Hematology/Oncology

Carcinoid syndrome: Mechanism of action

Carcinoid tumors are rare neuroendocrine tumors which originate most often in the bowel, less commonly in the lungs, and rarely in the reproductive tract.

Carcinoid syndrome will occur in a small percentage of patients  (~10%).

Symptoms include:

  • Facial flushing
  • Abdominal cramps and diarrhea
  • Bronchospasm
  • Palpitations
  • Shortness of breath

MECHANISM: Tumor-derived 5-HTP metabolites, such as serotonin, akinins, and prostaglandins entering systemic circulation cause these symptoms.

Carcinoid syndrome is usually seen in patients with lung primaries or liver metastases from bowel primary carcinoid tumour that escape the enterohepatic circulation and enter directly into the systemic blood supply.

Otherwise, if the mediators are released from a primary bowel carcinoid tumour, they are released into portal venous blood supply and are metabolized by the liver.

REFERENCES

  1. The MD Anderson Manual of Medical Oncology, 3e. Chapter 26: Neuroendocrine Tumors. Daniel M. Halperin; James C. Yao
Get Medical Pearls directly to your inbox every week!
Weekly posts with high yield medical knowledge, directly to your mailbox!
Dr. C Humphreys

Internal Medicine

Share
Published by
Dr. C Humphreys

Recent Posts

Nocturia and OSA: Mechanism

Nocturia is a common symptom associated with obstructive sleep apnea. [1] Img Cred: Am J…

8 months ago

ASD vs. VSD Murmur Difference

ASD (Atrial Septal Defect) Wide, Fixed split S2 (in contrast to the normal variation in…

8 months ago

Mechanism of a Mixed Apnea

Mixed apneas are characterized by absent respiratory effort and airflow in the first section of…

2 years ago

How Does Hypothyroidism Cause Hypoventilation?

Although rare, the differential diagnosis of hypoventilation and hypercapnia respiratory failure includes hypothyroidism. It is…

2 years ago

Why is Pro-BNP/ BNP lower in Obesity?

B-type natriuretic peptide (BNP) is a hormone created in response to cardiac wall stretch due…

2 years ago

What is Peribronchovascular Distribution on CT imaging?

A common finding described on computed tomography (CT) imaging. A disease with a peribronchovascular distribution…

3 years ago

This website uses cookies.