Wernicke Encephalopathy

Wernicke encephalopathy is a frequently underdiagnosed serious condition caused by thiamine (vitamin B 1) deficiency. In the developed world, thiamine deficiency is mostly associated with reduced thiamine uptake due to chronic alcohol abuse and malnutrition. 

The condition can also arise in non-alcoholic patients as a consequence of prolonged starvation, bariatric surgery, severe nausea and vomiting during pregnancy, feeding with mainly glucose, or congenital transketolase function abnormalities. 

In the general population, the incidence of Wernicke encephalopathy was determined to lie between 0.8% and 2.8%, whereas in a population of alcoholics, the incidence can reach 12.5%.

Signs and Symptoms

Classical symptoms of Wernicke encephalopathy include changes of mental status, gait ataxia and ocular motor dysfunction such as upbeat nystagmus, convergence retraction nystagmus, impairment of horizontal or vertical saccades. In addition patients may also suffer of hypotension, hypothermia and somnolence.

Diagnosis

Diagnosing Wernicke encephalopathy is not always easy, since in up to 90% of patients, it may not present with the classical symptoms. 

The observation of any of the two following conditions is sufficient to reach a presumptive diagnosis: ocular motor disorders, ataxia, mental status change, nutritional deficiency. In the case of Wernicke encephalopathy, overdiagnosis is preferred to underdiagnosis, since timely intervention is necessary with misdiagnosis potentially leading to grave consequences. Therefore, if the diagnosis is suspected patients should be immediately treated.

In addition, MRI is a good way to reach a definitive diagnosis, even though the reported sensitivity is only 53% for active disease.

Observable ocular motor disorders

  • Convergence-retraction nystagmus
  • Impairment of horizontal saccades
  • Impairment of vertical saccades
  • Upbeat nystagmus

References

Thomson AD, et al. The royal college of physicians report on alcohol: Guidelines for managin Wernicke’s encephalopathy in the accident and emergency department. Alcohol and Alcoholism, 2002, 37(6):513-521.PubMed

Donnino MW, et al. Myths and Misconceptions of Wernicke’s Encephalopathy: What Every Emergency Physician Should Know. Annals of Emergency Medicine, 2007, 50(6):715-721.PubMed