A Pediatric Case of Hypokalemic Periodic Paralysis With Fatigue and Myalgia.

Periodic paralysis is a rare genetic disorder characterized by recurrent episodes of sudden skeletal muscle weakness. Various factors can trigger this condition, including cold temperatures, abnormal potassium levels, physical activity, and consumption of certain foods. Periodic paralysis is considered benign and usually manifests as muscle weakness. Adult patients with hypokalemic periodic paralysis often experience symptoms such as myalgia and fatigue, whereas myalgia and fatigue are less common in children. We encountered a pediatric patient with hypokalemic periodic paralysis who presented with weakness, general fatigue, and widespread myalgia. The patient was a girl ten years and six months old, admitted to our hospital with generalized muscle weakness after exercise. Her maternal relatives exhibited similar symptoms, including weakness. The patient had hypokalemia but normal thyroid hormone levels. After her serum potassium level was corrected with infusion, her trunk strength and her symptoms resolved. Genetic testing revealed a mutation in CACNA1S, leading to a diagnosis of hereditary hypokalemic periodic paralysis. Occasionally, she experienced persistent general fatigue and widespread pain in her neck, shoulders, arms, lower back, and legs without paralysis or hypokalemia for several days. In conclusion, adult patients with periodic hypokalemic paralysis often experience myalgia and fatigue. Although myalgia and fatigue are rare in pediatric patients, periodic paralysis should still be considered in the differential diagnosis, even in children who show symptoms of muscle pain and fatigue without actual muscle weakness.