Rapidly progressive polyneuropathy due to dry beriberi in a man: a case report

INTRODUCTION We describe a case of rapidly progressive and severely debilitating polyneuropathy in a patient with confirmed hypovitaminosis B1, consistent with dry beriberi. Crucially, this is a treatable condition, although sometimes with incomplete recovery, but it is probably under-recognized yet increasingly common given increasing levels of alcohol abuse in the western world. CASE PRESENTATION A 49-year-old Caucasian British man presented with progressive weakness of both lower limbs of approximately seven months' duration. He noted difficulty climbing stairs. He also complained of lethargy, and loss of muscle bulk, including his thighs. He had a history of type 2 diabetes mellitus and admitted prior alcohol abuse but denied excessive alcohol intake in the five years prior to presentation. Initial clinical and neurophysiological examinations were consistent with a mild peripheral neuropathy and probable proximal myopathy. However, over the subsequent four months he evolved a marked tetraparesis, with profound sensory disturbance of all limbs. Repeat neurophysiology revealed a widespread polyneuropathy with extensive acute and sub-acute denervation changes in all four limbs, and reduced or absent sensory nerve action potentials. Hypovitaminosis B1 was confirmed (45 nmol/L, reference range 66-200 nmol/L). His rapid clinical deterioration was in keeping with dry beriberi. He was treated with thiamine. Subsequent follow-up revealed slow but significant improvement, such that by 15-16 months from the initial onset of symptoms, and approximately six months after the onset of his marked tetraparesis, he was able to stand independently and was gradually gaining confidence in walking pending a period of in-patient neurorehabilitation. CONCLUSION A potentially wide differential diagnosis exists for this type of presentation. Confirming hypovitaminosis B1 by requesting the assay prior to vitamin replacement ensures accurate diagnosis and appropriate ongoing treatment. An increasingly high index of suspicion is likely to be required in the context of increasing levels of alcohol abuse in the western world and the possible increasing prevalence of dry beriberi.