Urethral Hemorrhage

Harold C. Schott II • Alexandra J. Burton

Although a recognized cause of hemospermia in stallions, defects or tears of the proximal urethra at the level of the ischial arch are a more recently described cause of hematuria in geldings.^1-4 Urethral defects typically result in hematuria at the end of urination, in association with urethral contraction.

Examination of affected horses is often unremarkable, and laboratory analysis of blood reveals normal renal function, although mild anemia can be an occasional finding.

FIG. 34.14 Endoscopic image of the proximal urethra of a gelding with hematuria at the end of urination. A urethral defect can be seen between the arrows along the caudal aspect of the urethra as it passes dorsocranially over the pelvic brim.

of the ischial arch. External palpation of the urethra in this area is usually unremarkable but can assist in localizing the lesion, because external digital palpation can be seen through the endoscope. With hematuria of several weeks' duration, there is little evidence of inflammation; rather, the lesion appears as a fistula communicating with the vasculature of the corpus spongiosum penis (Fig. 34.14).

Although the pathophysiology of this condition remains unclear, it has been speculated that the defect is the result of a “blowout” of the corpus spongiosum penis (cavernous vascular tissue surrounding the urethra) into the urethral lumen.³ Contraction of the bulbospongiosus muscle during ejaculation causes a dramatic increase in pressure in the corpus spongiosum penis, which is essentially a closed vascular space during ejaculation. The bulbospongiosus muscle also undergoes a series of contractions to empty the urethra of urine at the end of urination, so the defect into the urethra may develop by a similar mechanism in geldings. Once the lesion has been created, it is maintained by bleeding at the end of each urination, and the surrounding mucosa heals by formation of a fistula into the vascular tissue.

Because hematuria may resolve spontaneously, no treatment may be initially required. Resting of breeding stallions for several months may facilitate healing of the rent and cessation of recurrent bleeding. If hematuria persists for more than a month or if significant anemia develops, surgical intervention is indicated. Surgical approaches are aimed at reducing decreas­ing pressure within the corpus spongiosum, with the goal of reducing tension on the urethral rent site and thus allowing it to heal.³ A temporary subischial “incomplete” urethrotomy has been successful in some affected geldings. After sedation and epidural or local anesthesia, a catheter is placed in the urethra and a vertical incision is made into the corpus spon­giosum penis but not the urethral lumen. The surgical wound requires several weeks to heal, and moderate hemorrhage from the corpus spongiosum penis is apparent for the first few days after surgery. Hematuria should resolve within a week after this procedure. Additional treatment consists of local wound care and prophylactic antibiotic treatment (typically a trimethoprim-sulfonamide combination) for 7 to 10 days. Most recently, a case series (1989 to 2013) of 33 male horses (stallions and geldings) with urethral rents treated with perineal ure­throtomy (PU) or corpus spongiotomy (CS) has been described.⁴ Both PU and CS were successful in the long term for resolving hematuria in horses with urethral rents but did not always resolve hemospermia in stallions.⁴ Repair of a urethral defect using subischial urethrotomy and a buccal mucosal urethroplasty has been described as a successful treatment for recurrent hemospermia in one stallion.⁵