Transient thyrotoxicosis‐aggravated attacks of paralysis in a patient with hereditary hypokalemic periodic paralysis type 2

Abstract

We report a case with hereditary hypokalemic paralysis type 2 in whom thyrotoxicosis aggravated his attacks of paralysis. He experienced paralytic attacks several times a year from 24 years of age and was clinically diagnosed with hypokalemic periodic paralysis. At 49 years of age, a laboratory examination showed normal thyroid function. At 57 years of age, transient thyrotoxicosis was accompanied with an increase of the frequency and severity of attacks. Gene analysis revealed a missense mutation (c.2015G>A, p.R672H) in SCN4A, a known pathogenic mutation for hypokalemic paralysis type 2. This case highlights the importance of checking thyroid function when the frequency and severity of attacks are increased in patients with periodic paralysis.