View Answer

E

36. Which of the following is not associated with an increased incidence of invasive ductal carcinoma of the breast?

A Sclerosing adenosis

B Lobular carcinoma in situ

C Atypical ductal hyperplasia

D Epithelial hyperplasia

E Papillomatosis

View Answer

A

37. With the increasing use of ultrasound, prenatal diagnosis of abdominal wall defects is becoming more common. You are asked to consult a family with this prenatal diagnosis. Which of the following points and discussion is not true?

A Closure may require more than a single operation.

B If gastroschisis is strongly suspected, amniocentesis is essential to rule out chromosomal abnormalities.

C Total parenteral nutrition is frequently used.

D The outcome of this category of patient is related both to the integrity of the gastrointestinal tract or to associated anomalies.

E One of the primary goals of treatment with abdominal wall defects is to protect the exposed contents of the abdomen.

View Answer

B

38. A patient is involved in a high-speed motor vehicle collision. The patient has a GCS score of 7 on arrival. Which of the following is not indicated?

A Emergent intubation

B Placement of an intraventricular catheter

C Nasogastric tube to prevent aspiration

D Spinal cord immobilization

E Urgent CT scan of the brain

View Answer

C

39. Disadvantages of laparoscopy when compared with laparotomy include all of the following except which?

A Difficulty controlling severe bleeding

B Poorer visualization of the operative field

C Greater difficulty placing sutures

D Loss of tactile sensation

E Higher operating room costs

View Answer

B

40. Laparoscopic cholecystectomy is indicated for all of the following conditions except which?

A Biliary dyskinesia

B Initial treatment in patients with severe cholangitis

C Acute cholecystitis

D Symptomatic cholelithiasis

E Biliary pancreatitis

View Answer

B

Directions: The group of items in this section consists of lettered options followed by a set of numbered items. For each item, select the lettered option(s) that is(are) most closely associated with it. Each lettered option may be selected once, more than once, or not at all.

Questions 41–44

Match the correct treatment with each inflammatory or infectious process of the breast.

41. Mastitis

A Surgical drainage

B Excision of sinus tract

C Antibiotics

D Nonsteroidal anti-inflammatory drugs (NSAIDs)

View Answer

C

42. Abscess

A Surgical drainage

B Excision of sinus tract

C Antibiotics

D Nonsteroidal anti-inflammatory drugs (NSAIDs)

View Answer

A

43. Chronic subareolar abscess

A Surgical drainage

B Excision of sinus tract

C Antibiotics

D Nonsteroidal anti-inflammatory drugs (NSAIDs)

View Answer

B

44. Mondor's disease

A Surgical drainage

B Excision of sinus tract

C Antibiotics

D Nonsteroidal anti-inflammatory drugs (NSAIDs)

View Answer

D

Questions 45–49

For each clinical situation, match the appropriate diagnosis.

45. Occurs when there is cross-match incompatibility

A Acute tubular necrosis

B Hyperacute rejection

C Graft versus host disease

D Acute rejection

E Chronic rejection

View Answer

B

46. Usually a temporary condition or poor renal function that lasts from 1–14 days related to preservation, ischemia, and reperfusion of the transplanted kidney

A Acute tubular necrosis

B Hyperacute rejection

C Graft versus host disease

D Acute rejection

E Chronic rejection

View Answer

A

47. Can usually be successfully treated with high doses of immunosuppression, such as methylprednisolone

A Acute tubular necrosis

B Hyperacute rejection

C Graft versus host disease

D Acute rejection

E Chronic rejection

View Answer

D

48. More prevalent in small bowel transplantation than in other organ transplants related to the large amount of lymphoid tissue associated with the graft

A Acute tubular necrosis

B Hyperacute rejection

C Graft versus host disease

D Acute rejection

E Chronic rejection

View Answer

C

49. Slow decline in renal function over months or years resulting from humoral and cellular events that are generally not treatable or reversible

A Acute tubular necrosis

B Hyperacute rejection

C Graft versus host disease

D Acute rejection

E Chronic rejection

View Answer

E

Questions 50–51

For each question, match the appropriate immunosuppressive agent.

