J Electrodiagn Neuromuscul Dis.  2021 Dec;23(3):71-75. 10.18214/jend.2021.00052.

Progressive Muscular Atrophy with Hypokalemic Periodic Paralysis: A Case Report

• Bae YK
• Lee JH
• Sim YJ
• Jeong HJ
• Kim GC

• KMID: 2526155
• DOI: http://doi.org/10.18214/jend.2021.00052

Abstract

Progressive muscular atrophy (PMA) is a rare disease involving lower motor neuron degeneration. Hypokalemic periodic paralysis (HypoPP) is a genetic disorder that causes temporary muscle paralysis due to decreased serum potassium levels. Mutations in the CACNA1S gene cause HypoPP. An altered locus closely linked near the CACNA1S gene suggests the possibility of motor neuron degeneration. However, PMA with HypoPP is very rare worldwide because HypoPP usually causes progressive muscle weakness involving a form of myopathy without motor neuron disease. In this report, we describe the case of a 64-year-old man who initially complained of weakness in only the left lower extremity, which subsequently progressed bilaterally. Hence, the patient was diagnosed with PMA with HypoPP based on serial electromyography and the presence of a CACNA1S mutation. Therefore, serial electromyography is necessary for middle-aged patients with progressive muscle weakness and a history of HypoPP.

Keyword

Progressive muscular atrophy; Hypokalemic periodic paralysis; Electromyography