. The patient's symptoms and temporal relationship to discontinuation of the parenteral nutrition therapy is consistent with a hypoglycemic event and initial evaluation should involve checking serum glucose before other major steps are taken. All of the other choices may be reasonable management steps in a patient who abruptly becomes unresponsive; however, in the scenario described, serum glucose analysis is the most prudent step in the initial evaluation.
76–D. It is important to note that any skin lesion of this sort can be malignant. However, there are some findings that may provide additional clues to the malignant potential of some lesions. The classic mnemonic (ABCD) of evaluation of skin lesions is a useful initial tool. Findings suggestive of malignancy include Asymmetry in color (multiple shades), Border irregularity, Color variation (multiple colors in same lesion), and Diameter of the lesion (larger lesions are more likely to be malignant). Other factors suggestive of malignancy include nodularity of the lesion, ulceration, itching, bleeding, or lesions that change rapidly over time. Therefore, among the choices, a smooth lesion with consistent coloring throughout is more likely to be benign than the other lesions listed.
77–A, B. Severe epigastric pain radiating to the back, nausea, vomiting, and anorexia are all signs of pancreatitis, although similar symptoms may also be present with cholecystitis or choledocholithiasis. An elevated amylase is commonly found in patients with pancreatitis, while alkaline phosphatase may be elevated in patients with cholecystitis or choledocholithiasis. Identification of multiple gallstones throughout the biliary tree may be associated with pancreatitis or cholecystitis. Other ultrasound findings consistent with cholecystitis include gallbladder wall thickening, pericholecystic fluid, and distension of the gallbladder.
78–E. Suprapubic pain and dysuria are classic signs of urinary tract infection. Leukocyte esterase,
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nitrates, white blood cells, red blood cells, and bacteria on urinalysis are all signs of infection.
79–B. Ultrasound findings associated with cholecystitis include a distended gallbladder, gallbladder wall thickening, pericholecystic fluid, gallstones, and a sonographic Murphy's sign. Alkaline phosphatase is commonly elevated in patients with cholecystitis. Pancreatitis would typically present with pain in the epigastric region; however, pericholecystic fluid would not be a typical finding.
80–C, D. This patient has a biliary stricture caused by previous biliary surgery. Surgical bypass is indicated and a choledochojejunostomy or hepaticojejunostomy may be performed. In these procedures a portion of the jejunum is anastomosed to the common bile duct to permit drainage of bile around the stricture. A ductal anastomosis above the cystic duct is considered a hepaticojejunostomy, while an anastomosis below the cystic duct is considered a choledochojejunostomy. Thus the choice between these two procedures depends on the location and extent of the lesion. Primary reanastomosis of the remaining bile duct is sometimes possible in these situations but biliary enteric bypass procedures are currently preferred in most settings.
81–A. This patient has a lesion in the lower third of the common bile duct, which is highly suspicious for cholangiocarcinoma. Also high on the differential is pancreatic carcinoma. Regardless, the procedure of choice for treating resectable carcinomas in this area is radical pancreaticoduodenectomy (Whipple's operation). This involves resecting the gallbladder, common bile duct, head of the pancreas, duodenum, and perhaps the distal stomach.
82–A. Gastrinomas cause the Zollinger-Ellison syndrome with intractable peptic ulcers and very high serum gastrin levels. Although these tumors are uncommon, this diagnosis should be considered in any patient with refractory peptic ulcer disease.
83–F, G. Both glucagonomas and somatostatinomas may be associated with the development of glucose intolerance and diabetes mellitus. Glucagonomas may also be associated with a characteristic rash called necrolytic migratory erythema. Somatostatinomas may also be associated with steatorrhea and gallstone development.
84–D. Insulinomas are characterized by a marked catecholamine surge because of a profound insulin-induced hypoglycemia. The hypoglycemia frequently worsens with periods of fasting. The catecholamine surge results in diaphoresis, palpitations, and anxiety.
85–F. Glucagonomas are generally characterized by new onset of glucose intolerance or diabetes mellitus and a characteristic rash called necrolytic migratory erythema.
86–A, C. Vasoactive intestinal peptide tumors (VIPomas) are tumors that are associated with the development of profuse watery diarrhea. VIPomas cause the Verner-Morrison, or WDHA syndrome, with watery diarrhea, hypokalemia, and achlorhydria. In addition, although gastrinomas are generally associated with refractory peptic ulcer disease, these tumors frequently present with persistent chronic diarrhea. Approximately 10%–20% of gastrinomas may present with diarrhea as the only symptom.
87–A. This patient most likely has an ectopic pregnancy. Of the choices listed, pelvic inflammatory disease is the most significant risk factor for ectopic pregnancy. Previous ectopic pregnancy and prior tubal manipulation are also significant risk factors.
88–E. This patient has an abdominal aortic aneurysm that is possibly expanding and is at risk for rupture based on the size and the symptoms described. Among the choices listed, only atherosclerosis is a significant risk factor for abdominal aortic aneurysms.
89–C, H. This patient most likely has a sigmoid volvulus. These patients classically present with left lower quadrant pain, distention, and constipation. Plain films usually show closed loop of bowel and may have the classic “bird's beak” abnormality, which is a tapering of the colon where it is twisted. Significant risk factors for sigmoid volvulus include a chronic bedridden state, pregnancy, laxative use, prior surgery, and residence in psychiatric or nursing home facilities.