50. A calcineurin inhibitor that became the mainstay of immunosuppressive regimens in the 1980s and continues as the basis of many immunosuppressive regimens with toxicities that include hypertension, gingival hyperplasia, and nephrotoxicity

A Corticosteroids

B Tacrolimus

C Cyclosporine

D Antithymocyte globulin

E Mycophenolate

View Answer

C

51. An antimetabolite used as part of triple immunosuppression therapy

A Corticosteroids

B Tacrolimus

C Cyclosporine

D Antithymocyte globulin

E Mycophenolate

View Answer

E

Questions 52–55

Match the gastrointestinal anomaly with the listed statement.

52. While considering a vascular accident, there is an associated finding of cystic fibrosis in a patient with this gastrointestinal problem.

A Malrotation

B Duodenal atresia

C Small bowel (jejunal and ileal) atresia

D Imperforate anus

View Answer

C

53. Although part of the VATER complex (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia, it is associated more commonly with renal malformations.

A Malrotation

B Duodenal atresia

C Small bowel (jejunal and ileal) atresia

D Imperforate anus

View Answer

D

54. Complete intestinal necrosis is the most feared complication.

A Malrotation

B Duodenal atresia

C Small bowel (jejunal and ileal) atresia

D Imperforate anus

View Answer

A

55. There is a high association with trisomy 21.

A Malrotation

B Duodenal atresia

C Small bowel (jejunal and ileal) atresia

D Imperforate anus

View Answer

B

P.606

Answers and Explanations

• 1. The answer is E (Chapter 21, I D 3 a [2] [a]–[c]). Emergency department thoracotomies should only be performed by trained personnel and for specific indications. The best results and the highest salvage rates have been obtained with emergency thoracotomy following cardiac arrest from penetrating injury to the chest (patient E). In general, major blunt trauma (patients A and B) and failed external cardiac massage lasting for 10 minutes (patient D) are relative contraindications. A patient whose heart stops after a gunshot wound to the abdomen (patient C) has likely exsanguinated and will not benefit from an emergency thoracotomy.

• 2. The answer is B (Chapter 21, I D 5 b [4] [c] [iii]). Retroperitoneal hematomas overlying the duodenum and pancreas should be explored. In this case, the pancreas has been transected overlying the vertebral bodies. The optimal treatment for this condition is distal pancreatic resection. The remaining pancreas will provide adequate exocrine and endocrine function. Direct repair of the pancreatic duct and pancreatic tissue would be extremely difficult and likely associated with a high incidence of fistula and infection. Whipple procedure involves resection of the head of the pancreas and the duodenum and is not indicated for this injury. Pancreaticojejunostomy is used for refractory pancreatic fistulas but would not be optimal treatment in this situation. Most pancreatic injuries can be handled by simple sump drainage, provided that they do not involve transection or major pancreatic ductal injury.

• 3. The answer is D (Chapter 21, I C). He receives 4 points for eye opening, 2 for best verbal response, and 5 for best motor response.

• 4–5. The answers are 4-B and 5-A (Chapter 21, II C 2 a, b; Chapter 21, II C 2 a, b). The burn involves approximately 36% of the body surface area (BSA). According to the Parkland formula, 4 mL/kg of body weight/percent BSA burned of lactated Ringer's solution should be administered during the first 24 hours. Half of this amount should be given during the first 8 hours after injury and the remainder over the next 16 hours.

