Confusion + ataxia
Thiamine (B1) deficiency
TriadConfusion + ophthalmoplegia + gait ataxia (full triad ~10–16%)
MRIMamillary bodies, periaqueductal gray, medial thalami
TreatmentThiamine 500 mg IV TID ×2–3 d → 250 mg daily
UntreatedKorsakoff (irreversible amnesia)
The full Wernicke triad shows up in only ~10–16% — one feature in a malnourished patient means treat now.
Key clinical features
- Confusion / global encephalopathy
- Ophthalmoplegia — nystagmus most common; CN VI palsy, conjugate gaze palsy
- Gait ataxia
- MRI: mamillary bodies, periaqueductal gray, medial thalami
- Full triad only ~10–16% — treat empirically on a single feature
- Causes: alcoholism, bariatric surgery, hyperemesis, refeeding, TPN
◆ Signature clue
Ophthalmoplegia / nystagmus + ataxia + confusion in an alcoholic, bariatric or hyperemesis patient → Wernicke. Untreated → Korsakoff amnesia + confabulation (only ~20% recover).
Diagnosis
Clinical — treat before confirmation. MRI: T2/FLAIR + diffusion restriction in mamillary bodies, periaqueductal gray, medial thalami. ↑ RBC transketolase supports it.
Management
Thiamine 500 mg IV TID ×2–3 d, then 250 mg daily. Give thiamine before or with glucose when possible; never delay emergent dextrose for hypoglycemia.