Carcinoid syndrome is a disorder that occurs when small tumors (carcinoid tumors) make chemicals that get into the bloodstream. The chemicals cause various symptoms. These slow-growing tumors are mainly found in the gastrointestinal tract or lungs (bronchi). They occur in the appendix (most often); small bowel (20%); rectum (15%); bronchi (12%); esophagus, stomach, and colon (10%); and ovary, biliary tract, and pancreas (3%). People usually find out about the disorder when the tumors are very advanced and cause symptoms. This syndrome is rare and occurs in about 3 in 100,000 people.
Carcinoid tumors can make chemicals called serotonin, bradykinin, and histamine. Tumors grow from special cells called neuroendocrine cells. The cause of the tumors isn’t clear.
The main symptoms are skin flushing (75% to 90%), diarrhea, breathing problems, facial skin lesions, and at times, rapid heartbeat. Red-purple flushes usually start in the face and spread to the neck and upper trunk. Flushing lasts from a few minutes to hours. Flushes that last longer may be related to bronchial carcinoids. Emotion, alcohol, or foods may trigger flushes, but flushes may occur without warning. Dizziness, fast heartbeat (tachycardia), and low blood pressure (hypotension) may occur with flushing. Diarrhea occurs in more than 70% of people. It’s often related to bloating of the abdomen (belly). Breathing problems include contraction of smooth muscles in the bronchi (bronchospasm). The result is shortness of breath and wheezing.
The health care provider makes a diagnosis from the medical history, physical examination, chest X-rays, computed tomography (CT) of the abdomen, and laboratory tests. These tests measure levels of the chemicals produced by the tumor. Some foods and drugs can cause false higher levels. Bananas, pineapples, eggplant, avocados, and walnuts can do this. Drugs that can cause false elevations include acetaminophen, caffeine, guaifenesin, and reserpine. Before this test, people must have a restricted diet and avoid these drugs. Special tests may include using radioactive iodine to label somatostatin to find tumors. The health care provider may suggest seeing a specialist such as an endocrinologist and endocrine surgeon.
Treating the syndrome means treating the tumor. Surgery may be done to remove the tumor. If surgery can’t remove widespread tumors, medicines may shrink tumors and control symptoms. These drugs include octreotide and interferon alfa. Hepatic artery embolization and heating or freezing tumor cells may be treatment options in some patients.
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