Beyond the “Classic” Triad: Diagnosing and Managing Wernicke Encephalopathy
A 65 year old man is brought in by EMS after a fall in the setting of alcohol intoxication. He has a history of alcohol use disorder, COPD, and hypertension. He does not remember the events leading up to the fall, but he does recall having some beers with his friend and buying vodka from the liquor store below his apartment. He reports a 17-year history of daily alcohol consumption of a pint of vodka, and a limited diet. On exam, he has horizontal nystagmus on left and right gaze, and vertical nystagmus on upward and downward gaze. He is alert and oriented to self and place, and becomes oriented x3 over the course of several hours. His gait is normal, and his exam is otherwise unremarkable. His head and C-spine CT scans are clear. He is admitted to Neurology out of concern for Wernicke encephalopathy given his nystagmus. He is given thiamine and vitamin B12, the nystagmus resolves completely, and he is discharged.
In medical school we’re taught many “classic” disease presentations. We’re also taught that patients don’t read the textbook, and this case reminds us of this reality of practicing medicine. Wernicke encephalopathy classically presents with a triad of ophthalmoplegia, ataxia, and confusion. However, this patient presented with isolated nystagmus, which raises an important clinical question for Emergency Medicine physicians.
What are the necessary criteria to diagnose Wernicke encephalopathy?
Summary of Evidence
Wernicke encephalopathy (WE) and Wernicke-Korsakoff syndrome (WKS) are potentially life-threatening neurologic conditions caused by thiamine deficiency. Patients at risk of WE and WKS include not only those with chronic alcohol consumption, but all at risk of nutritional deficiency. This includes patients with eating disorders, bariatric surgery, hyperemesis gravidarum, and hypermetabolic states such as malignancy. (1,2)
Autopsy studies estimate the prevalence of WE and WKS at 0.4 – 2.8%. (3)
WE remains underdiagnosed. A recent study estimated that providers do not consider WE in as many as 68% of patients with chronic alcohol use and 94% of patients without chronic alcohol use. (4)
Presentations of WE vary widely. As few as 10% of cases present with the complete triad. 19% of patients have no signs. Ocular findings are variable and include nystagmus, cranial nerve VI palsy, and conjugate gaze palsy. The most common sign is a mental status change. (5)
The Caine Criteria are a validated set of criteria that can be used to make the diagnosis of WE with a sensitivity of 85% and a specificity of 100%. The Caine Criteria state that two of the following four signs are required to clinically diagnose WE:
Altered mental status OR mild memory impairment. (3)
Of note, the Caine criteria were validated in a group of 106 patients with chronic alcohol use, and they have not been validated in patients without alcohol consumption. However, several professional societies recommend their use in all patients with clinical conditions that could result in thiamine deficiency. (3)
Once the diagnosis of WE is made, treatment is focused on repletion by giving 500mg of IV thiamine TID for at least three days. Correction of hypomagnesemia is also important, as it may cause resistance to thiamine repletion. Finally, correction of vitamin B12 and other deficiencies is also necessary. (6)
Rapid correction of the initial presenting signs indicates sufficient treatment. However, some patients may experience persistent neurologic dysfunction. Patients at continued risk of WE should be given a prophylactic dose of 100mg PO q daily. (6)
WE remains underdiagnosed.
Consider WE in patients at risk of nutritional deficiency, including those with chronic alcohol use, eating disorders, bariatric surgery, hyperemesis gravidarum, and hypermetabolic states.
Use the Caine Criteria to diagnose WE. 2 of the 4 signs are required for diagnosis.
Treat patients with 500mg thiamine IV TID for at least three days. Patients at continued risk of WE should receive 100mg PO daily.
Disposition: admit for thiamine repletion
C. Sharp, M. Wilson, K. Nordstrom. Psychiatric Emergencies for Clinicians: Emergency Department Management of Wernicke-Korsakoff Syndrome. J Emerg Med, 51 (2016).
J. Wu, L. Zhang, Az. Vaze, S. Lin, J. Juhaeri. Risk of Wernicke’s encephalopathy and cardiac disorders in patients with myeloproliferative neoplasm. Cancer Epidemiol, 39 (2015).
R. Galvin, G. Brathen, A. Ivashynka, et al. EFNS guidelines for diagnosis, therapy and prevention of Wernicke encephalopathy. Eur J Neurol, 17 (2010).
G.S. Day, C.M. del Campo. Wernicke encephalopathy: a medical emergency. CMAJ, 186 (2014).
M.W. Donnino, J. Vega, J. Miller, M. Walsh. Myths and misconceptions of Wernicke’s encephalopathy: what every emergency physician should know. Ann Emerg Med, 50 (2007).
A.D. Thomson, C. Cook, R. Touquet, J. Henry. The royal college of physicians report on alcohol: guidelines for managing Wernicke’s
encephalopathy in the accident and emergency department. Alcohol Alcohol, 37 (2002).