Magnesium deficiency: a possible cause of thiamine refractoriness in Wernicke-Korsakoff encephalopathy.

The determination of blood transketolase before and serially after thiamine administration, and the response of clinical symptomatology after thiamine are reported in two normomagnesaemic patients and one hypomagnesaemic patient with acute Wernicke-Korsakoff encephalopathy. The response of the depressed blood transketolase and the clinical symptoms was retarded in the hypomagnesaemic patient. Correction of hypomagnesaemia was accompanied by the recovery of blood transketolase activity and total clearing of the ophthalmoplegia in this patient, suggesting that hypomagnesaemia may be a cause of the occasional thiamine refractoriness of these patients.