Distal Renal Tubular Acidosis in Pregnancy: A Case Report and Systematic Literature Review

Distal renal tubular acidosis (dRTA) is a rare disorder characterized by normal anion gap metabolic acidosis and hypokalaemia. Physiological changes during pregnancy may aggravate acid-base imbalance and influence foetal outcomes.

A 40-year-old pregnant woman at 24-25 weeks of gestation presented with recurrent hypokalaemia and lower limb weakness. Laboratory findings showed normal anion gap metabolic acidosis, consistent with dRTA. The patient was treated with oral potassium supplementation and intravenous sodium bicarbonate, resulting in clinical improvement. In the third trimester, intrauterine growth restriction was identified. Delivery at term resulted in a live neonate with low birth weight.A literature review was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines using PubMed, ScienceDirect, Wiley Online Library, SpringerLink, and ResearchGate for studies published between 2016 and 2026. Ten case reports met the inclusion criteria. Distal RTA was the most frequently reported subtype, accounting for 80% of cases. Most cases (70%) were first diagnosed during pregnancy. The most common treatment strategy was potassium supplementation combined with bicarbonate therapy (90%), administered either orally, intravenously, or as combination therapy. Adverse neonatal outcomes were reported in 50% of cases.

Distal RTA should be considered in pregnant patients presenting with recurrent hypokalaemia and muscle weakness. Early recognition and appropriate correction of electrolyte imbalance and metabolic acidosis are essential to optimize maternal and foetal condition. Further studies are needed to better define clinical characteristics and management strategies of renal tubular acidosis during pregnancy.

Vigilance is essential for rare distal renal tubular acidosis (dRTA)-pregnancy overlap As the leading form of RTA, (seen in 80% of reported cases), distal RTA (dRTA) frequently first appears during pregnancy (70% of instances), where it closely resembles routine hypokalaemic conditions. Clinicians should routinely check for anion-gap metabolic acidosis in pregnant women experiencing repeated muscle weakness, allowing timely treatment to avert severe maternal decline.Bicarbonate and potassium therapy boosts maternal-foetal success In this case, combined oral and intravenous replacement (effective in 90% of documented scenarios) quickly alleviated symptoms, yet the 50% chance of neonatal issues like intrauterine growth restriction or low birth weight underscores the approach's value for the foetus, providing internists with a reliable, safe strategy amid pregnancy's natural acid-base changes.Diagnostic pathway to reveal hidden dRTA dangers This experience arms internists with a straightforward algorithm (start with hypokalaemia evaluation, advance to acidosis testing) that cuts late-pregnancy risks, especially in settings with limited resources.