(Werner-Morrison syndrome)
VIPoma is a non-pancreatic ?-islet cell tumor, the vasoactive intestinal peptide (VIP) secreting and leads to a complex of symptoms with aqueous diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). The diagnosis is made based on the VIP serum level. The tumor is localized by means of CT and endoscopic ultrasonography. Treatment consists of resection.
The VIPom is an endocrine pancreatic tumor (Endocrine pancreatic tumors), which develops from islet cells. 50-75% of these tumors are malignant, some of the time of diagnosis rather large (7 cm). At about 6% the Vipom occurs as part of multiple endocrine neoplasia on (overview of multiple endocrine neoplasia).
VIPoma is a non-pancreatic ?-islet cell tumor, the vasoactive intestinal peptide (VIP) secreting and leads to a complex of symptoms with aqueous diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). The diagnosis is made based on the VIP serum level. The tumor is localized by means of CT and endoscopic ultrasonography. Treatment consists of resection. The VIPom is an endocrine pancreatic tumor (Endocrine pancreatic tumors), which develops from islet cells. 50-75% of these tumors are malignant, some of the time of diagnosis rather large (7 cm). At about 6% the Vipom occurs as part of multiple endocrine neoplasia on (overview of multiple endocrine neoplasia). Symptoms and complaints The main symptoms are prolonged, solid and aqueous diarrhea (fasting stool volume of> 750 to 1000 ml / day and non-fasting volume up to> 3000 ml / day) and symptoms of hypokalemia, acidosis and dehydration. In half of the patients, the diarrhea is constant; in the other the severity of diarrhea in the course changes. In 33% of patients diagnosed with diarrhea <1 precedes, but 25% have diarrhea ? 5 years prior to diagnosis. Lethargy, muscle weakness, nausea, vomiting, and crampy abdominal pain are common. In 20% of patients during diarrhea attacks a flush occurs similar to that of the carcinoid syndrome. Diagnostic confirmation of secretory diarrhea VIP serum levels endosonography, PET or scintigraphy for localization The diagnosis requires the demonstration of a secretory diarrhea (Stuhlosmolalität is close to the plasma osmolality and two times the sum of the chair concentration of Na and K corresponds to the total measured Stuhlosmolalität). Other causes of secretory diarrhea, v. a. Laxative abuse must be excluded (diarrhea). In these patients, VIP serum levels should be determined (ideally during a diarrhea attack). Significantly increased levels confirm the diagnosis, but mild elevations may also occur in short bowel syndrome and inflammatory diseases. In patients with elevated VIP levels studies on the tumor location as an endoscopic ultrasound, PET and octreotide scintigraphy or angiography for metastasis localization should be encouraged. The electrolytes and blood counts should be determined. Hyperglycemia and glucose intolerance occur at ? 50% of patients. Hypercalcemia occurs in half of patients. Treatment fluid and electrolyte replacement octreotide Surgical resection for localized disease Initial fluid and electrolytes must be replaced. Bicarbonate must be given to replace the defecation-related loss to prevent acidosis. Because with rehydration the loss of water and electrolytes increase with bowel movements, a continuous intravenous replacement can be difficult. Octreotide usually controls diarrhea, but it can be required high doses. Responsively patients can benefit from a monthly administration of 20-30 mg i.m. benefit of a long-acting Octreotidpräparates. Patients often have to take additional Octreotidmedikation pancreatic enzymes because octreotide inhibits the secretion of pancreatic enzymes. In 50% of patients with a localized tumor resection is curative. In patients with metastatic tumor resection all visible tumor tissue can lead to a temporary symptom control. The combination of streptozotocin and doxorubicin can reduce the diarrhea and the tumor mass, if an objective response occurs (50-60%). Newer chemotherapies that are studied in VIPom include temozolomide-based regime, everolimus or sunitinib. Chemotherapy is not curative. Key points More than half of VIPomas is malignant. Intensive aqueous diarrhea (often 1-3 l / day) are common, which often leads to electrolyte abnormalities and / or dehydration. In patients with confirmed aqueous diarrhea VIP serum levels should be measured (ideally during a diarrhea attack). The tumor location by means of endoscopic ultrasonography, PET, octreotide scintigraphy or angiography. If possible tumors should be resected surgically, the diarrhea is suppressed with octreotide.