Improvement of the exercise test after therapy in thyrotoxic periodic paralysis

Muscle Nerve. 1992 Oct;15(10):1069-71. doi: 10.1002/mus.880151002.


The diagnosis of periodic paralysis (PP) can be aided by demonstrating a decrease in compound motor action potential (CMAP) amplitude after several minutes of exercise. We report a case of secondary hypokalemic PP due to thyrotoxicosis in which the decrease in the CMAP amplitude after exercise dramatically improved after treatment, when a euthyroid state was achieved. The exercise test is a useful electrophysiologic means of monitoring the neuromuscular status of patients with thyrotoxic periodic paralysis prior to, and after treatment of the thyrotoxicosis.

Publication types

  • Case Reports

MeSH terms

  • Action Potentials
  • Adult
  • Electromyography
  • Exercise Test
  • Humans
  • Hypokalemia / etiology
  • Iodine Radioisotopes / therapeutic use
  • Male
  • Muscles / physiopathology
  • Paralysis / diagnosis*
  • Paralysis / etiology
  • Thyrotoxicosis / complications*
  • Thyrotoxicosis / diagnosis
  • Thyrotoxicosis / radiotherapy


  • Iodine Radioisotopes