Internal-Medicine

94 4: Gastroenterology
18. (B) Despite some decline, distal tumors are still
the most common. The fact that up to 60% of
tumors are located in the rectosigmoid is the
rationale for screening via flexible, fiberoptic
sigmoidoscopes. Occult blood testing and
colonoscopy are other possible screening techniques.
(Kasper, p. 529)
19. (E) This pattern of symptoms is characteristic of
afferent loop syndrome. It is caused by distention
and incomplete drainage of the afferent
loop and requires surgical correction. Bacterial
overgrowth of the afferent loop is more
common. Its clinical presentation includes postprandial
abdominal pain, bloating, and diarrhea.
Fat and vitamin B 12
malabsorption can
occur. (Kasper, p. 1757)
20. (B) Pancreatitis in AIDS patients can be caused
by cytomegalovirus and cryptosporidium as
well as M. avium complex. Drugs are another
cause of AIDS-related pancreatitis. (Kasper, p. 1899)
21. (B) Hepatoma is the most likely diagnosis in
this man. In China, it is estimated that the lifetime
risk of hepatoma in people with chronic
hepatitis B is close to 40%. AFP elevations, over
500–1000 mg/L in the absence of a colonic
tumor (or pregnancy), suggest hepatoma.
Paraneoplastic syndromes are not common but
include erythrocytosis, hypercalcemia, and
acquired porphyria. (Kasper, p. 534)
22. (D) Ascitic fluid in uncomplicated cirrhosis
of the liver shows a specific gravity