hormonal and metabolic disorders
Carcinoid Tumors and Carcinoid Syndrome
Diagnosis
Urine testing for 5-hydroxyindoleacetic acid Sometimes imaging to locate a tumor When symptoms lead a doctor to suspect a carcinoid tumor, the diagnosis can often be confirmed by measuring the amount of 5-hydroxyindoleacetic acid (5-HIAA)—one of the chemical byproducts of serotonin—in the person’s urine, which is collected over a 24-hour period. For at least 3 days before undergoing this test, the person refrains from eating foods that are rich in serotonin—bananas, tomatoes, plums, avocados, pineapples, eggplants, and walnuts. Certain drugs, includingguaifenesin(found in many cough syrups),methocarbamol(a muscle relaxant), and phenothiazines (antipsychotics), also interfere with test results. People who are taking any drugs, particularly one of these, should discuss with their doctor before collecting urine for this test. Other causes of flushing, such as Menopause or alcohol ingestion, need to be excluded. This can usually be done by asking the person questions (such as their age and about their alcohol use), but sometimes testing is necessary. Sometimes when the diagnosis is not certain, doctors give the person a drug to try to induce flushing (called a provocative test), but this method is rarely used and must be done with care. Different tests are used to locate carcinoid tumors. These tests include Computed Tomography (CT) (CT), Radionuclide Scanning or scanning is another useful test. During this test, a substance containing a radioactive tracer is injected intravenously into the body and collects in a particular organ. Most carcinoid tumors have receptors for the hormone 