Urethropreputial Fistula in a Mixed Breed Dog - Urethrostomy

Abstract

Background: Urethropreputial fistulas are communicative conduits between the urethra, prepuce, and environment whose origin deviates the urinary flow from its physiological path. The condition has a multifactorial cause and is considered uncommon in dogs. By the scarce occurrence of this malformation, as well as the scarcity of case reports on the subject, the present work aims to report a case of congenital urethropreputial fistula in a mixed breed dog and the surgical procedures performed to correct this genitourinary abnormality. In addition, it seeks to cross information available in the literature with the changes found during the case attendance.

Case: An approximately 1-year-old male canine, mixed breed, was attended at the Veterinary Hospital of the Federal Rural University of Pernambuco (HOVET - UFRPE) with a complaint of dysuria, where the urinary flow occurred by dripping through an orifice caudal to the external urethral ostium. According to the tutor, the animal presented the condition since its adoption at 2 months old. The general physical examination did not show any changes in the physiological parameters. The mucous membranes were normal in color, the capillary refill time was 2 s, there was no pain or discomfort on superficial and deep palpation of the abdomen, and the heart and respiratory rates were within the range considered normal for the species. The specific examination found the existence of a fistula on the ventral aspect of the foreskin, whose resolution required a surgical intervention that consisted of obliteration of the fistula communication channel by suturing the defect using an absorbable suture thread. However, this was not effective in solving the problem of the animal, which returned to the hospital complaining of ischuria, leading to the need for 2 other surgical procedures: A scrotal urethrostomy, whose result was also inadequate due to the displacement of the urethral catheter given the postoperative conditions and the animal's temperament, and, to guarantee the proper functioning of the lower urinary tract, avoiding recurrences, a new urethrostomy dorsal to the first, in the perineal region, was performed. The animal did not present episodes of urinary retention after the third procedure and had a significant improvement in the condition in which it was before the initial treatment.

 Discussion: Urogenital anomalies are rare in dogs and can be acquired or congenital. With an etiology still not fully elucidated, the variety of fistula presentations indicates that the condition probably has multifactorial causes. The affection may be confused with hypospadias. However, in this case, the external urethral ostium is out of its anatomical location, and several other abnormalities are present, like cryptorchidism, intersexuality, and penile underdevelopment. The history obtained through the anamnesis, associated with the absence of traumatic episodes in the region and other associated congenital alterations, leads to the understanding that it is a urethral fistula not associated with hypospadias and has a congenital origin. The failure of the first surgical intervention provides relevant data in search of the probable causes of fistula formation. The impossibility of urethral catheterization associated with ischuria consequent to the obliteration of the defect is indicative that the urethral path was blind-ended or with a significant reduction of the lumen, and the resulting increase in pressure can be considered a factor for the formation of the fistula.

Keywords: dog, urological anomaly, urology, surgery.

Título: Fístula uretro-prepucial em cão sem raça definida - Uretrostomia

Descritores: cão, anomalia urogenital, urologia, cirurgia.