COVID-19 infection and intense physical activity in hypokalemic periodic paralysis.

Background: Hypokalemic periodic paralysis (HPP) is a rare genetic neuromuscular disorder characterized by an autosomal dominant inheritance pattern and a variable clinical phenotype. It is associated with low potassium levels due to defects in muscle ion channels. HPP can be life-threatening, but it can be completely reversed if diagnosed and treated promptly and correctly. Pathogenic variants in a heterozygous in the CACNA1S or SCN4A genes lead to HPP.

Clinical case: We present a 16-year-old male with a clinical history of flaccid paralysis associated with hypokalemia following intense physical activity and subsequent COVID-19 infection. During this evaluation, his 12-year-old maternal half-brother exhibited similar symptoms related to intense physical exercise. The affected mother, maternal aunt, and maternal grandfather have variable clinical histories. Genetic testing identified a heterozygous pathogenic variation in the CACNA1S gene (c.2700G>A; p.Arg900Ser) in the patient, his mother, and maternal half-brother.

Conclusion: The availability of a positive family history facilitates diagnostic guidance and provides insight into the factors triggering crises. Education is the first step in contributing to prevention and management. Furthermore, understanding the etiological cause is crucial for offering available therapeutic options and providing family genetic counseling.