21B. Neurological disorders related to alcoholism

Wernicke encephalopathy

Wernicke encephalopathy is an acute and reversible consequence of thiamine deficiency which usually occurs due to alcoholism. The lesion is in the brainstem.

It presents with the triad of confusion, oculomotor dysfunction (nystagmus, ptosis, diplopia, gaze palsy), and gait ataxia. The diagnosis is based on patient history and clinical features.

It’s a medical emergency which must be treated with IV thiamine rapidly to prevent progression to Korsakoff syndrome, followed up by long term thiamine supplementation to prevent recurrence. However, many retain some of the symptoms despite early treatment. Administration of glucose depletes thiamine, so additional thiamine must be supplemented in case of glucose administration.

Korsakoff syndrome

Korsakoff syndrome is a chronic and irreversible consequence of alcoholism, usually due to long-term thiamine deficiency. It’s a psychiatric syndrome which presents with short-term memory loss, disorientation, and confabulation. The patient should receive thiamine supplementation to prevent progression, but there is no way to improve the symptoms which have already developed.

Alcoholic polyneuropathy

Alcoholism is the second most common cause of polyneuropathy. These patients have typical symptoms of polyneuropathy, i.e. symmetric, distal numbness, paraesthesia, pain, loss of reflexes, etc.

Other disorders

• Alcoholic cerebellar degeneration – cerebellar symptoms
• Alcoholic myopathy – muscle weakness
• Alcoholic myelopathy
• Delirium tremens – agitation, tremor, hallucination, autonomic hyperactivity
• Provoked seizures
• Rhabdomyolysis
• Marchifava-Bignami disease – demyelination and necrosis in corpus callosum, focal neurological deficits, altered mental status, dysarthria