Carcinoid tumours are neuroendocrine tumours originating from enterochromaffin cells [GIT(~90%), gonads and bronchus mainly]

Some patients develop Carcinoid Syndrome, where the tumour secretes neuropeptides into systemic circulation

Usually they undergo firstpass metabolism in liver

If the patient is becoming symptomatic, due to the neuropeptide secretion, it’s either due to their production in large amounts to overwhelm the metabolic capacity of the liver or that they are released without going through the portal circulation

They secrete bio-active compounds like serotonin, histamine, catecholamines, bradykinin, kallikrein, substance-P, motilin etc

This can cause symptoms like bronchospasm, hypotension, hypertension, flushing etc

Pharmacologic treatment of intraoperative/ acute/ hemodynamic crises are with i.v. Octreotide, whereas for treatment of chronic symptoms, Somatostatin analogues like Lanreotide are used. Octreotide can also be used for prophylaxis. Should be continued postoperatively.

Vasoactive drugs like catecholamines and histamine releasing drugs like morphine, atracurium, succinylcholine, thiopentone etc should be avoided. Use of a test dose may reduce adverse events.

Antihistamines are also given prophylactically in case of gastric tumours

Another concern for the anesthesiologist in such patients is the possibility of Carcinoid heart disease. Here, the patient develops thickened valves resulting in tricuspid and pulmonary regurgitation and pulmonary stenosis (mitral and aortic insufficiency can also occur; but are less frequent). Pericarditis or myocardial metastases can also occur.