Wernicke Encephalopathy (WE) is an acute, reversible neurological emergency caused by thiamine (vitamin B1) deficiency, most commonly associated with chronic alcohol use disorder. It classically presents with a triad of symptoms:
✅ Ophthalmoplegia
✅ Ataxia
✅ Global confusion
However, this full triad is seen in only 1/3 of cases.
Etiology & Risk Factors
| Cause | Details |
|---|---|
| Chronic alcoholism | Most common cause; impairs thiamine absorption and storage |
| Malnutrition | Seen in eating disorders, cancer, AIDS |
| Hyperemesis gravidarum | Severe vomiting during pregnancy leading to nutritional deficiencies |
| Prolonged fasting or starvation | Increases risk of thiamine depletion |
| Gastric bypass surgery | Reduced thiamine absorption postoperatively |
| Glucose administration without thiamine | Can precipitate WE in at-risk individuals |
Pathophysiology
Thiamine is a critical coenzyme for enzymes involved in glucose metabolism:
- Transketolase (pentose phosphate pathway)
- Pyruvate dehydrogenase (glycolysis → TCA cycle)
- α-Ketoglutarate dehydrogenase (TCA cycle)
Thiamine deficiency leads to:
- ↓ Cerebral glucose utilization
- ↑ Lactate and glutamate accumulation
- Mitochondrial dysfunction and oxidative stress
- Neuronal excitotoxicity and cell death, particularly in the mammillary bodies, thalamus, hypothalamus, and cerebellum
Clinical Features
Classic Triad (only in ~33%)
- Ophthalmoplegia – Nystagmus, lateral rectus palsy, conjugate gaze palsies, ptosis (rare)
- Gait Ataxia – Wide-based, shuffling gait due to cerebellar and vestibular dysfunction
- Confusion – Global disorientation, apathy, inattentiveness
Other Symptoms
- Nystagmus (horizontal, on lateral gaze)
- Sixth nerve palsy (bilateral lateral rectus weakness)
- Apathy, drowsiness, stupor, or coma in late stages
- Peripheral neuropathy – Burning sensation, decreased reflexes
- Autonomic instability – Hypothermia, postural hypotension, or tremors
🧠 Pupillary responses are usually spared, but may become miotic in advanced cases.
Korsakoff Syndrome (Chronic Phase)
If untreated, WE can progress to Korsakoff Psychosis, a chronic, often irreversible amnestic disorder, characterized by:
- Anterograde and retrograde amnesia
- Confabulation – Fabrication of memories
- Impaired learning and executive function
- Disordered temporal sequencing
🧠 Korsakoff syndrome often follows or coexists with WE and is rarely seen outside alcohol-related thiamine deficiency.
Diagnosis
Clinical diagnosis is critical—do not delay treatment for confirmatory testing.
| Investigations | Notes |
|---|---|
| Thiamine level | Often low, but not required to start treatment |
| MRI Brain | May show hyperintensities in mammillary bodies, thalamus, periaqueductal gray |
| Serum electrolytes | Often show low Mg²⁺, which impairs thiamine utilization |
| Liver function tests | Rule out alcoholic hepatitis |
| Blood glucose | Important to avoid giving glucose before thiamine |
Management
WE is a medical emergency. Treatment must be initiated promptly.
Thiamine Replacement (Before Glucose)
- Thiamine 100 mg IV/IM daily for 5–7 days (can go up to 500 mg/day in severe cases)
- Administer before glucose infusion to prevent worsening of symptoms
- Follow with oral thiamine supplementation once stabilized
Supportive Care
- IV fluids and electrolyte correction
- Treat hypomagnesemia, which impairs thiamine activation
- Nutritional support: high-protein, vitamin-rich diet
- Multivitamin supplementation
- Hospitalization for monitoring in moderate to severe cases
Prognosis & Recovery
| Symptom | Recovery Time |
|---|---|
| Ocular signs | May improve within hours to days after thiamine |
| Ataxia | Improves slowly; often incomplete recovery |
| Confusion/apathy | Gradual improvement over weeks |
| Korsakoff's psychosis | Often irreversible, may lead to long-term disability |
High-Yield NCLEX & USMLE Pearls
- Always give thiamine before glucose in patients at risk (e.g., alcoholics, malnourished)
- Classic triad: confusion + ophthalmoplegia + ataxia
- Wernicke's = acute phase; Korsakoff's = chronic memory disorder
- MRI findings support diagnosis but are not required to start treatment
- Prompt thiamine therapy can prevent permanent brain damage
Nursing Priorities
-
Administer IV thiamine before glucose
-
Monitor mental status, coordination, and ocular movements
-
Educate on alcohol cessation and nutritional support
-
Prevent falls due to ataxia
-
Watch for signs of progression to Korsakoff's syndrome
