Suspected dietary-related Wernicke’s encephalopathy

Abstract

A 64-year-old female presented with fluctuating level of consciousness of unclear cause. She had radiological features of right middle lobe consolidation and raised inflammatory markers, but normal computed tomography scan of head and normal cerebrospinal fluid results. She was intubated and ventilated with nasogastric feeding for four days and had fully recovered after six days. Upon recovery, the patient disclosed that she had maintained an ice cream-only diet for three years prior to this presentation. She was therefore diagnosed with Wernicke’s encephalopathy secondary to dietary insufficiency of thiamine, which was acutely precipitated by pneumonia and recovered following establishment of appropriate nutrition.

Case presentation

A 64-year-old female was brought in by ambulance having been found unresponsive at home by family members. Her collateral history revealed that she had a laparoscopic cholecystectomy three years prior, previous alcohol abuse with 10 years abstinence and chronic back pain for which she took zomorph, temazepam, gabapentin and a fentanyl patch. There was no evidence of any drug overdose.

Her Glasgow Coma Scale (GCS) levels fluctuated between 3 and 15 out of 15. She was hypotensive and tachycardia (BP: 81/47, heart rate: 115). In A+E resus, the patient was initially able to communicate, but within an hour of admission, she became progressively agitated. Critical care review was requested, at which point the patient’s GCS continued to fluctuate despite receiving naloxone. Rapid sequence induction and intubation was carried out to facilitate a computed tomography (CT) brain.

Blood testing showed a neutrophilia with white cell count 23.8, C-reactive protein 9.0, creatinine of 170 from a baseline of 80, otherwise unremarkable full blood count, electrolytes and liver function tests. An arterial blood gas demonstrated a metabolic acidosis with a pH of 7.313, lactate of 4.77.

CT head showed focal hypoattenuation within the genu of the right internal capsule consistent with a lacunar infarct of indeterminate age. A chest X-ray showed right middle lobe consolidation.

The patient was initially fluid resuscitated and treated with ceftriaxone and acyclovir to cover for meningoencephalitis. A lumbar puncture undertaken on admission showed raised cerebrospinal fluid lactate (5.7) and protein (0.58); with normal glucose, no lymphocytes and negative for routine viral polymerase chain reaction (PCR). Following this, ceftriaxone was changed to tazocin to treat her right middle lobe pneumonia and acyclovir was continued.

She remained intubated for four days due to agitation and not obeying commands. Following extubation, she remained intermittently agitated with fluctuating GCS between 12 and 14. A repeat lumbar puncture on day 5 of admission was unremarkable and once again tested negative for viral PCR. Blood cultures and respiratory cultures did not show any infective organisms.

On day 6 of admission, the patient fully recovered and was alert and orientated with no focal neurological deficit. At this point, a detailed history revealed that since her laparoscopic cholecystectomy three years prior she had maintained a diet consisting nearly entirely of ice cream. She would occasionally eat apples or bananas and sweets, and drank fruit flavoured sparkling water. She told us that prior to her surgery she had been advised to eat a zero fat diet, and postoperatively she had started eating exclusively ice cream as she had craved it during her abstinence from fat, and found it comfortable to eat.

Upon further questioning, the patient admitted to intermittent forgetfulness prior to admission. She would put objects in the wrong place around the house, for example knives down the back of sofa.

A neurology review was requested at which point she was diagnosed as having had Wernicke’s encephalopathy due to thiamine deficiency, acutely precipitated by a community-acquired pneumonia. This resolved as a result of five days of nasogastric feeding.

A magnetic resonance imaging (MRI) brain was considered to confirm the diagnosis, but as the patient had fully recovered, it would not have changed our management and was therefore deemed unnecessary.

The patient was reviewed by a dietician who gave her advice on how to maintain a more balanced diet. She was motivated to change her dietary habits and was eating normal meals on the ward prior to discharge.

Discussion

Wernicke’s encephalopathy is a condition resulting from thiamine deficiency, classically as a triad of opthalmoplegia, gait ataxia and altered mental state. ¹ Over 80% of cases in developed countries are associated with alcohol abuse. ² Other common causes include malignant disease, gastrointestinal disease and surgery, and hyperemesis gravidarum. ³

Depleted intracellular thiamine is thought to lead to a cellular energy deficit which, whilst initially reversible, will ultimately lead to cell death. ⁴ Untreated, the condition will result in permanent brain damage featuring loss of short-term memory, termed Korsakoff’s psychosis. ⁴

Acute Wernicke’s may be precipitated by systemic infection. ⁵ Despite the common clinical description, retrospective analysis of autopsy-confirmed cases has found that only 16% had the classic triad and 19% had no documented clinical signs. ¹ It is therefore important to identify at-risk patients in order to make the diagnosis.

It is a clinical diagnosis which can be supported by MRI findings of ‘symmetrical alterations in the thalami, mamillary bodies, tectal plate and periaqueductal area’. ⁶ CT has comparatively low sensitivity in the acute phase. The European Federation for Neurological Sciences recommends that a diagnosis of Wernicke’s encephalopathy be made when two of the following signs are present: (i) dietary deficiencies, (ii) eye signs, (iii) cerebellar dysfunction and (iv) either an altered mental state or a mild memory impairment. ³

Treatment is with high-dose parenteral thiamine until symptoms resolve, prior to administration of carbohydrates which may otherwise precipitate Wernicke’s encephalopathy. ³

Daily requirements of thiamine are between 1 and 2 mg per day, and normal body stores may be depleted within four to six weeks if a thiamine-free diet is maintained. ⁴ Typical commercially available ice cream in the United Kingdom has between 0.04 and 0.1 mg per 100 g, meaning between 1 and 5 kg of ice cream per day is needed to maintain body stores. ⁷ Hutcheon describes a case of Wernicke’s encephalopathy secondary to a 40-day water-based fasting diet. ⁸

Conclusion

This case report was written as it presents an unusual aetiology of an under-diagnosed cause of neurological impairment. Patients admitted to hospital with reduced levels of consciousness or confusion are not able to provide a history, presenting a diagnostic challenge to their medical team. It is therefore important to be aware of a wide differential of causes for these symptoms, given that the potentially fatal Wernicke’s encephalopathy can be easily treated.

Learning points

Wernicke’s encephalopathy should be included in the differential diagnosis of patients presenting with neurological impairment.

Treatment with intravenous thiamine is safe and effective. There should be a low threshold for administration in patients presenting with a reduced GCS of uncertain aetiology.

The classically described triad of ophthalmoplegia, gait ataxia and altered mental state occur together in a minority of cases.

Wernicke’s encephalopathy does not only occur in patients who consume excessive alcohol.

A thorough history should include dietary and nutritional status of a patient.

Consent

Written consent for publication has been obtained from the patient.