A 13 year old young girl presents to the casualty with acute pain in the lower abdomen. She has history of cyclical pain for last 6 months and she has not attained her menarche yet. On local genital examination, a tense bulge in the region of hymen is seen. The most probable diagnosis is :

Imperforate Hymen The hymen is formed by invagination of the posterior wall of the urogenital sinus Typically patients presents at the expected time of menarche with complaints of cyclic perineal, pelvic or abdominal pressure or pain which results from the gradual accumulation of obstructed menstrual flow (cryptomenorrhea), and normal symmetrical secondary sexual development for age They may also present with acute urinary retention due to compression of the urethra and bladder by a grossly distended lower vagina The genital examination reveals a thin bulging, blue perineal membrane at the inferior limit of a palpable, fluctuant mass (hematocolpos) Definitive surgery should be accomplished as soon as possible because delay can lead to infeility due to inflammatory changes and development of severe endometriosis The classical procedure is to make a simple cruciate incision in the hymen to the base of the hymeneal ring and to excise its central poion to allow drainage of sequestered menstrual fluid and subsequent normal menstruation Alternatively, to avoid any risk of damage to the hymeneal ring (a sign of virginity), a sterile puncture can be made in the center of the distended membrane and enlarged to approximately 0.5 cm in diameter to allow inseion of a 16F Foley catheter After thorough drainage of the vagina irrigation with sterile saline, the catheter is left in place for approximately 2 weeks to allow fuher drainage from the vagina and upper genital tract Ref: Clinical Endocrinologic Gynecology and Infeility; Eigth edition; Chapter 11