Carcinoid syndrome commonly presents with flushing and diarrhea. Other clinical features include wheeze, palpitations, telangiectasia, and abdominal pain.
Symptoms develop due to secretion of serotonin, kinins, and other biogenic amines from functional secretory neuroendocrine tumors.
Diagnosed by elevated levels of urinary 5-hydroxyindoleacetic acid. Chromogranin A is often elevated in the presence of liver metastases.
Treatments include medical therapies (somatostatin analogs, radionuclide therapies) and surgical options (resection of primary and secondary tumors).
Complications include carcinoid heart disease and carcinoid crisis at times of stress (e.g., during surgery).
Carcinoid syndrome occurs due to release of serotonin (5-hydroxytryptamine) and other vasoactive peptides into the systemic circulation from a carcinoid tumor. A total of 20% to 30% of midgut neuroendocrine tumors (NETs), 5% of bronchial carcinoid tumors, and approximately 1% of pancreatic NETs secrete 5-hydroxytryptamine and other peptides. In patients with these tumors, carcinoid syndrome develops. The principal features of carcinoid syndrome are diarrhea and flushing. Wheezing, telangiectasia, and abdominal pain can also occur.
History and exam
Key diagnostic factors
Other diagnostic factors
- abdominal cramps
- signs of right heart failure
- cardiac murmurs
- abdominal masses
- genetic multiple endocrine neoplasia type 1 (MEN-1) syndrome
1st investigations to order
- serum chromogranin A/B
- urinary 5-hydroxyindoleacetic acid
- metabolic panel
- liver function tests
- complete blood count
Investigations to consider
- CT chest, abdomen, and pelvis with dual-phase liver
- somatostatin receptor scintigraphy ± somatostatin single photon emission CT (SPECT)
- iodine I-123 metaiodobenzylguanidine (MIBG) scintigraphy
- PET scan
Rajaventhan Srirajaskanthan, BSc (Hons), MD (Res), FRCP
Neuroendocrine Tumour Unit
Kings College Hospital
RS has received research grants from AAA, Novartis and Ipsen, and has given consultancy advice to Pfizer and Ipsen. RS has engaged in the speaker's bureau for AAA, Ipsen, and Mylan.
Martyn Caplin, BSc, DM, FRCP
Consultant in Hepatobiliary and Gastroenterology
Neuroendocrine Tumour Unit
Royal Free Hospital
MC is on the advisory boards for Novartis, Ipsen, Lexicon, and Pfizer; he has also received speaker honoraria from them.
Wail Malaty, MD
Department of Family Medicine
University of North Carolina
Assistant Program Director
MAHEC Rural Family Medicine Residency
WM declares that he has no competing interests.
Rajesh K. Garg, MD
Instructor in Medicine
Brigham and Women's Hospital
Division of Endocrinology
Diabetes and Hypertension
RKG declares that he has no competing interests.
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