Neurology · Nutritional Neurological Disorders
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Wernicke encephalopathy is caused by a thiamine (vitamin B1) deficiency typically seen in patients with chronic alcohol use disorder, malnutrition, or hyperemesis gravidarum.
The classic clinical triad consists of encephalopathy, oculomotor dysfunction (e.g., nystagmus, ophthalmoplegia), and gait ataxia.
Administer intravenous thiamine immediately upon clinical suspicion, before the administration of glucose-containing fluids, to prevent the precipitation of acute symptoms.
Failure to treat Wernicke encephalopathy promptly can lead to Korsakoff syndrome, characterized by irreversible anterograde and retrograde amnesia and confabulation.
The diagnosis is primarily clinical, but MRI of the brain may reveal hyperintense T2/FLAIR signals in the medial thalami, mammillary bodies, and periaqueductal gray matter.
Oculomotor findings often present as bilateral abducens nerve palsy or horizontal nystagmus due to involvement of the abducens nuclei and vestibular nuclei.
Wernicke encephalopathy is a medical emergency that requires high-dose parenteral thiamine replacement to prevent permanent neurological sequelae.
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A 48-year-old male with a history of chronic alcohol use disorder is brought to the emergency department by his sister due to confusion. On physical examination, the patient appears disheveled and malnourished. He exhibits bilateral horizontal nystagmus, gait ataxia, and disorientation to time and place. His sister reports he has not eaten a solid meal in several days. The patient is currently hemodynamically stable.
What is the most appropriate next step in management?
Intravenous thiamine administration
The patient presents with the classic triad of Wernicke encephalopathy; immediate parenteral thiamine is required before any glucose administration to prevent worsening of the condition.
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Etiology / Epidemiology
Primarily affects chronic alcoholics and patients with malnutrition (hyperemesis gravidarum, gastric bypass).
Clinical Manifestations
Classic triad: Ophthalmoplegia, Ataxia, and Confusion.
Diagnosis
Clinical diagnosis; MRI brain (T2/FLAIR) shows hyperintensity in mammillary bodies.
Treatment
Immediate IV Thiamine (Vitamin B1) before glucose administration.
Prognosis
Untreated leads to Korsakoff syndrome; mortality up to ~20%.
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Epidemiology & Etiology
Occurs due to severe thiamine deficiency impairing aerobic metabolism. High-risk groups include chronic alcohol use disorder, patients with anorexia nervosa, and those post-bariatric surgery. Always consider in patients with unexplained altered mental status.
Pertinent Anatomy
Lesions typically localize to the thalamus and mammillary bodies. Involvement of the periaqueductal gray and vestibular nuclei explains the classic ocular and gait findings.
Pathophysiology
Thiamine is a necessary cofactor for transketolase and pyruvate dehydrogenase. Deficiency leads to impaired ATP production and localized neuronal cell death. Glucose administration without thiamine exacerbates the deficit, potentially triggering acute metabolic collapse.
Clinical Manifestations
The classic triad is present in only 16-38% of cases; look for nystagmus and gaze palsies. Confusion is the most common symptom. If left untreated, patients develop the irreversible Korsakoff syndrome, characterized by confabulation and profound anterograde amnesia.
Diagnosis
Diagnosis is strictly clinical. MRI brain is the gold standard imaging, revealing symmetric hyperintensities in the medial thalamus and mammillary bodies. Serum thiamine levels are often unreliable and should not delay emergent treatment.
Treatment
Administer IV Thiamine (typically 500mg TID) immediately. Never give glucose before thiamine as it can precipitate or worsen the condition. Follow with magnesium supplementation if levels are low, as hypomagnesemia prevents thiamine utilization.
Prognosis
Ocular symptoms often resolve within hours of treatment. Ataxia and confusion may improve, but Korsakoff syndrome (permanent memory deficit) is a common, irreversible complication if treatment is delayed.
Differential Diagnosis
Korsakoff syndrome: Presence of confabulation and chronic memory loss
Hepatic encephalopathy: Presence of asterixis and elevated ammonia
Delirium tremens: Presence of autonomic hyperactivity and tremors
Hypoglycemia: Rapid reversal with glucose administration
Vitamin B12 deficiency: Presence of subacute combined degeneration and macrocytic anemia