Introduction: Over 9000 bariatric surgeries are conducted annually in the UK and post-operative micronutrient deficiency is common. We report a case of dry beriberi secondary to thiamine deficiency following Roux-en-Y bypass surgery.
A 45-year-old Caucasian obese lady (155 kg, BMI 57) presented with progressive proximal limb weakness, upper and lower limb paraesthesia, ataxia and athetoid tremors 18 months following Roux-en-Y gastric bypass surgery. Post-operatively, she lost 57 kg and maintained a healthy diet with moderate alcohol intake (<14 units/week). She admitted non-compliance with multivitamin and Adcal D3 supplementation. Examination revealed grade 3/5 weakness in upper and lower limbs with glove and stocking impaired touch and vibration sensation. Deep tendon reflexes were impaired in lower limbs with preserved extrapyramidal and cerebellar functions. Nerve conduction studies revealed mixed sensory and motor conduction defect. Serum calcium, vitamin B12, magnesium, ferritin, copper, phosphate and vitamin D levels were normal. Initial thiamine status determination was unsuccessful due to unavailability of the test locally. Thiamine deficiency was diagnosed clinically and was commenced on regular parenteral thiamine infusions (100 mg/day) and oral thiamine (300 mg/day). Serum thiamine after two thiamine infusions was 170 nmol/l (66200).
Over the next 24 months, complete resolution of proximal weakness and ataxia was noted. Tremors, mild paraesthesia and grade 1/5 motor weakness in hand muscles persist despite 3-monthly parenteral thiamine and vitamin B12 therapy, oral thiamine (300 mg/day), vitamin B compound and Adcal D3.
Conclusion: Laboratory assessment of thiamine status is expensive, cumbersome and is not widely available. Normal serum thiamine level does not exclude thiamine deficiency and a high index of clinical suspicion is warranted to diagnose thiamine deficiency states (dry beriberi, wet beriberi and Wernicke Korsakoff syndrome). Biochemical and clinical monitoring of micronutrient deficiencies should be mandatory for all peri-operative bariatric surgery patients, preferably by adopting a locally agreed protocol.