|Values are valid only on day of printing.|
Detection of vasoactive intestinal polypeptide producing tumors in patients with chronic diarrheal diseases
Vasoactive intestinal polypeptide (VIP) was originally isolated from porcine small intestine and was recognized by its potent vasodilator activity. This brain/gut hormone has widespread distribution and is present in neuronal cell bodies localized in the central nervous system, digestive, respiratory, and urogenital tracts, exocrine glands, and thyroid and adrenal glands. VIP has a wide scope of biological actions. The main effects of VIP include relaxation of smooth muscle (bronchial and vascular dilation), stimulation of gastrointestinal water and electrolyte secretion, and release of pancreatic hormones.
VIP-producing tumors (VIPomas) are rare; most (90%) are located in the pancreas. Watery diarrhea, hypokalemia, and achlorhydria are key symptoms.
Values >75 pg/mL may indicate the presence of an enteropancreatic tumor causing hypersecretion of vasoactive intestinal polypeptide (VIP).
Values >200 pg/mL are strongly suggestive of VIP-producing tumors (VIPoma).
VIPoma is unlikely with a 24-hour stool volume <700 mL.
This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive samples received in the laboratory will be held and assayed after the radioactivity has sufficiently decayed. This will result in a test delay.
1. Ghaferi AA, Chojnacki KA, Long WD, et al: Pancreatic VIPomas: subject review and one institutional experience. J Gastrointest Surg 2008 Feb;12(2):382-393
3. Smith SL, Branton SA, Avino AJ, et al: Vasoactive intestinal polypeptide secreting islet cell tumors: a 15-year experience and review of the literature. Surgery 1998 Dec;124(6):1050-1055 (Review)