Carcinoid syndrome & Niacin deficiency:

Carcinoid syndrome is associated with Niacin deficiency because of increase conversion of tryptophan to serotonin.


Pellagra (niacin deficiency) is most commonly a disorder among people eating corn-based diets but can also be seen in alcoholics.

Tryptophan is converted to niacin with an efficiency of 60:1 by weight. Therefore, in a patient with congenital defects in tryptophan absorption or with increased conversion of tryptophan to serotonin, niacin deficiency can develop.

The early symptoms of pellagra include anorexia,irritability, abdominal pain and vomiting, and glossitis. Vaginitis and esophagitis may also occur.

The four Ds of pellagra are dermatitis, diarrhea, and dementia leading to death.


Expected Clinical Vignette:


Doing rounds in the oncology center, you are see a patient with carcinoid syndrome. Due to the increased conversion of tryptophan to serotonin, this patient has developed niacin deficiency.What symptom you would not expect In this patient?

A. dermatitis
B. dementia
C. diarrhea
D. dyslipidemia
E. glossitis

ANS: (D)

Dyslipidemia is not a part of the pellagra syndrome.

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