Unmasking the Culprit of Profound Hyponatremia in an Infant

TL;DR

A 2-month-old infant with severe low sodium and an abdominal mass was diagnosed with a rare condition requiring urgent surgery.

Contribution

This case highlights hydrometrocolpos as a rare cause of profound hyponatremia in infants requiring emergency surgical intervention.

Findings

Severe hyponatremia in an infant was linked to a pelvic mass causing obstructive uropathy.

Hydrometrocolpos was identified as the underlying cause requiring urgent surgical treatment.

The infant showed significant improvement after intervention and supportive care.

Abstract

Infants with severe hyponatremia (Na < 120) and an abdominal mass require an astute clinical evaluation and often represent a medical emergency. We report a case of a 2‐month‐old White female, born full term, presenting with a two‐day history of decreased oral intake and urinary output, who was found to have severe hyponatremia with notable abdominal distention. Abdominal imaging revealed the presence of a pelvic mass causing obstructive uropathy. Further imaging and urogenital examination revealed a hydrometrocolpos. This rare entity required urgent surgical intervention and standard supportive care in the PICU. She had a subsequent significant improvement in symptoms and prevention of further deleterious complications.

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