Distal urethral obstruction in an eight‐week‐old colt with struvite urolithiasis

Summary An 8‐week‐old Thoroughbred colt presented with acute colic signs. Physical examination and transcutaneous ultrasound of the abdomen and penis revealed a urinary tract obstruction in the distal urethra due to urolithiasis. A distal urethrotomy over the site of obstruction was performed to remove the urolith and relieve the obstruction. Analysis of urolith constituency revealed the presence of pure magnesium ammonium phosphate hexahydrate (struvite). Urinalysis identified a lower urinary tract infection (UTI) with the presence of urease‐producing bacteria. Patent urinary flow via the urinary catheter was present immediately after surgery. Urinary catheterisation was discontinued after 36 h, and the foal resumed normal micturition. The foal was discharged after 5 days. At telephone follow‐up 12 months later, the owner reported no recurrence of urolithiasis or altered micturition. At the time of authorship, this report describes the youngest case of urolithiasis in equids documented in the literature and features an atypical crystalloid composition of the urolith. The report highlights the potential for urolith development in young foals with concurrent lower UTI and urethral obstruction as a differential for colic in foals.