• 6. The answer is D (Chapter 22, III G 3 a–c). This patient has Hodgkin's disease. Involvement of lymph nodes on both sides of the diaphragm with the presence of “B” symptoms (fever, night sweats, and weight loss) makes this stage IIIB. Hodgkin's disease is not a surgical disease. The surgeon's involvement is to establish a diagnosis by biopsy or, in some cases, to assist with staging of the disease. Stage IIIB Hodgkin's disease is treated by systemic chemotherapy. Radiation therapy would be used in some lower-stage lesions. Surgical debulking would not add anything to the treatment. Since the diagnosis has been established, mediastinoscopy would add nothing further in this particular patient.

• 7. The answer is E (Chapter 22, III B 2 a–c). The patient described has left-sided or sinistral portal hypertension secondary to splenic vein thrombosis. Pancreatitis is the most common etiology of splenic vein thrombosis. This patient is an alcoholic, and the calcifications of the pancreas are suggestive of chronic pancreatitis. The small, nodular liver seen on ultrasound is suggestive of cirrhosis, but this diagnosis would be established histologically. In any event, even if the patient has cirrhosis, he would be Child-Turcotte-Pugh (CTP) class A based on his laboratory values and the absence of encephalopathy and ascites. Orthotopic liver transplantation would not be indicated because of the patient's CTP class and his active drinking. A peritoneovenous shunt is sometimes used for the treatment of refractory ascites, which this patient does not have. The occluded splenic vein rules out a distal splenorenal shunt. A mesocaval shunt would decrease portal pressure in the right or portomesenteric aspect of the abdomen, but not on the left side because of the splenic vein thrombosis. Bleeding gastric varices secondary to splenic vein thrombosis is the one instance of portal hypertension that is cured by splenectomy.

• 8–9. The answers are 8-B and 9-A (Chapter 23, II F 2, 3; Chapter 23, IV F 5 a). Although fine-needle aspiration can be performed, it may not be conclusive to warrant further treatment. A core needle biopsy can easily be performed on a mass of this size. Excision is inappropriate in masses larger than 5 cm. Definitive surgical therapy should not be performed until after neoadjuvant chemotherapy is given.

• 10. The answer is D (Chapter 25, II D, E). An obstruction calculus in a patient with a single kidney represents an indication for emergency surgery. Hydration alone is insufficient and may lead to permanent renal impairment. Radiographic studies with intravenous contrast may cause nephrotoxicity with impaired renal function. Percutaneous nephrostomy tube placement should be reserved for cases in which cystoscopy and retrograde pyelography and stent placement fail.

• 11. The answer is A (Chapter 25, III B 1). Bladder stone formation due to urinary stasis is a known sequelae of benign prostatic hyperplasia (BPH), and with severe obstructive symptoms, patients can have bilateral hydroureteral nephrosis and renal failure, commonly known as obstructive azotemia. Recurrent prostatitis is caused by bacterial or nonbacterial infection of the prostate and has no correlation with BPH. Bladder and prostate cancer or organic impotence are not directly associated with BPH.

• 12. The answer is A (Chapter 25, IV D). Renal cell carcinoma is very chemotherapy resistant. A left radical nephrectomy includes the left kidney, adrenal gland, and investing and fascia as well as a regional lymphadenectomy. Removal of tumor thrombus from the inferior vena cava is indicated.

• 13. The answer is D (Chapter 25, IV E 6 a [3], b [3]). Men with metastatic nonseminomatous testicular carcinoma, and in this case with bulky retroperitoneal disease, are best treated initially with systemic chemotherapy. The agents of choice are cisplatin, etoposide, and bleomycin.

• 14. The answer is C (Chapter 25, IV E 5 a). Seminomas are uniquely radiosensitive among testicular tumors. Other nonseminomatous tumors, on the other hand, respond to chemotherapy and are generally radioresistant.

• 15. The answer is B (Chapter 25, VII D 2). The finding of blood at the urethral meatus or an elevated prostate gland suggests a urethral tear. Passage of a Foley catheter may exacerbate a urethral tear. Intravenous pyelogram (IVP) and computed tomography (CT) can detect injuries to the kidney, ureters, and bladder, but not injuries to the urethra. The patient must have a carefully performed urethrogram before any other urologic manipulation.

