Hypokalemic Periodic Paralysis in a 13-Year-Old Girl: Diagnostic Approach of Gitelman Syndrome

Background: Hypokalemic periodic paralysis is characterized by episodes of acute muscle weakness following decreased serum potassium levels due to primary or secondary cause. Identifying the cause of hypokalemia can be challenging and demands a thorough workup. Secondary hypokalemic periodic paralysis could be due to Gitelman syndrome, a rare autosomal recessive salt-losing renal tubulopathy. Laboratory abnormalities found in Gitelman syndrome are hypokalemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria. The disease is usually detected during adolescence or adulthood and the prevalence is estimated to be 1 in 40,000 individuals. Due to its low prevalence, Gitelman syndrome is rarely considered in the initial differential diagnosis of hypokalemia. Objective: The aim of this case report is to describe the diagnostic approach of Gitelman syndrome based on clinical and laboratory findings. Case: A 13-year-old girl was presented with recurrent acute episodes of muscle weakness of upper and lower limbs, without signs of gastrointestinal loss, inadequate intake, or past history of any medical prescription. On physical examination, blood pressure was slightly decreased, she had decreased power in all extremities, but it was more severe in the lower extremities. Physiological reflexes were diminished without sensory deficits. Laboratory tests revealed severe hypokalemia, metabolic alkalosis, and hypocalciuria. Glomerular filtration rate was normal. Renal ultrasonography showed no abnormalities. Thus, a diagnosis of Gitelman syndrome was made. The patient was treated with intravenous potassium replacement and showed remarkable recovery after five days. Treatment was continued with daily oral potassium. Conclusion: Investigations for the etiology of hypokalemic periodic paralysis should be carried out and consider Gitelman syndrome as a differential diagnosis. Gitelman syndrome can be diagnosed based on clinical and laboratory findings.