Niacin deficiency: Difference between revisions

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** Complication of bariatric surgery
** Complication of bariatric surgery
** Anorexia nervosa
** Anorexia nervosa
** Malabsorption
** Malasorption
* Can also be seen in [[carcinoid syndrome]], prolonged use of [[isoniazid]], and [[Hartnup disease]]
* Can also be seen in [[carcinoid syndrome]], prolonged use of [[isoniazid]], and [[Hartnup disease]]



Latest revision as of 16:10, 14 July 2024

Background

  • Deficiency in the water-soluble vitamin B3
  • Also known as pellagra
  • Risk factors include:
    • Resource-limited countries were diet is heavy in untreated corn or sorghum (India, parts of China, and Africa; in Mexico, corn is treated and pellagra is rare)
    • Alcohol use disorder
    • Complication of bariatric surgery
    • Anorexia nervosa
    • Malabsorption
  • Can also be seen in carcinoid syndrome, prolonged use of isoniazid, and Hartnup disease

Clinical Manifestations

  • Classic triad of photosensitive pigmented dermatitis, diarrhea, and dementia
  • Causes symmetric hyperpigmented rash that looks like a sunburn, on sunexposed skin ("Casal necklace")
  • Also: red tongue, diarrhea, vomiting, insomnia, anxiety, disorientation, delusions, dementia, and encephalopathy

Investigations

  • Urinary N-methylnicotinamide or erythrocyte NAD:NADP ratio
    • Not readily available