Answers

1. d—Alkaline phosphatase levels have been found to correlate well with tumor burden and survival. These lesions are half as common as osteogenic sarcomas and usually present with pain, tenderness, and a mass. The mainstay of treatment is radiation therapy and chemotherapy (doxirubicin, cyclophosphamide, vincristine, ifosfamide, etc). Surgery is reserved for control of local disease. Ewing’s tumors generally arise in the femur or pelvis.
    
2. e—None of these findings occur in all patients with primary hyperparathyroidism, and none are necessary for making the diagnosis. Elevated serum parathyroid hormone levels are very common but are not diagnostic in the absence of coexistent hypercalcemia. Half of patients with primary hyperparathyroidism have low serum phosphate levels, but levels rise in those with concurrent renal disease. Hyperchloremic metabolic acidosis oc­­curs in 10% to 40% of patients. The serum alkaline phosphatase is elevated in only those patients with bone disease (< 5%).
    
3. e—The T lymphocyte product, granulocyte-macrophage colony stimulating factor, enhances bone marrow production of granulocytes. Tumor necrosis factor is synthesized by macrophages and monocytes, and its function is described by its title. Interleukin 11 is made by neurons and fibroblasts and increases platelet function. Erythropoietin is made by the kidneys to enhance red blood cell production. Interferon beta, a fibroblast product, increases the expression of class I major histocompatibility complexes.
    
4. d—Inadequate daily intake to meet energy expenditure needs is the most reliable means of documenting malabsorption. Since the circulating half-life of albumin is 14 to 18 days, a low level of this protein is nonspecific. The ratio of exchangeable Na to exchangeable K must exceed 1.2 to diagnose malabsorption. A respiratory quotient of 1.0 represents pure carbohydrate utilization. To be diagnostic of malabsorption, the respiratory quotient must be 0.7 or lower. Malnutrition is diagnosed if the patient has lost more than 10% of his or her body weight.
    
5. a—Early mobilization after operation is the best prophylaxis against deep vein thrombosis. While low-molecular-weight heparin and sequential compression devices decrease the occurence rate of deep vein thrombosis, neither is as effective as early mobilization. There are no data that passive ankle flexion or compressive stockings have any effect on the occurence rate of deep vein thrombosis.
    
6. b—While repair of a totally occluded renal artery might be performed occasionally, this procedure is contraindicated if the kidney is less than 6-cm in size. The remaining manifestations do call for surgical repair.
    
7. c—In the presence of concomitant choledocholithiasis, gallbladder bile is infected in 60% of patients. This percentage is significantly higher in the presence of cholangitis. Biliary tract cultures are rarely polymicrobial, except in cases of cholangitis. Postive bile cultures are more likely with increasing age and biliary tract malignancies. Unfotunately, it is almost impossible to sterilize the gallbladder with antibiotics.
    
8. a—The teens and early twenties are the most common ages for appendicitis, not childhood, as is often discussed. Eighty-five percent of appendicitis cases can be treated successfully with antibiotics, but the disease recurs in 35%. The most common cause of appendicitis is lymphoid hyperplasia. The mortality rate of 7% is correct in the elderly (octagenarians and older), but it is 1% to 2% in younger adults. Leukocytosis occurs in 60% of patients with acute appendicitis, and almost half of the patients with that disease are operated upon with normal white blood cell counts.
    
9. d—With no therapy other than excision, patients with these lesions have a 98% expected disease-free survival rate. No additional therapy is advantageous. Tumors that are 2.1 cm in diameter are T2 lesions. The risk of a second primary is the same in these patients as in the general population.
    
10. c—While never as high as 6%, rates of dehiscence increase with advancing age. Dehiscence is most commonly due to technical errors, and its frequency increases with corticosteroid use. Wound infections facilitate the development of dehiscence by causing tissue necrosis along the wound-closure margins.
     
11. c—Short-segment Barrett's esophagus occurs in 2% to 8% of people who do not have reflux esophagitis. The condition is three times more common in men and induces malignancy in 30% of patients afflicted with the metaplastic disorder. Barrett's esophagus occurs in 10% of patients with ulcerative esophagitis, and although proton-pump-inhibitor therapy stabilizes the disorder so that it does not progress, the abnormality does not regress or disappear.
     
12. d—Anhepatic patients cannot survive for very long, and there are few successful bridges to transplantation. Consequently, primary nonfunction is an emergency. Primary nonfunction is uncommon, occurring after 2% of liver transplants. The cause is usually related to donor factors. Preservation goals are 12 hours, and 24 hours is far beyond the ideal time frame. Primary nonfunction is rarely an immunologic complication, and it can be distinguished from hyperacute rejection.