• 16. The answer is B (Chapter 25, I C; II B 4). The signs and symptoms of the patient suggest a renal infection. Simple pyelonephritis responds well to antibiotic therapy but requires more than 1 day of therapy to prevent recurrences. However, single-day therapy is adequate for bladder infections. Antispasmodics may minimize some of the symptoms of frequency, but bethanechol can be expected to increase such symptoms.

• 17. The answer is C (Chapter 26, I D). Breast reconstruction can be performed either at the time of mastectomy or as a delayed procedure. Timing is not dependent on adjuvant treatment.

• 18. The answer is B (Chapter 26, I B 3 a [2]). Skin grafts are initially held in place by fibrin bonds. Imbibition is from passive movement of nutrient to the graft from the donor tissue. When inosculation, or vascular budding, occurs, the graft turns pink from return of circulation to the graft.

• 19. The answer is A (Chapter 26, I F 1 a). Direct pressure is the best initial way to control bleeding. Blind clamping or ligatures should never be placed, because this may injure underlying nerves. Clamps, cautery, sutures, ligatures, and clips may be necessary, but this should only be performed under a very controlled situation, preferably in the operating room.

• 20. The answer is A (Chapter 26, II E 6 a). Surgical excision remains the definitive treatment for melanoma. All of the other options are adjuvant treatments.

• 21. The answer is E (Chapter 26, I B). Bone denuded of periosteum and tendons does not support skin grafts. These areas require muscle flaps for coverage.

• 22. The answer is D (Chapter 27, VII A 1 b). The patient has symptoms referable to the central nervous system. Her age makes stroke likely. Having had a recent venous thrombosis, she will likely be on anticoagulant therapy. Thus, a hemorrhage should be suspected. There is no information about motor weakness; therefore, the cerebellum is a more likely location than the cerebrum. The vertigo also implicates the cerebellum. The posterior fossa is a very tight compartment, intolerant of mass effects. Uncontrolled hypertension leads to progression of clot size and is the mechanism for rapid symptom progression and death. Even without clot growth, there is a risk for development of hydrocephalus. The patient needs to be evaluated emergently, her blood pressure normalized if elevated, and a CT scan performed to look for the suspected cerebellar hemorrhage. She will then need either surgery or observation in the intensive care unit. Pulmonary embolism is far less likely than stroke and usually presents with dyspnea. Thus, the ventilation/perfusion ([V with dot above]/[Q with dot above]) scan is not indicated. The son is not vomiting, so the food they had shared is unlikely to be causing her symptoms. Droperidol is given intravenously and would be of little use to the patient at home even if all she really needed was an antiemetic.

• 23. The answer is A (Chapter 27, VIII E; IV B 2). The Cushing's response is the combination of bradycardia and hypertension. Metastatic cancers greatly outnumber primary brain neoplasms. Even if only one fifth of cancers cause brain metastases, these still outnumber primary tumors.

• 24. The answer is E (Chapter 27, VIII E 1, 5). Late onset seizure should be considered to be caused by a brain tumor until proved otherwise. CT head scan appearance is only suggestive of etiology; it cannot be fully depended on to distinguish between primary tumors and metastases. Magnetic resonance imaging (MRI) can reveal additional small lesions often not visible on CT. Multiple lesions would suggest metastases rather than primary tumor, as primary parenchymal tumors are usually but not always solitary. A lesion found on chest radiograph suggests a brain metastases since primary brain tumors do not spread to the lungs. If MRI shows multiple lesions, the surgeon can target the safest one for biopsy. If there is only one lesion, suggesting a primary brain neoplasm, its location in the tip of the nondominant hemisphere allows for radical resection.

