Neurologic Complications of Alcohol and B12 Deficiency

Abstract

This chapter reviews the major neurologic complications from alcohol intoxication and withdrawal plus vitamin B₁₂ deficiency syndromes. Alcoholism, the addiction to alcohol, is characterized by a craving for alcohol and a tolerance to its intoxicating effects. Worldwide, alcoholism has an enormous societal impact and is the number one abused drug in the world. The metabolism and rapid distribution of ethanol is described. Complications of alcoholism involve many organs but damage to the central nervous system and peripheral nervous system is particularly common. Specific alcohol syndromes are described, including drunkenness and alcoholic coma, alcohol withdrawal syndromes, alcohol withdrawal seizures, delirium tremens, Wernicke’s encephalopathy and Korsakoff’s syndrome, alcoholic cerebellar degeneration, alcoholic polyneuropathy, and fetal alcohol syndrome. Attention is given to their pathophysiology, major clinical features, major laboratory findings, and principles of management and prognosis. The chapter then switches to vitamin B₁₂ (cyanocobalamin) deficiency, or subacute combined degeneration. Again its pathophysiology, major clinical features, major laboratory findings, and principles of management and prognosis are discussed.

A 48-year-old man who has a history of alcohol abuse and hypertension is brought in by ambulance to the emergency room after having a seizure witnessed by his roommate. On exam, the patient is confused and agitated but there is no seizure activity. After 30 min, the patient becomes less confused but remains tremulous. His blood alcohol level is zero. Neuroimaging was normal. After the patient is more cooperative, he reports that his last drink of alcohol was 2 days ago in an attempt to go “cold turkey”. The neurologist diagnoses him with an alcohol withdrawal seizure.