Cause of massive diarrhea may be a rare disease!
A VIPoma is a rare type of pancreatic tumor that produces vasoactive intestinal peptide (VIP), a substance that causes severe watery diarrhea. About 50 to 75% of these tumors are cancerous. In about 6% of people, VIPoma occurs as part of multiple endocrine neoplasia.
VIPomas are usually diagnosed in middle-aged adults or in young children. Tests used to diagnose a VIPoma may include blood tests (including VIP level), imaging studies such as a CT scan or MRI, and examination of a stool sample. Unfortunately, even though these tumors are slow-growing, the majority of VIPomas are metastatic (have spread to other parts of the body) at the time of diagnosis. The underlying cause of VIPomas is not yet known.
The major symptom is prolonged massive watery diarrhea. People produce 1 to 3 quarts (1,000 to 3,000 milliliters) of stool per day, causing dehydration. In 50% of people, diarrhea is constant, and in the rest, the severity of diarrhea varies over time.
Because diarrhea removes many of the body's normal salts, people often develop low blood levels of potassium (hypokalemia) and excessively acidic blood (acidosis). These changes can cause lethargy, muscular weakness, nausea, vomiting, and crampy abdominal pain. Some people have flushing.
Management typically first involves treating dehydration with fluids and correcting the imbalance of hormones and other substances (metabolic abnormalities) in the body. Medications such as octreotide and lanreotide can usually stop the diarrhea and inhibit the secretion of VIP. Surgery typically follows in order to remove the tumor. When there is no evidence of metastasis, complete removal of the tumor is the only possible cure. The majority of metastatic cases will not be cured by surgery, but symptoms may be managed and prolonged survival is often possible due to the slow-growing nature of these tumors. Targeted therapy or chemotherapy may also be used for people with progressive, advanced disease. The median survival of people with VIPomas is 96 months, but long-term survival mainly depends on the tumor grade, staging, and whether all or most of the tumor can be removed.
Dr. Rakesh Rai. MS, FRCS, MD, CCT, ASTS Fellow.