Cistoscopia em posição quadrupedal para diagnóstico e remoção de cálculo vesical secundário a um gossipiboma em equino macho castrado

Resumo

Background: The formation of urinary calculi in horses has a low prevalence, with a higher incidence observed in males due to the greater length and narrower diameter of their urethras. Mineralization develops around a nidus, which may consist of a foreign body, cellular debris, or mucoproteins. The presence of a foreign body within the bladder induces local inflammation, which facilitates the deposition of mineral salts and subsequent calculus formation. In addition, foreign bodies can predispose to bacterial infections that alter urine pH, further enhancing mineral precipitation. Clinical signs of urinary calculi include dysuria, hematuria, and, in male horses, priapism. Diagnosis is based on clinical evaluation and imaging techniques such as cystoscopy. Treatment in males is generally surgical. This report describes a case of vesical calculus secondary to a foreign body in a gelding, highlighting the importance of cystoscopy as both a diagnostic and therapeutic tool.

Case: An 8-year-old Criollo gelding was admitted to the Veterinary Hospital of the Federal University of Paraná (HV-UFPR) with a one-year history of reddish urine which was exacerbated with exercise. The horse had been castrated in the field by a non-veterinary practitioner, six years prior. The complete blood count revealed no significant abnormalities. However, urinalysis showed turbid, alkaline urine with abundant erythrocytes and calcium carbonate crystals, confirming hematuria. For a definitive diagnosis, cystoscopy was performed, which is considered the most accurate imaging modality. The examination, performed on the standing animal under sedation via the penile urethra, revealed the presence of multiple vesical calculi and a filamentous foreign body firmly adhered to the bladder mucosa. Cystoscopy was used for both diagnosis and treatment procedures. During the procedure, the foreign body, which was later identified as a cotton thread, was removed. The uroliths were fragmented and extracted using a polypectomy snare, and a thorough bladder lavage was performed to eliminate smaller fragments and mitigate the risk of recurrence. The formation of the calculi was attributed to the cotton thread, which acted as a nidus for mineral deposition. The animal had a favorable post-operative recovery and was discharged one week after the procedure.

Discussion: Despite the low prevalence of equine urolithiasis, this case demonstrates the rare occurrence of calculi associated with a foreign body. The animal’s intermittent hematuria justified performing a cystoscopy, which proved to be an accurate diagnostic method for identifying both the uroliths and the cotton thread acting as the nidus for mineralization. It is believed that the thread, a probable remnant from the field castration, migrated into the bladder. In cases of gossypiboma, as observed in the present case, malleable foreign bodies can induce tissue ischemia and necrosis, allowing their migration into the lumen of organs such as the urinary tract, a phenomenon previously reported in humans. Although urolith formation in horses is uncommon, early and accurate diagnosis is essential. In this case, it is believed that a cotton thread from a previous castration acted as both a foreign body and a nidus for calculus formation in the bladder. Cystoscopy, performed on the standing animal, proved to be a highly effective and comprehensive technique. This modality was utilized not only for definitive diagnosis, allowing direct visualization of the urinary tract, but also for treatment through the removal of the calculi. This case highlights cystoscopy’s superior efficacy as a minimally invasive and safe diagnostic and therapeutic tool for equine patients.