Perirectal abscess as suspected cause of bladder rupture in a foal

A 4-month-old colt foal was admitted to the hospital with a history of acute stranguria and colic signs. On presentation, he was tachycardic, tachypnoeic and pyrexic. Blood work showed marked leucocytosis and severe azotaemia. Ultrasound examination of the abdomen revealed a reduced bladder lumen and a large volume of free peritoneal fluid. Abdominocentesis confirmed uroperitoneum. The foal underwent a general anaesthetic to repair the bladder. Unfortunately, the following day, the uroperitoneum recurred, so a revision surgery was performed. The bladder wall was repaired and a large impaction of the terminal small colon and rectum was diagnosed at this point. Rectal examination post-operatively revealed a spherical mass compressing the dorsal aspect of the rectum, which reduced its diameter by approximately 75%. Ultrasound examination, cytology and culture of a fine-needle aspirate of the mass revealed it to be a perirectal abscess, and this was drained per rectum and lavaged several times. The foal recovered well, regained the ability to micturate and remained healthy at subsequent post-operative checks. It is suspected that the perirectal abscess led to overdistention and subsequent rupture of the bladder.