A 34-year-old Gravida 5 para 4 came at 32 weeks gestation for threatened preterm labor in association with pruritus and decreased fetal movement.

Her past medical history was significant for childhood pseudohypoaldosteronism type 1, which had resolved spontaneously at the age of 5.

She was a known case of cholelithiasis and gestational diabetes on metformin and insulin. Her obstetric history included four cesarean sections, a previous neonatal death from congenital heart disease, and two previous episodes of obstetric cholestasis and gestational diabetes. No previous similar recurrence of PHA was reported in her earlier pregnancies.

Her second-trimester anomaly scan at 20 weeks was unremarkable, with fetal biometry consistent with gestational age. On admission, the patient had a good hemodynamic status with a blood pressure of 115/77 mmHg, a pulse rate of 104 beats/min, and a respiratory rate of 15 breaths/min.

Her symphysio-fundal height measured 29 cm. CTG showed regular contraction (one in 10 min) with a normal basal heart rate and variability. The cervical os was closed. Admission laboratory tests documented severe electrolyte disorder: hyperkalemia (K + 5.6 mmol/L), hyponatremia (Na + 128 mmol/L), and low bicarbonate (18.7 mmol/L).

Liver function tests showed elevated transaminases (AST 117 U/L, ALT 190 U/L) and bile acids (22.5 µmol/L). The patient was hospitalized due to the threatened preterm labor, and tocolysis with Atosiban, magnesium sulfate for fetal neuroprotection, and betamethasone for fetal lung maturity were administered.

Ursodeoxycholic acid was initiated for obstetric cholestasis. Her initial laboratory investigations revealed hyperkalemia, hyponatremia, hypercalcemia, and elevated liver enzymes, prompting regular monitoring of her labs as summarized in Table 1 below:

Table 1 Key laboratory trends from admission to discharge

During her admission, her condition worsened with dangerously peaked electrolyte levels: potassium to 6.2 mmol/L, sodium dropped to 124 mmol/L, and bicarbonate fell to 15 mmol/L, requiring transfer to the intensive care unit. Arterial blood gas analysis indicated compensated metabolic acidosis.

Diabetic ketoacidosis was ruled out based on normal glucose levels and absence of ketonuria. Other common causes of hyperkalemia, such as renal failure, adrenal insufficiency, and medication-induced causes (e.g., potassium-sparing diuretics, ACE inhibitors), were also ruled out based on normal renal function tests and the absence of a relevant drug history. The electrolyte abnormalities persisted despite aggressive therapy, including the infusion of insulin/dextrose, calcium gluconate for cardio protection, and sodium bicarbonate and a potassium-free diet.

At that time, the patient’s father (a physician) provided us with additional information on the child’s medical history, for which she had a history of PHA and was treated with NaCl tablets and K binds until self-limited resolution at 5 years of age. A similar condition had affected her brothers/sisters and relatives that were resolved spontaneously by early childhood. This crucial history, in the context of the unexplained electrolyte imbalances, led to the specific hypothesis of PHA1 reactivation. Elevated aldosterone level was subsequently measured and confirmed the diagnosis of PHA type1 (Table 2).

Table 2 Confirmatory hormonal assays

A multidisciplinary team comprising intensivists, obstetricians, endocrinologists, and dietitians was assembled to manage this complex case. The patient was placed on an oral salt supplementation regimen combined with a low-potassium diet, which gradually led to normalization of her electrolyte levels. Throughout her hospitalization, she remained asymptomatic with normal electrocardiogram findings.

Obstetric ultrasound confirmed fetal growth restriction, with an estimated fetal weight of 1459 g (< 10th percentile). Initial Doppler studies were unremarkable. After 10 days of inpatient care, the patient was discharged with a serum potassium level of 4.5 mmol/L and continued regular antenatal follow-up at a joint diabetes and high-risk pregnancy clinic.

At 36 weeks’ gestation, she presented with reduced fetal movements. Cardiotocography (CTG) revealed reduced short-term variability and recurrent late decelerations, prompting an emergency cesarean section for a non-reassuring fetal status. This timely intervention likely prevented progression to significant fetal acidosis and resulted in the delivery of a vigorous 2190-gram female infant, whose weight represented the 7th percentile on the WHO growth chart. The newborn had excellent outcomes, with Apgar scores of 9 and 10 at 1 and 10 min, respectively, and a normal cord blood pH. Both mother and baby had stable electrolytes postpartum and were discharged home on the second postnatal day without complications.