Hematocolpos: An Uncommon Cause of Acute Urinary Retention and Hydronephrosis.

Acute urinary retention is uncommon in pediatric age and is usually associated with infection or obstruction of the urinary tract. We present the case of a 12-year-old girl admitted to the emergency room with acute urinary retention and lower urinary tract symptoms. Physical examination revealed abdominal distension and a blue-bulging mass occupying the vaginal introitus. Ultrasound confirmed the diagnosis of hematocolpos and revealed hydronephrosis, caused by compression. Kidney function and urinalysis were normal. A hymen incision and excision of redundant tissue were performed without complications. Hematocolpos is a condition caused by obstructive uterovaginal deformity. Imperforate hymen is responsible for most of the cases and usually manifests as primary amenorrhea and cyclic lower abdominal pain. The diagnosis of hematocolpos can be challenging. However, it is important to consider it in female adolescents without menarche presenting with acute urinary retention.