Triad of Carcinoid syndrome
Triad of Carcinoid syndrome
The classic triad of carcinoid syndrome is:
- Flushing – episodic cutaneous vasodilation, often of the face and upper chest.
- Diarrhea – secretory, watery diarrhea due to serotonin and other mediators.
- Right-sided valvular heart disease (carcinoid heart disease) – particularly tricuspid regurgitation and pulmonary stenosis, caused by serotonin-induced fibrous deposits on valves.
📌 Sometimes bronchospasm (wheezing/asthma-like attacks) is also included, making it a tetrad in many references.
Q1. The classic triad of Carcinoid syndrome includes:
The classic triad is flushing, diarrhea, and right-sided valvular lesions.
Q2. The principal mediator responsible for Carcinoid syndrome is:
Serotonin excess is the key cause of diarrhea and valvulopathy.
Q3. Carcinoid syndrome usually manifests after metastasis to the:
Liver metastasis allows serotonin to bypass first-pass metabolism and enter systemic circulation.
Q4. The most commonly affected valve in Carcinoid heart disease is:
The tricuspid valve is most commonly affected, leading to regurgitation.
Q5. The diagnostic urinary marker for Carcinoid syndrome is:
5-HIAA in 24h urine is the key biochemical test.
Q6. The most common primary site of Carcinoid tumors is:
The ileum is the most frequent primary site of Carcinoid tumors.
Q7. Niacin deficiency in Carcinoid syndrome occurs due to diversion of tryptophan into:
Tryptophan is shunted to serotonin synthesis, depleting niacin.
Q8. Pellagra in Carcinoid syndrome presents with:
Pellagra is defined as diarrhea, dermatitis, and dementia.
Q9. The most sensitive imaging for Carcinoid tumors is:
Somatostatin receptor scintigraphy (Octreoscan) is highly sensitive.
Q10. First-line drug for symptom control in Carcinoid syndrome is:
Octreotide and Lanreotide are first-line drugs.
Q11. Which of the following is a precipitant of Carcinoid crisis?
Surgery, anesthesia, and stress can trigger massive mediator release.
Q12. In Carcinoid heart disease, endocardial plaques are typically composed of:
Endocardial plaques are fibrous in nature due to serotonin-induced fibrosis.
Q13. Bronchospasm in Carcinoid syndrome is due to:
Mediators like serotonin, histamine, and bradykinin cause bronchospasm.
Q14. Which vitamin deficiency is common in Carcinoid syndrome?
Niacin deficiency results from tryptophan diversion to serotonin.
Q15. The flushing in Carcinoid syndrome is usually:
Flushing is episodic due to mediator release and cutaneous vasodilation.
Q16. Carcinoid tumors are best histologically characterized by:
Carcinoid tumors are neuroendocrine and stain for chromogranin, synaptophysin.
Q17. Which of the following is used for intraoperative prophylaxis against Carcinoid crisis?
IV Octreotide is administered perioperatively to prevent Carcinoid crisis.
Q18. The diarrhea in Carcinoid syndrome is best described as:
Carcinoid diarrhea is typically watery and secretory due to serotonin.
Q19. Which cardiac lesion is LEAST likely in Carcinoid syndrome?
Left-sided lesions (like aortic regurgitation) are rare due to serotonin inactivation in lungs.
Q20. Which therapy offers definitive cure for localized Carcinoid tumor?
Surgical removal is the definitive curative treatment for localized Carcinoid tumors.
| No. | Key Point |
|---|---|
| 1 | Classic triad: flushing, diarrhea, right-sided valvular disease |
| 2 | Caused by neuroendocrine tumors secreting serotonin and other mediators |
| 3 | Most common primary site: small intestine (ileum) |
| 4 | Carcinoid syndrome usually occurs after liver metastasis |
| 5 | Main mediator: serotonin (5-HT) |
| 6 | Other mediators: bradykinin, histamine, prostaglandins |
| 7 | Urinary marker: 5-HIAA (24-hour urine) |
| 8 | Most sensitive imaging: somatostatin receptor scintigraphy (Octreoscan) |
| 9 | First-line drug therapy: somatostatin analogs (Octreotide, Lanreotide) |
| 10 | Pellagra (dermatitis, diarrhea, dementia) occurs due to niacin deficiency |
| 11 | Niacin deficiency from tryptophan diversion to serotonin synthesis |
| 12 | Most common cardiac lesion: tricuspid regurgitation |
| 13 | Pulmonary stenosis is also frequent in Carcinoid heart disease |
| 14 | Left-sided lesions rare due to serotonin inactivation in lungs |
| 15 | Endocardial plaques consist of fibrous tissue |
| 16 | Carcinoid crisis may occur during surgery/anesthesia |
| 17 | Carcinoid crisis prevented with IV Octreotide infusion |
| 18 | Histology: neuroendocrine cells positive for chromogranin, synaptophysin |
| 19 | Diarrhea is typically watery and secretory |
| 20 | Definitive treatment: surgical resection of localized tumor |
