American Association of Critical-Care Nurses (AACN) Certification Practice Test

What are the 3 D's of pellagra?

1. Diarrhea, dementia, dermatitis

2. Hypothermia, hypotension, bradycardia

3. CNS depression, respiratory depression, miosis

4. Hypotension, tachycardia, tachypnea

The correct answer is: Diarrhea, dementia, dermatitis

The three D's of pellagra are diarrhea, dementia, and dermatitis. These three symptoms are classic manifestations of niacin (vitamin B3) deficiency, which is the primary cause of pellagra. Diarrhea results from inflammation of the gastrointestinal tract, leading to excessive loss of fluids, nutrients, and electrolytes. This can cause significant dehydration and nutritional deficiencies. Dementia, or cognitive decline, occurs due to the effects of deficiency on the central nervous system. Niacin is vital for brain function, and a lack of it can lead to neurological symptoms that may include confusion, memory loss, and severe mental disturbances. Dermatitis refers to the skin rashes that typically appear on areas of the skin exposed to sunlight. These rashes are often characterized by a "casal's necklace" appearance and can be very painful and itchy, further highlighting the systemic effects of niacin deficiency. In summary, the identification of diarrhea, dementia, and dermatitis as the three D's of pellagra provides critical insights into the consequences of niacin deficiency, reinforcing the importance of proper nutrition for overall health.