BACKGROUND: Urinary tract infections and/or urinary tract anomalies are very frequent among children. Especially in newborns/infants they represent additional factors in the development of secondary pseudohypoaldosteronism. CASE HISTORY: We present an 8-week-old infant who developed hyponatremia and hyperkalemia secondary to acute pyelonephritis. The boy presented with non-specific signs, including poor appetite, lethargy, and hypotonia. An extended evaluation led to the diagnosis of pseudohypoaldosteronism (PHA). PHA was transient and during therapy of pyelonephritis all of abnormal laboratory parameters returned to normal. The patient had vesico-ureteric reflux grade IV. CONCLUSION: Secondary/transient/reversible PHA occurs in patients with immature renal tubular responsiveness to aldosterone due to infancy when they have urinary tract anomalies and/or urinary tract infection. (Tab. 1, Ref. 7.)

2nd Department of Pediatrics University Hospital Brno Czech Republic