Causes of Wernicke's Encephalopathy
Wernicke's encephalopathy is primarily caused by thiamine (vitamin B1) deficiency, which can result from various clinical conditions that lead to malnutrition or impaired thiamine absorption. 1, 2
Primary Causes
- Alcoholism: The most common cause of Wernicke's encephalopathy in the United States 2
- Bariatric surgery: Particularly vertical banded gastroplasty and other gastric partitioning procedures that can lead to persistent vomiting and malnutrition 3, 1
- Persistent vomiting: From various causes including hyperemesis gravidarum, drug-induced conditions, and gastrointestinal illnesses 1, 4
- Malabsorption conditions: Including those resulting from gastrointestinal diseases or surgeries 2, 5
- Prolonged intravenous feeding: Particularly without proper thiamine supplementation 3, 5
Additional Risk Factors
- Gastric carcinoma and pyloric obstruction: Leading to reduced food intake or malabsorption 3, 1
- Hyperemesis gravidarum: Severe nausea and vomiting during pregnancy 3, 1
- Malnutrition: From any cause including starvation, eating disorders, or chronic illness 1, 6
- Parenteral nutrition without thiamine: A significant risk when multivitamin infusion is not included 5
Pathophysiology
Thiamine deficiency leads to characteristic neurological sequelae including:
- Mental status changes (confusion, disorientation) 1, 2
- Ocular abnormalities (nystagmus, ophthalmoplegia, conjugate gaze palsy) 3, 1
- Ataxia and incoordination 1, 7
Clinical Presentation
The classic triad of Wernicke's encephalopathy includes:
- Mental status changes: Confusion, disorientation, and altered consciousness 1, 2
- Ocular findings: Nystagmus, ophthalmoplegia, and conjugate gaze palsy 3, 1
- Ataxia: Unsteady gait and incoordination 1, 7
However, it's important to note that the complete triad is present in only about 10% of cases, making diagnosis challenging 2.
Special Considerations
- Non-alcoholic Wernicke's encephalopathy may present atypically and is often missed or diagnosed late 7
- Post-bariatric surgery patients are at particularly high risk due to reduced food intake, malabsorption, and frequent vomiting 1, 6
- Patients receiving glucose solutions without thiamine supplementation are at risk of precipitating or worsening Wernicke's encephalopathy 8, 9
Prevention
- Early thiamine supplementation in at-risk patients 1, 6
- Nutritional supplementation after bariatric surgery 3
- Administration of thiamine before any glucose-containing solutions in at-risk patients 6, 9
Common Pitfalls
- Failure to recognize Wernicke's encephalopathy in non-alcoholic patients 7
- Administering glucose-containing solutions before thiamine in at-risk patients 6, 9
- Relying on oral thiamine in acute cases when absorption may be compromised 6
- Waiting for the complete classic triad to appear before initiating treatment 2