First Onset Hypokalemic Periodic Paralysis Following Surgery for Myxopapillary Ependymoma, Case Report

Background: Hypokalemic periodic paralysis is a rare skeletal muscle channelopathy characterized by intermittent episodes of acute flaccid paralysis with associated hypokalaemia. We present here the case of a first-onset hypokalemic periodic paralysis triggered by a lumbar spinal surgery for tumor resection.

Case description: A 37-years old male, without any known prior medical conditions who 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 an spinal cord compression and while en route for imaging an abrupt onset of flaccid paralysis with significant respiratory distress. The emergency blood test revealed extreme hypokalemia with a serum potassium of 1.42 mm/L. The patient was transferred to ICU unit, intubated, sedated, and intravenous reperfusion with an infusion dose of 20 mEq/h potassium in a solution of 5% mannitol was administered. 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 the mutation of the CACNA1S gene.

Conclusions: To the best of our knowledge, this is the first described case with the first onset triggered by a neurosurgical intervention and the second one following any kind of surgery. Neurosurgeons should consider hypokalemic periodic paralysis when encountering a rapidly evolving tetraparesis, even in an apparently completely healthy patient.

Keywords: Hypokalemic Periodic Paralysis; Microneurosurgery; Myxopapillary Ependymoma.