A 45-year-old man presents to a physician because of severe chronic diarrhea accompanied by a 18 kg (40 Ib) weight loss. The diarrhea began several years ago, and has become steadily worse. It is often accompanied by excessive flatulence, and the man notes that his stools usually float. The man additionally has felt generally poorly and sometimes has experienced joint symptoms. Intestinal biopsy demonstrates
Iarge numbers of foamy macrophages distending the lamina propria. A periodic acid-Schiff (PAS) stain shows granules within the macrophages.
Q 1
Which of the following is the most likely diagnosis?
/ A. Celiac sprue
/ B. Intestinal lymphangiectasia
/ C. Lactase deficiency
/ D. Tropical sprue
/ E. Whipple disease
Q2
This patient disease has been etiologically related to infection with which of the following?
/ A. Bartonella
/ B. Borrelia
/ C. Francisella
/ D. tropheryma
/ E. Vibrio
Q3
Excessive flatulence suggests which of the following problems :
/ A. Colon obstruction
/ B. GI hypermotility
/ C. GI hypomotility
/ D. Malabsorption
/ E. Small intestinal obstruction
Q 4
BIood studies on this patient demonstrate a microcytic hypochromic anemia. The nutrient whose deficiency would most likely account for the patient's anemia is primarily absorbed in which of the following sites?
/ A. Colon
/ B. Duodenum
/ C. Esophagus
/ D. IIeum
/ E. Stomach
Q 5
This patient's illness is most effectively treated with which of the following?
/ A. Antibiotics
/ B. Chemotherapy
/ C. Radiation therapy
/ D. Steroid therapy
/ E. Surgery
Diarrhea Case 6 Answers
A1
The correct answer is E. This patient has Whipple disease, which is a rare illness characterized by diarrhea, often severe malabsorption, and weight loss. The condition most commonly affects men aged 30 to 60. The disease may present either abruptly or insidiously. If it develops insidiously, non-gastrointestinal manifestations may bring the patient to medical attention. These may include pleuritic pain, pleural effusion, anemia, joint problems, cardiac problems, neuropsychiatric problems, eye problems, or hepatic dysfunction.
All of the other diseases listed can also cause chronic diarrhea.
Celiac sprue (choice A) shows villous atrophy on biopsy, and is related to gluten sensitivity.
Intestinal lymphangiectasia (choice B) shows dilated lymphatic channels on biopsy.
Lactase deficiency (choice C) is due to an enzymatic abnormality and is characterized by a histologically normal intestinal epithelium.
Tropical sprue (choice D) usually shows moderate broadening and shortening of villi, and an often intense inflammatory reaction.
A2
The correct answer is D. Electron microscopy of the intestinal mucosa shows that the PAS-positive granules in macrophages in Whipple disease are actually bacterial forms. The causative organism is Tropheryma whippelii, and, if necessary, its DNA can be identified with PCR technology. This is necessary because attempts to culture the organism have not, to date, been successful. At the moment, this test is available only through reference laboratories. In patients who have extraintestinal manifestations, macrophages containing the bacteria may be found in extraintestinal sites.
Bartonella(choice A) species can cause cat scratch disease, trench fever, and disseminated infections.
Borrelia(choice B) causes Lyme disease.
Francisella(choice C) causes tularemia.
Vibrio(choice E) causes cholera and other diarrheal illnesses.
A3
The correct answer is D. When a patient complains of excessive flatulence, the first step is to ask them to describe the amount and frequency of the flatulence, since some people with normal intestinal gas production have unrealistic expectations about the possibility of completely eliminating flatulence. In cases in which excessive flatulence really is present, you should think of gastrointestinal disorders that can cause malabsorption, since many cases of excessive flatulence are related to bacterial digestion of unabsorbed nutrients (notably carbohydrates) with resultant gas production as a by-product. These disorders may include a wide variety of underlying conditions including pancreatic disease, liver disease, genetic enzymatic abnormalities of the intestinal mucosa, and acquired intestinal tract disease.
Colonic obstruction (choice A), small intestinal obstruction (choice E), and GI hypomotility (choice C) can also cause gas to be retained in the bowel and be visible on abdominal x-ray films, but do not, by themselves, increase gas production.
GI hypermotility (choice B) often accompanies acute diarrheal illness, but the excessive flatulence that may also be present in that setting is secondary to malabsorption rather than the hypermotility.
A4
The correct answer is B. Microcytic, hypochromic anemia suggests iron deficiency. Patients with Whipple disease frequently develop anemia related to poor duodenal absorption of either folate (producing a macrocytic anemia) or iron. Other substances absorbed in the duodenum include water, calcium, fats, sugars, proteins, many vitamins, magnesium, and sodium.
The colon (choice A) absorbs water and electrolytes.
The esophagus (choice C) does not absorb nutrients.
The ileum (choice D) can absorb bile salts, vitamin B12, and chloride.
The stomach (choice E) can absorb water and alcohol.
A5
The correct answer is A. The symptoms of Whipple disease often dramatically improve after antibiotic therapy, although the therapy must often be continued for prolonged intervals to prevent relapse and the microscopic intestinal changes may not resolve for 2 years. Many antibiotics are effective, including chloramphenicol, tetracycline, ampicillin, penicillin, and trimethoprim-sulfamethoxazole. The other therapies listed in the choices are not usually employed with Whipple disease.
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