Master the board step 3

Gastroenterology
Chronic Diarrhea
Lactose Intolerance
This is probably the most common cause of chronic diarrhea and flatulence.
Diagnose and treat by removing all milk and milk-related products from the
diet except yogurt. A lactose-intolerance test may also be performed.
Carcinoid Syndrome
This is associated with flushing and episodes of hypotension.
Diagnose with a urinary 5-HIAA level. Treat with the somatostatin analog
octreotide.
Inflammatory Bowel Disease
Look for blood, fever, and weight loss. (This is discussed in more detail earlier
in this chapter.)
Malabsorption
This type of chronic diarrhea is always associated with weight loss. Fat malabsorption
is associated with steatorrhea, which leads to oily, greasy stools that
float on the water in the toilet. There is a particularly foul smell to the stool.
The causes of fat malabsorption are as follows:
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Celiac disease (gluten sensitive enteropathy), or nontropical sprue
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Tropical sprue
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Chronic pancreatitis
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Whipple disease
All forms of fat malabsorption are associated with the following:
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Hypocalcemia from vitamin D deficiency, which may lead to osteoporosis
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Oxalate overabsorption and oxalate kidney stones
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Easy bruising and elevated prothrombin time/INR from vitamin K malabsorption
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Vitamin B12 malabsorption from either destruction of the terminal ileum
or loss of the pancreatic enzymes that are necessary for B12 absorption
Diagnostic Testing
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Best initial test: Sudan black stain of stool to test for the presence of fat.
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Most sensitive test: 72-hour fecal fat
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