30 year old female with HIV/AIDS, a recent CD4 count of 7 who presented with 4 weeks of diarrhea, nausea, vomiting and odynophagia. She reported weight loss of 190 lbs over the last 6 months. She had been recently admitted with similar complaints and diagnosed with Cryptosporidial diarrhea and esophageal candidiasis. She was readmitted and started on therapy for Cryptosporidium. Neurological exam and MRI were unremarkable on day 2. On day 12, the patient became disoriented to time, and was unable to remember her children’s ages. She had no gait abnormality or nystagmus, and blood glucose levels were normal. Lumbar puncture was performed, and ruled out infection. A repeat MRI showed hyperintensity of the mamillary bodies and of the medial thalamus bilaterally, suggestive of thiamine deficiency (beriberi). The patient was started on IV thiamine, and had resolution of symptoms over the next 2 days.
Discussion:
Wernicke encephalopathy (WE) is commonly seen in patients with heavy alcohol use and can be seen in up to 59% of alcoholic patients. It can also be seen in patients with malnutrition from other causes including anorexia, gastrointestinal surgery (especially bariatric surgery), malignancy and AIDS. The body stores about 30-50mg of thiamine, and these stores can be depleted within 4-6 weeks without dietary intake. It is an important cofactor for enzymes that take part in energy metabolism including the citric acid cycle, and its deficiency inhibits the production of multiple neurotransmitters. Time to development of WE is variable and early symptoms include nausea, vomiting, fatigue and weakness. The classic triad of ataxia, memory loss and nystagmus is a later manifestation and is seen in about 10% of cases. Treatment is with thiamine supplementation, which is relatively inexpensive and has no significant side effects. Initiation of therapy should begin as soon as there is clinical suspicion as it can progress rapidly to Korsakoff dementia, coma and death. Clinical improvement is evident within hours, however complete resolution of symptoms can take days. In our patient, the presence of AIDS led to a more extensive malignant and infectious work up, with thiamine being initiated only after suggestive radiographic findings. This delay in therapy highlights the fact that thiamine deficiency is an easily overlooked cause of altered mental status.
Conclusions:
Thiamine deficiency leading to WE is a diagnosis that is often missed due to a lack of suspicion in nonalcoholic patients, especially when the classic triad of symptoms is not present. It should be recognized that most patients with beriberi lack one or more elements of the classic triad. In patients with altered mental status and risk factors for nutritional deficiency, thiamine deficiency should be considered and supplementation initiated as it is an easily reversible cause of altered mental status with significant morbidity associated with misdiagnosis and inadequate treatment. This case is also a good example of clinician’s diagnostic reasoning being swayed by other coexisting medical conditions.