First-Onset Hypokalemic Periodic Paralysis Following Surgery for Myxopapillary Ependymoma.

Abstract

Hypokalemic periodic paralysis is a rare skeletal muscle channelopathy characterized by intermittent episodes of acute flaccid paralysis with associated hypokalemia. We present here the case of a first-onset hypokalemic periodic paralysis triggered by lumbar spinal surgery for tumor resection. A 37-year-old male without any known prior medical conditions presented with a first-onset attack of hypokalemic paralysis 1.5 days after lumbar spinal surgery for myxopapillary ependymoma. Initially, the patient presented paraparesis mimicking a spinal cord compression, and while en route for imaging there was an abrupt onset of flaccid paralysis with significant respiratory distress. The emergency blood tests revealed extreme hypokalemia with a serum potassium of 1.42 mm/L. The patient was transferred to the intensive care unit, intubated, sedated, and administered intravenous reperfusion with an infusion dose of 20 mEq/hour potassium in a solution of 5% mannitol. Following reperfusion, the patient recovered completely in 12 hours. Renal potassium hyperexcretion and hyperthyroidism were excluded by laboratory tests. The diagnosis was confirmed by genetic tests showing mutation of the CACNA1S gene. To the best of our knowledge, this is the first described case with the first onset triggered by a neurosurgical intervention and the second case following any kind of surgery. Neurosurgeons should consider hypokalemic periodic paralysis when encountering a rapidly evolving tetraparesis, even in an apparently healthy patient.