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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

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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

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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).