Diseases

Carcinoid Syndrome (Carcinoid Tumour)

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Carcinoid syndrome is a paraneoplastic syndrome comprising the signs and symptoms that occur secondary to carcinoid tumors. The syndrome includes flushing and diarrhea, and less frequently, heart failure, emesis and bronchoconstriction. It Is caused by endogenous secretion of mainly serotonin and kallikrein.

The carcinoid syndrome occurs in approximately 5% of carcinoid tumors and becomes manifest when vasoactive substances from the tumors enter the systemic circulation escaping hepatic degradation. Interestingly, if the primary tumor is from the gi tract (hence releasing serotonin into the hepatic portal circulation), carcinoid syndrome generally does not occur until the disease is so advanced that it overwhelms the liver's ability to metabolize the released serotonin.
flushing: the most important clinical finding is flushing of the skin, usually of the head and the upper part of thorax.
diarrhea: when the diarrhea is intense and explosive, it may lead to electrolyte disturbance and dehydration.
abdominal pain: due to desmoplastic reaction of the mesentery or hepatic metastases.
bronchoconstriction, which may be histamine-induced, affects a smaller number of patients and often accompanies flushing.
secondary restrictive cardiomyopathy: about 50% of patients have cardiac abnormalities classically of the restrictive-type caused by serotonin-induced fibrosis of the valvular endocardium, notably the tricuspid and pulmonary valves, called cardiac fibrosis. This results in a heart with normal rhythm and contractility, but reduced preload and end-diastolic volume. "tips" is an acronym for tricuspid insufficiency, pulmonary stenosis (fibrosis of tricuspid and pulmonary valves).
nausea and vomiting