• 25. The answer is D (Chapter 27, VIII F 4). Younger patients with glioblastomas tend to survive longer than the elderly, and supratentorial location is more common than infratentorial location in adults. The median expected survival for a patient with a glioblastoma is 1 year. Aggressive cytoreductive surgery improves survival. The difficult issue is the postoperative quality of life. Survival is improved by radiation, although the time gained is weeks or months, not years. The tumor was located in the anterior temporal lobe where seizures are a common presentation.

• 26. The answer is B (Chapter 28, II F 3 b). Dislocation of the knee is accompanied by a 30%–33% incidence of injury to the popliteal vasculature (and nerve). A pre- and postreduction neurovascular examination is mandatory, and any suggestion of altered perfusion (ankle-brachial index (ABI) <0.9, decreased pulses, signs of ischemia) requires an evaluation of the vascular supply distal to the knee. Frank tears or intimal injuries can occur. Dislocation of the hip can lead to avascular necrosis of the femoral head, especially if reduction is delayed for longer than 12 hours; however, this injury is not limb threatening. Shoulder dislocation is associated with axillary nerve trauma and rotator cuff tears in older people. Simple (no fracture) elbow or subtalar dislocations tend to be stable following reduction.

• 27. The answer is A (Chapter 28, II B 4 d). Compartment syndrome is common after high-energy trauma, particularly that which has a component of crushing injury. The diagnosis is made clinically by pain out of proportion to that expected from the injury and pain with passive stretch of muscles in the involved compartment. Intracompartmental pressure monitoring can be used to confirm the diagnosis or to make it in an obtunded patient. Femoral angiography would be indicated if vascular injury were suspected. Elevation of the leg can actually exacerbate compartment syndrome by decreasing the arterial inflow pressure if elevation is excessive. Plain radiographs and continued observation are not indicated, because excessive delay in treatment can result in irreversible ischemia. Fasciotomies must be performed to relieve the compartment syndrome.

• 28. The answer is D (Chapter 28, IV A 2 a [3] [d] [i]–[iii]). Primary osteogenic sarcoma occurs most frequently in adolescence and young adulthood and appears most commonly about the knee (distal femur and proximal tibia). The combination of neoadjuvant (before surgery) and adjuvant chemotherapy,

with surgical resection to achieve at least a wide (2-cm cuff of normal tissue) surgical margin, has increased the 5-year diseasefree survival rate to more than 60%. Radiation is not indicated when clean surgical margins are obtained.

• 29. The answer is D (Chapter 29, IV A, B, C, F 7). A primary repair at time of presentation can be undertaken if the defect is less than 2 cm in length. A blind proximal pouch with a distant tracheo-esophageal fistula is the most common type of malformation. There is a 40% incidence of associated anomalies in one or more other organ systems. Decompression of the proximal pouch is important to reduce aspiration. A radiograph can help to demonstrate the anatomy.

• 30. The answer is C (Chapter 30, II D 3 a). Since all laparoscopic procedures have the potential to be converted to laparotomy, preoperative preparation must be as thorough as for open abdominal surgery. The bladder and stomach are decompressed with a urinary catheter and an orogastric tube, respectively, to avoid injury during creation of the pneumoperitoneum. Prophylaxis against deep venous thrombosis is necessary, as risk factors for that condition are inherent in laparoscopy. General anesthesia is needed for the vast majority of advanced laparoscopic procedures; spinal anesthesia cannot achieve a high enough level without respiratory embarrassment.

• 31. The answer is A (Chapter 30, II G 1–4). Physiologic changes associated with carbon dioxide pneumoperitoneum are complex and interdependent, but several generalizations can be made. Pulmonary compliance is decreased from diaphragmatic elevation and increased intra-abdominal pressure. Hypercarbia causes acidosis, not alkalosis. Cardiac output is usually decreased due to decreased venous return, and blood pressure and systemic vascular resistance are increased.

