ABladder rupture is a tear or leak in the urinary bladder that results in uroperitoneum. Uroperitoneum, the accumulation of urine in the peritoneal (abdominal) cavity, also can result from disruption of other parts of the urinary tract. It is difficult to predict when bladder ruptures might occur; thus, it is difficult to prevent. Although bladder ruptures can occur in adult horses, usually from urinary tract obstruction, the vast majority of bladder ruptures occurs in foals. The rupture in foals usually occurs in the bladder itself, but also can occur in the urachus. The urachus, a structure in the fetus which lies between the tip of the bladder and the umbilical cord, allows the excretion of urine. This structure normally is closed at birth, and over several weeks contracts to a thick band of tissue.

Most bladder ruptures in foals occur during parturition. It is thought that the increased abdominal pressure the foal experiences during birth can lead to rupture of a full bladder if urine cannot be easily voided. The anatomy of the male pelvis and the longer length of the male urethra tend to predispose the male foal to this problem more often than the female.

Clinical signs seen in foals with bladders that rupture during parturition appear within the first two or three days of birth. The foal might become dull and depressed. There can be abdominal distension. Sometimes the foal will be colicky. Even though most of the urine is entering the abdominal cavity rather than exiting through the urethra, the foal often will dribble urine because the urethra is patent (not closed). You don’t usually see a steady stream of urine from these foals