To illustrate our experience with two cases of neonatal life-threatening hyperkalemia during therapeutic hypothermia (TH) despite a normal acid-base status, urine output, and preserved renal function. Clinical cases are presented from Pediatric Intensive Care Unit (PICU) admission to the onset of the hyperkalemia, with related complications and after resolution. Similar cases were not retrieved from a critical review of pertinent literature. Severe hyperkalemia pathophysiology and risk factors have been debated. Two full-term adequate for weight female neonates were admitted to PICU because of perinatal asphyxia who underwent TH. Prenatal history was completely uneventful, nor hereditary genetic conditions were reported; moreover, long-term follow-up ruled out any metabolic or renal disease. Despite an accurate evaluation of previous clinical series and literature on TH and perinatal asphyxia, these hyperkalemic episodes remain unexplained. The hypoxic-ischemic insult may affect multiple organs, mainly central nervous system, heart, lung, and kidneys; acute muscle breakdown and consequent rising of myoglobin may also have a precipitating role in acute kidney failure (AKF) and hyperkalemia. Electrolyte imbalance is a possible finding as a consequence of combined cell injury and AKF. In contrast, an isolated severe hyperkalemia is exceedingly rare in nonoliguric neonates.
Keywords: neonates; nonoliguric hyperkalemia; perinatal asphyxia; therapeutic hypothermia.