• 32. The answer is C (Chapter 30, III A). Bile duct injuries or bile leaks after laparoscopic cholecystectomy should not initially be managed by surgical exploration. Resuscitation, antibiotics, and appropriate imaging to define the anatomy of the problem are the first steps.

• 33. The answer is E (Chapter 29, II A). Sixty percent of pediatric inguinal hernias are right sided, 30% are left sided, and 10%–15% are bilateral. The male:female ratio is 6:1. Inguinal hernias do not close spontaneously like umbilical hernias and should be repaired when diagnosed. Incarcerated hernias are managed with reduction followed by hydration and repair.

• 34. The answer is D (Chapter 21, I D 5 b [5] [a], [b], [d], [e]; I D 4 a [1] [c]). Multiple trauma patients with hypotension and hypovolemic shock are rarely, if ever, hypotensive secondary to head injury. The treating physician must look for another cause of hypotension, which is almost always blood loss. The blood loss can be from five different areas: (1) external blood loss from lacerations or an open wound (details should be obtained from the rescue workers at the scene of the accident; (2) intrathoracic blood loss; (3) intra-abdominal blood loss; (4) retroperitoneal bleeding almost always associated with pelvic fractures; and (5) bleeding into the thighs secondary to femur fractures, which can cause shock. In the patient described, the closed head injury would be the least likely mechanism for this continued hypotension.

• 35. The answer is E (Chapter 21, II B 1; C 1, 2 c (1), (2); E 3, 4). The patient described is at a high risk for suffering an inhalation injury. Delayed airway obstruction can develop rapidly during the first 24–48 hours after injury. It is best to perform endotracheal intubation early before respiratory problems develop, as later intubation can be difficult. Vigorous intravenous fluid resuscitation is indicated for all patients who have full-thickness burns involving more than 20% BSA. Since urine output must be followed very closely, an indwelling ureteral catheter is mandatory in the management of these patients. Tetanus toxoid with or without hyperimmune immunoglobulin should be given if the patient's tetanus immunization status is not current. Systemic antibiotics are usually not indicated in the initial management of burn patients.

• 36. The answer is A (Chapter 23, III B). Epithelial hyperplasia, atypical ductal hyperplasia, and papillomatosis are proliferative lesions of the breast that carry an increased risk of invasive ductal carcinoma of the breast. Papillomatosis is simply a description of the pattern the cells assume (papillary). Lobular carcinoma in situ of the breast carries an increased risk bilaterally for an invasive breast cancer, which can be ductal or lobular. Sclerosing adenosis is a proliferation of the acini that appear to invade, but it is not a malignant or premalignant lesion.

• 37. The answer is B (Chapter 29, III). The general category of abdominal wall defects consists of gastroschisis and omphaloceles. The primary goal of treatment is to protect the exposed or potentially exposed gastrointestinal tract. This is done either by abdominal wall closure, scarification of the omphalocele sac, or covering with Silastic or silicon material with staged reduction and closure. Although coverage is complete and the gastrointestinal tract is functional, nutrition is usually accomplished by total parenteral nutrition. The outcome for the patient is dictated by the integrity and viability of the gastrointestinal tract (gastroschisis) or associated anomalies (omphalocele). Chromosomal abnormalities may be present in patients with omphaloceles but not with gastroschisis.

• 38. The answer is C (Chapter 27, V C, D). An orogastric tube should be placed until a fracture of the skull base can be excluded. Nasogastric have been demonstrated to enter the skull through basilar fractures. A GCS less than 8 requires intubation and intracranial pressure monitoring. Pinal cord immobilization should be practiced for all trauma patients. A CT scan will greatly aid diagnosis.

• 39. The answer is B (Chapter 30, II C). It is generally agreed that improved visualization of the operative field due to magnification and improved light delivery to remote areas of the abdomen are an advantage of laparoscopy over laparotomy. Difficulty controlling severe bleeding, greater difficulty placing sutures, loss of tactile sensation, and higher operating costs are clear disadvantages of laparoscopy as compared with laparotomy.