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90–A, B, C, E. A patient with a right-sided chest wound with decreased breath sounds could have either a tension hemothorax or a tension pneumothorax leading to hypotension. It is also important to recognize the potential risk for liver injury, given the location of the gunshot wounds. Any penetrating injury below the fourth intercostal space warrants exploratory laparotomy to rule out possible abdominal injury. Furthermore, with injuries to this area, cardiac tamponade should be considered as a potential source of hypotension.
91–D. Aortic injury should be suspected in all patients involved in high-speed motor vehicle accidents. A widened mediastinum and loss of the aortic knob are signs of possible aortic arch injury. Other signs on chest radiograph include capping of the left lung or a left sided pleural effusion.
92–B. This patient has all three classic signs of cardiac tamponade—hypotension, muffled heart sounds, and jugular venous distension, or Beck's triad. The presence of all three signs is unusual but often in the presence of hypotension without other obvious causes and with blunt chest trauma, cardiac tamponade should be suspected.
93–H, I. This patient has a documented pelvic fracture confirmed radiographically, which can lead to significant hemorrhage within the pelvis. The patient also has signs of a spinal cord injury, with no movement of her lower extremities and loss of anal sphincter tone characteristic of such an injury.
94–A, E. A hypotensive patient with a chest injury and unilateral decreased breath sounds warrants concern for either a tension hemothorax or a tension pneumothorax as a cause of shock. Tracheal deviation is a characteristic sign that the intrapleural pressure is significantly increased and probably causing impaired venous return to the heart, leading to hypotension. Emergent decompression with chest tube placement should be performed in either case.
95–C. Iatrogenic sources of abnormal bleeding are usually secondary to excess anticoagulation by either heparin or warfarin. Prolonged prothrombin time (PT) is suggestive of over-coumadinization, while a prolonged partial thromboplastin time (PTT) is indicative of excess heparinization. Correction of both may be done acutely with fresh frozen plasma, while vitamin K may also be used to correct an abnormal PT. This patient was relatively stable at the time of the bleeding and this episode followed a session of hemodialysis. Heparin is often used both during hemodialysis to prevent blood clotting in the dialysis machine and to maintain the patency of dialysis catheters while not in use. The only coagulation abnormality noted was a prolonged PTT, indicative of over-heparinization.
96–A, B, F. Disseminated intravascular coagulation is a severe sequelae of trauma, sepsis, or severe hypoxia. Generalized activation of the intrinsic and extrinsic coagulation systems can be caused by many factors including severe trauma and hypotension. Coagulation system activation consumes the available endogenous clotting factors and stimulates the fibrinolytic system. Severe hypothermia can also inhibit coagulation. Rapid administration of fluids and packed red blood cells (PRBCs) with severe blood loss without adequate replacement of platelets and coagulation factors can also lead to significant dilution of coagulation factors and platelets, contributing to such a coagulopathy. Treatment involves early recognition and elimination of the underlying condition, prevention and aggressive treatment of hypothermia, intensive supportive care, as well as rapid administration of fresh frozen plasma, cryoprecipitate, vitamin K, and platelets. Prognosis in this setting is poor.
97–E, F. Renal failure is frequently associated with impairment of platelet function leading to an increased bleeding time even without alterations in prothrombin time (PT) and partial thromboplastin time (PTT). Spontaneous bleeding occurs infrequently with this disorder, although it can lead to significant bleeding intraoperatively. When treatment is indicated, administration of platelets can alleviate symptomatic bleeding. In addition, administering desmopressin can improve function of the patient's platelets in this setting.
98–B, C. Given the normal prothrombin time (PT) and partial thromboplastin time (PTT) with an abnormal bleeding time in a patient with a history of bleeding abnormalities, this patient most likely has a deficiency in von Willebrand factor. This is rarely associated with spontaneous bleeding, although it can be associated with abnormal bleeding after severe injury or surgery.
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The most appropriate treatment of von Willebrand factor deficiency would be cryoprecipitate, which could be given in this situation. Fresh frozen plasma contains a small amount of this factor and could also be used, although in the presence of von Willebrand factor deficiency, cryoprecipitate is preferred.
99–B. Reversing the effects of warfarin therapy requires replacement or regeneration of the anticoagulation factors affected by this therapy (i.e., factors II, VII, IX, and X). Administering vitamin K can reverse the effects of warfarin, although this generally takes 6–12 hours before adequate improvement in coagulation occurs. Fresh frozen plasma is a good source of these key coagulation factors and can be administered in situations in which rapid reversal of the effects of warfarin is necessary.
100–I, J. Patients receiving artificial mechanical valves generally require anticoagulation therapy to prevent thrombus formation on the valve. In this situation, both heparin and warfarin therapy may play a role in such therapy. Initially, heparin therapy can be started to provide rapid anticoagulation until the effects of warfarin become therapeutic, at which time the heparin can be discontinued and the warfarin continued chronically. In patients without protein C deficiency, starting heparin therapy before administering warfarin is essential because warfarin therapy can initially cause an acute increase in protein C function with a procoagulant effect. Thus, heparin provides an anticoagulation effect during this transient period.