Which clinical feature best distinguishes thiamine (vitamin B1) deficiency from riboflavin (vitamin B2) deficiency?

Explanation

## Distinguishing Thiamine from Riboflavin Deficiency ### Clinical Features Comparison | Feature | Thiamine (B1) Deficiency | Riboflavin (B2) Deficiency | |---------|--------------------------|---------------------------| | **Neurological** | Wernicke encephalopathy, Korsakoff syndrome, peripheral neuropathy (beriberi) | Minimal neurological involvement | | **Mucosal** | Minimal oral changes | Cheilosis, angular stomatitis, glossitis | | **Dermatological** | Dermatitis (rare) | Seborrheic dermatitis, photophobia | | **Ocular** | Minimal | Corneal vascularization, photophobia | | **Cardiac** | High-output heart failure (wet beriberi) | Not typical | **Key Point:** Thiamine deficiency is uniquely characterized by **Wernicke encephalopathy** (confusion, ophthalmoplegia, ataxia) and **peripheral neuropathy**, which are pathognomonic and absent in riboflavin deficiency. **High-Yield:** The triad of Wernicke encephalopathy — confusion, ophthalmoplegia, ataxia — is virtually diagnostic of acute thiamine deficiency and does NOT occur in B2 deficiency. **Clinical Pearl:** Riboflavin deficiency presents with **mucosal and ocular** manifestations (cheilosis, angular stomatitis, corneal vascularization), while thiamine deficiency presents with **neurological** manifestations (Wernicke, Korsakoff, beriberi neuropathy). **Mnemonic:** **WERNICKE = Thiamine** (W = Wernicke, E = Encephalopathy, R = Reflex loss, N = Neuropathy, I = Impaired memory, C = Confusion, K = Korsakoff, E = Eye signs). **RIBOFLAVIN = Mucosal** (R = Redness at angles of mouth, I = Inflammation, B = Burning sensation, O = Ocular vascularization, F = Fissures at lips, L = Lips affected, A = Angular stomatitis, V = Vascularization, I = Inflammation, N = Nails affected).