Life‐threatening hypokalemia in an infant (Case Presentation)

Abstract

The Discussion and Diagnosis can be found on page 1276. CASE Hypokalemia defined as serum potassium less than 3.6 mEq ⁄L is a common electrolyte abnormality encountered in everyday clinical practice. On the other hand, severe hypokalemia defined as serum potassium less than 2 mEq ⁄L is exceedingly uncommon. In the current report, we describe a 2.5-month-old boy who was urgently transferred to the pediatric intensive care unit (PICU) of the University Hospital of Heraklion from another regional hospital of Crete due to severe hypokalemia. The infant was the product of a twin gestation from a nonconsanguineous marriage and was born full-term weighing 2660 g. His twin sister was healthy. His medical history was remarkable for a small atrial septal defect that was diagnosed at birth and for which he was receiving no therapy. Upon arrival to the first hospital, the mother reported that the infant was felt warm to her for the last few hours, although no temperature was recorded at home, along with decreased oral intake and non-projectile vomiting, one to two episodes per day for the last 2 days. Family history was negative for hypokalemic periodic paralysis or other metabolic problems. In the referring hospital’s emergency room due to the infant’s age and history, despite the absence of fever, a rule out sepsis work-up was initiated that included a blood culture, a urinalysis (specific gravity 1020, pH 6, haemoglobin positive, protein 100 mg ⁄dL, nitrates negative, leucocytes 50–60 per HPF, erythrocytes 9 per HPF), a urine culture and a lumbar puncture that was traumatic (CSF with 200 leucocytes ⁄lL and 33 500 erythrocytes ⁄lL). A biochemical work-up revealed sodium 135 mEq ⁄L, potassium 1.8 mEq ⁄L, calcium 9.7 mg ⁄dL, phosphorus 4.8 mg ⁄dL, chloride 102 mg ⁄dL and magnesium 2.6 mg ⁄dL. The infant was started on intravenous ampicillin ⁄ sulbactam and ceftriaxone pending blood, urine, and CSF culture results. Due to the severe hypokalemia, a 1-mEq ⁄kg potassium chloride slow intravenous infusion was started and he was urgently transferred to the PICU. Upon admission to the PICU, the child was afebrile, mildly dehydrated, hypotonic, with high-pitched cry, normal blood pressure (84 ⁄41 mmHg), pulses 134 ⁄min, respirations 45 ⁄min and oxygen saturation 99% on room air. The infant’s weight on admission was 3880 g, that is 890 g less than his recorded weight 26 days ago. Physical examination revealed a 2 ⁄6 systolic heart murmur best heard on the second right intercostal space, without retractions or other signs of respiratory distress. Liver was palpable 2–3 cm below the right costal margin, while the skin, external genitalia and scrotum were normal. A complete blood count revealed leucocytes 12 600 ⁄lL with 62% lymphocytes, 20% neutrophils, 15% monocytes, 3% eosinophils, haemoglobin 9.3 g ⁄dL with MCV 83.6 fl, haematocrit 27.3% and platelets 574 000 ⁄lL. Hypokalemia was confirmed (initial serum potassium in the PICU 2.8 mEq ⁄L), while EKG monitoring revealed mild flattening of the T waves. Serum sodium was 139 mEq ⁄L, chloride 110 mEq ⁄L, calcium 8.6 mg ⁄dL, phosphate 3.3 mg ⁄dL, magnesium 2.8 mg ⁄dL along with glucose 130 mg ⁄dL, urea 6 mg ⁄dL, creatinine 0.4 mg ⁄dL, SGOT 41 IU ⁄L, SGPT 14 IU ⁄L, ALP 337 IU ⁄L, CPK 210 IU ⁄L and albumin 2.5 g ⁄dL. Arterial blood gases on room air revealed pH 7.45, pCO2 37 mmHg, pO2 100 mmHg and HCO3 25 mmol ⁄L. Coagulation studies were normal. A urine spot test revealed potassium 4.1 mEq ⁄L (normal 30–95 mEq ⁄L) along with sodium 4 mEq ⁄L, protein 1186 mg ⁄L, while Acta Paediatrica ISSN 0803–5253