Monday, September 8, 2008

Very Important

A 40 year old woman presents with months of diarrhea. Even when fasting, the stool volume is >700 mL/day; it averages 3 L/day. You hate to ask, but you learn the stool is tea-colored and odorless. There is no abdominal pain, but she gets some flushing, lethargy, nausea, vomiting, muscle weakness, and muscle cramps. Labs show a low potassium. A stool analysis shows an osmotic gap of 30 mOsm/kg (normal 50-125).

Challenge: What's the diagnosis?


Alex said...

nice poem; VIPoma

Craig said...

Very Important

This is a VIPoma which secretes vasoactive intestinal polypeptide. The tumor is usually in the tail of the pancreas and metastatic at time of discovery. It is characterized by watery secretory diarrhea (supported by the low osmolal gap), hypokalemia, and hypochlorhydria. Serum VIP is >75 pg/mL. Treatment involves replacement of fluids and electrolytes with octreotide, a somatostatin analogue that decreases VIP secretion.

Source: UpToDate.