Urinary incontinence in a pony mare.

The study examines a case of urinary incontinence in a pony mare, which was associated with a severe respiratory disorder. Using a range of diagnostic tools, the researchers detected an unusual increase in bladder and rectal pressures during coughing but an absence of increased pressure within the urethra.

Urinary Incontinence and Respiratory Illness in Pony Mare

• The researchers focused on a 12-year-old obese pony mare. The pony showed clear signs of severe bronchitis and marked abdominal contractions during expiration. A significant symptom was urinary incontinence during coughing.
• Examination of the mare’s upper respiratory tract, urethra, and bladder was carried out using a fiber-optic endoscope. The results showed symptoms typical for laryngitis and tracheitis in the upper respiratory tract, but no clear signs of any pathology were identified in the urethra and bladder.

Urodynamic Measurements

• To better understand the urinary incontinence, tests were carried out to measure and record the internal pressure inside the bladder, urethra, and rectum. Two catheters were used, inserted into the rectum and through the urethra into the bladder respectively. The catheters were connected to a device to measure the pressure changes within these areas.
• The resting and induced pressure changes were noted over a period of no less than 25 minutes while the mare was in a relaxed state. Pressure changes during induced coughing were also recorded. An attempt was made to record pressures as the catheters were slowely withdrawn, but it failed due to difficulties holding the catheter in place within the urethra during the cough.

Results of Urodynamic Measurements

• The resting pressure in the mare’s rectum was found to be approximately 10 cm H2O below atmospheric pressure, and the resting intrabladder pressure was 4 cm H2O above atmospheric pressure.
• During a cough, pressure within the bladder and rectum increased simultaneously by approximately 200 cm H2O. Notably, the pressure within the urethra didn’t rise significantly above the bladder pressure at any point during the withdrawal of the catheter from the incontinent mare.
• Comparative measurements taken 16 weeks later showed a distinct increase in the urethral pressure above the bladder pressure. Significant changes in pressure were also found in the rectum and urethra of a healthy (continent) mare during induced coughing.