Hyperkalemia in young children: blood pressure checked?

Hyperkalemia in young children is a rare phenomenon and in many cases caused by hemolysis in the specimen due to difficulties in obtaining a sample. However, hyperkalemia can also be a sign of a rare Mendelian syndrome known as familial hyperkalemic hypertension or pseudohypoaldosteronism type II. This disease is characterized by hyperkalemia, hypertension, and mild hyperchloremic metabolic acidosis (with normal anion gap) despite normal glomerular filtration. Full recovery of these abnormalities with thiazide diuretics is essential not to miss the diagnosis of this syndrome. We describe two young patients with hyperkalemia as an incidental finding who were subsequently diagnosed with this rare endocrine disorder. Genetic testing revealed mutations in two recently discovered genes, the study of which has helped to unravel the pathophysiologic pathways. CONCLUSION: In patients with hyperkalemia and a normal glomerular filtration rate, the clinician should actively search for abnormalities in blood pressure since recognizing this condition can lead to simple, cheap, and effective treatment. What is Known: • True Hyperkalemia is rare in pediatrics and can be a sign of FHHt. What is New: • KLHL3 & CUL3 are recently discovered genes helping unravel the pathophysiologic pathway of FHHt.