Grand Rounds

Pseudohypoaldosteronism Secondary to Urinary Tract Infection in a Premature Newborn Baby

Samet Benli, Erdal Taşkın, Mustafa Aydın
Department of Neonatology, Firat University School of Medicine, Elazig, Turkey

Address for Correspondence: Samet Benli, Department of Neonatology, Firat University School of Medicine, 23200, Elazig / Turkey. Email: drbenli@gmail.com

Keywords: Pseudohypoaldosteronism Secondary, Urinary Tract Infection, Newborn

Clinical Problem:
Upon the detection of sodium 120 mmol/L and potassium 8.8 mmol/L in the routine examinations taken on the 93th day of hospitalization of a premature baby born at the 24th gestational week, weighing 700 g (Figure 1), further investigations for the etiology were performed.
The patient has been fed full enteral (8x70 cc) with an orogastric tube. The patient who was operated on postnatal 14th day for intestinal perforation had ileostomy. Tracheostomy was performed on the postnatal 78th day of the patient who developed posthemorrhagic hydrocephalus during the clinical follow-up and could not be extubated. The patient is still on mechanical ventilation (PIP 23, PEEP 6, IT 0.40, and FiO2 30%). Of the vital signs, body temperature was 36.3 degrees Celsius, heart rate 126 beats/min (range 120-160), oxygen saturation 93% (range 90-94) and blood pressure 87/46 (mean 62) mmHg. There was no any central catheter other than the previously inserted umbilical venous catheter.
His previous sodium and potassium levels were within normal limits. Capillary blood gas analysis was consistent with metabolic acidosis (pH 7.28, pCO2 26.1, HCO3 16.2). The patient’s other laboratory parameters were normal as follows: hemoglobin 10.3 g/dL (range 14-23.7 g/dL), hematocrit 32% (range 47-75%), white blood cells 16.2x103 cells/µL (range 9-30 cells/µL), platelets 608x103 cells/µL (range 150-400 cells/µL) , Cl 90 mmol/L (range 98-110 mmol/L), BUN 30 mg/dl (range 10-50 mg/dL), creatinine 0.5 mg/dl (range 0.2-0.9 mg/dL), eGFR 24 ml/min (range ~20 ml/min per 1.73 m2), and C-reactive protein 62 mg/L (range 0-5). In spot urine, sodium was <10 mEq/L (range 54-150 mEq/L), potassium 13.3 mEq/L (range 20-80 mEq/L), calcium <1 mg/dL (range 6.7-21.3) and protein 37.4 mg/dL (range 1-14 mg/dL). Urinalysis was consistent with urinary tract infection (leukocyte esterase +3, nitrite positive, protein trace; leukocyte 217/HPF (range <5/HPF), erythrocyte 20/HPF (range <3/HPF) and bacteria 5/HPF). On further laboratory analysis, 17-hydroxyprogesterone was 5.1 nmol/L (range 0.3-5.2), renin 100 ng/mL (range 2.4-37) and aldosterone >1000 ng/dL (range 7-99). 105 colonies of Klebsiella pneumonia were isolated in the urine culture, and after that ceftazidime/avibactam treatment was started according to the antibiogram. Urinary ultrasonography showed signs of urinary tract infection. Insulin-glucose infusion and sodium bicarbonate treatment was given for hyperkalemia. Replacement was given for hyponatremia, and then 2 g/day of salt was added to his diet. The urinary tract infection resolved after antibiotic treatment, and sodium and potassium levels returned within normal limits on the 10th day of treatment. Afterwards, the patient’s salt support was gradually reduced and discontinued.
In this context, what should we consider in the etiology for hyponatremia, hyperkalemia and metabolic acidosis that occurred during follow-up in this patient?

Figure 1. General appearance of the patient.

What should we consider in the etiology that occurred during follow-up?