• 40. The answer is B (Chapter 30, III A 1, 2). Laparoscopic cholecystectomy is indicated for most symptomatic biliary conditions, including biliary colic, acute cholecystitis, biliary dyskinesia, and biliary pancreatitis, after resolution of pancreatitis. However, initial therapy for cholangitis is hydration, broad spectrum antibiotics, and drainage of the common bile duct. Cholecystectomy is performed at a later time, after resolution of sepsis.

• 41–44. The answers are 41-C, 42-A, 43-B, and 44-D (Chapter 23, III A). Cellulitis of the breast (mastitis) requires treatment with antibiotics to cover staphylococcus and streptococcus infection. An acute abscess requires surgical drainage. A chronic recurrent abscess requires excision of the sinus tract to avoid recurrence. Mondor's disease is a phlebitis of the superficial veins, and although self-limited, treatment with nonsteroidal anti-inflammatory drugs can alleviate the discomfort.

• 45–45. The answers are 45-B, 46-A, 47-D, 48-C, and 49-E (Chapter 24, I G 1). Hyperacute rejection occurs when the serum of the recipient has preformed antidonor antibodies. Before transplantation, the recipient's blood is examined for the presence of cytotoxic antibodies specifically directed against antigens on the donor's T lymphocytes (cross-match test). Hyperacute rejection cannot be treated but can be avoided. Kidney transplants are occasionally associated with a period of acute tubular necrosis, which is a temporary condition thought to be related to conditions that occur during obtaining and preserving the kidney. It occurs rarely in living donor transplants. High doses of immunosuppression—either methylprednisolone or antithymocyte globulin or OKT3—are used to treat acute rejection. This diagnosis is usually made via the detection and workup of graft dysfunction and may include a biopsy. Acute rejection can be treated and is reversible. Chronic rejection usually has an insidious onset and is multifactorial, involving both cell-mediated and humoral arms of the immune system. In lung transplantation, it is known histologically as bronchiolitis obliterans. Generally, there is no known effective therapy. Because the small bowel is rich in lymphoid tissue, graft versus host disease has become more prevalent in this group of recipients than in other organ transplants. This is caused by the proliferation of donor-derived immunocompetent cells with a number of clinical presentations, including skin rash.

• 50–51. The answers are 50-C and 51-E (Chapter 24, I H 4 a). Calcineurin inhibitors block the calcineurin-dependent pathway of helper T-cell activation and include cyclosporine and tacrolimus, which are both used in maintenance immunosuppressive regimens. Cyclosporine became

the mainstay of immunosuppressive regimens in the early 1980s and is now in a new formulation known as Neoral. Associated side effects include nephrotoxicity, hypertension, tremor, and hirsutism. Tacrolimus, which was introduced more recently, is also a profound inhibitor of T-cell function, with many similar side effects as cyclosporine. Corticosteroids inhibit all leukocytes and have numerous side effects, including excessive weight gain, diabetes, and cushingoid facies. Mycophenolate is an antimetabolite that impairs lymphocyte function by blocking purine biosynthesis via inhibition of the enzyme inosine monophosphate dehydrogenase.

• 52–55. The answers are 52-C, 53-D, 54-A, 55-B (Chapter 29, V A 3). Gastrointestinal anomalies vary greatly. The difference between duodenal atresia and the other small bowel atresias is a developmental (duodenal) accident versus a vascular accident (jejunum and ileum). Therefore, chromosomal abnormalities (most commonly, trisomy 21) appear with duodenal problems. The exception to this general rule is the associated incidence of cystic fibrosis with small bowel atresias. Malrotation, although it causes an obstruction, may also pose a vascular problem. This is related to the midgut volvulus, which can cause total ischemia to the intestine. Renal malformations occur in 40% of the imperforate anus, either as a VACTERL (Chapter 29 IV B 2) complex or related to the disease itself (urethral fistula).