Diagnosing Poor Performance: A Case Report
By Harry Werner, VMD, WEVA Board Member

History: An owner reported that a 14-year-old Warmblood gelding would stop intermittently while working under saddle. While he displayed no colic signs, his owner noticed occasional episodes of dark-brown urine. He had no fever, and his appetite was normal.

Examination: The veterinarian deemed the horse’s physical examination unremarkable. He did not resent pressure over his back, and he showed no lameness.

Ancillary Diagnostics: The practitioner then turned to urinalysis and urine bacterial culture, which revealed blood but no evidence of infection. The horse’s complete blood count and serum chemistry panel were normal.

A subsequent videoendoscopic examination of his urinary bladder (called cystoscopy, pictured above left) revealed multiple abrasions of the bladder’s mucosal lining, which resulted from the presence of a rough-surfaced stone (left).

Diagnosis: Urinary bladder stone (cystolith)

Treatment: A surgeon removed the stone and flushed the bladder, which restored the horse’s urinary tract to normal.

Discussion: Urinary bladder stones in horses are primarily a concretion of calcium salts and are found much more frequently in stallions and geldings than in mares. The mare’s shorter and wider urethra allows small stones to be excreted before they grow too large. This gelding’s behavior of stopping suddenly at the trot no doubt resulted from the pain produced by the rough surface of the stone moving within his urinary bladder. Once other potential issues were ruled out, diagnosis was relatively easy, as cystoscopy is a safe, quick, and highly accurate stall-side method of examining the equine bladder for pathology. Once a horse has been diagnosed with bladder stones, owners and veterinarians should attempt to keep urine dilute and acidic. Our practice recommends removing legume hay from the diet due to its high calcium content.