What Is Your Diagnosis?

Theodora C. Dong Department of Veterinary Medicine, College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766.

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Maria A. Fahie Department of Veterinary Medicine, College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766.

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 DVM, MS, DACVS

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History

An 8-week-old 6.6-kg (14.5-lb) sexually intact male mixed-breed shelter dog was evaluated because of an abnormally developed prepuce and atypical urination posture. The dog had been placed in foster care. The fosterer reported the dog had no signs of difficulty urinating, but the urine stream was observed to exit the body ventral to the anus. The dog had a preputial abnormality that the fosterer considered to be cosmetically unacceptable; concern existed that the abnormality may ultimately result in the dog not being adoptable.

Physical examination revealed a urethral opening ventral to the anus but no evidence of licking or skin irritation around this urethral orifice. In addition, the urethral opening was normal in diameter, with a urine stream directed caudally. The external anal sphincter seemed incompletely formed, with the ventral aspect lacking normal rectal mucosa and musculature. Anal sphincter tone was palpably normal, and digital rectal examination did not reveal any abnormalities. Anal glands were detected, but the duct openings were located more dorsally than typical. On the ventral aspect of the abdomen, the penis was exposed because the prepuce failed to encircle the penis. The scrotum was not well developed, but the testes were found in the normal position for an 8-week-old dog. Although the bulbous glandis was present, aplasia of the penile muscles, glans, and potentially the corpus cavernosum and corpus spongiosum was noted.

No abnormalities were detected on serum biochemical analysis, CBC, and urinalysis. The dog was placed under general anesthesia for abdominal radiography (Figure 1); radiographs obtained were limited to lateral views because the dog was hypothermic while anesthetized and it was anticipated that the vertebral column and abdominal contents would obscure visualization of the urinary tract in a ventrodorsal image.

Figure 1—
Figure 1—

Right lateral radiographic view of the abdomen of an 8-week-old mixed-breed shelter dog evaluated because of an abnormal prepuce and atypical urination posture.

Citation: Journal of the American Veterinary Medical Association 241, 8; 10.2460/javma.241.8.1025

Determine whether additional imaging studies are required, or make your diagnosis from Figure 1then turn the page

Diagnostic Imaging Findings and Interpretation

Following evaluation of the lateral survey radiograph of the abdomen, voiding positive-contrast cystourethrography was performed while the dog continued to be anesthetized (Figure 2). Contrast agent was injected into the urinary bladder via catheterization of the urethral opening below the anus. Passage of contrast medium from the urethra through the orifice ventral to the anus, similar to a healed perineal urethrostomy site, was evident. The os penis was not visualized, and no penile urethral opacification was observed. The bladder had a normal shape and was in the correct position. No evidence of bladder rupture or communication between the bladder and adjacent structures was evident. Considering the lack of leakage of positive contrast medium outside of the urethra, other abnormalities (eg, urethral fistula, hernia, and evidence of trauma) were ruled out. Although hypospadias was suspected on the basis of physical examination findings, findings on the positive-contrast cystourethrogram confirmed the diagnosis.

Figure 2—
Figure 2—

Right lateral radiographic views of the same dog as in Figure 1. A—Same radiograph as Figure 1. Notice the region of the preputial skin defect (arrow). B— Voiding positive-contrast cystourethrography was performed with the patient in right lateral recumbency. A wooden spoon compressing the bladder was needed to aid the initiation of urination and to reduce radiation exposure to personnel. Notice the urethral opening (dorsal arrow). Contrast material exits caudally and trickles down the caudal skin folds of the dog when in lateral recumbency (ventral arrows).

Citation: Journal of the American Veterinary Medical Association 241, 8; 10.2460/javma.241.8.1025

Given that a congenital anomaly, hypospadias, was identified in the dog, other related congenital anomalies also considered included pseudohermaphroditism and true hermaphroditism. Abdominal ultrasonography revealed no evidence of ovaries or other female reproductive organs; however, in an 8-week-old dog, these structures would be expected to be small and could have been missed.

Treatment and Outcome

The dog underwent preputial reconstruction and castration at the request of the fosterer. The dog recovered uneventfully from surgery and had no signs of urinary incontinence or periurethral skin irritation when returned 10 days later for suture removal. Two months after surgery, the dog had no dysuria or clinical signs of urinary tract infections. The dog was subsequently adopted and lost to follow-up.

Comments

Apart from confirming hypospadias, the purpose of performing voiding positive-contrast cystourethrography was to validate that the remainder of the urinary tract appeared normal.1 No evidence consistent with other congenital anomalies, such as retrograde ureteral flow or ureteral dilation consistent with ectopic ureters or ureteroceles, were found via voiding positive-contrast cystourethrography. Ureteral dilation might not develop until > 8 weeks of age and may only occur after an ascending urinary tract infection. An IV pyelogram would be needed to definitively rule out ectopic ureters or ureteroceles. In the dog of the present report, voiding positive-contrast cystourethrography also revealed no communication between the urethra and the colon that would have been consistent with a urethral-colonic fistula.

Hypospadias is a developmental anomaly of the male genitalia in dogs.2 The condition results from the failure in fusion of the urogenital folds, causing premature involution of the interstitial cells of the developing testes.3,4 With the cessation of androgen production, incomplete masculinization of the external genitalia3 and incomplete formation of the penile urethra during fetal development occur.4 As a result, the penile urethra, penis, prepuce, or scrotum develops abnormally. The external urethral meatus can be located anywhere on the ventral aspect of the penis to the perineal region.5 Hypospadias is classified on the basis of the location of the urethral opening and may be glandular, penile, scrotal, perineal (as in the dog of the present report), or anal.2,5 Surgical management of patients with hypospadias requires consideration of the individual dog's health and stage of the condition.

  • 1. Burk RL, Feeney DA. The abdomen. In: Small animal radiology and ultrasonography: a diagnostic atlas and text. 3rd ed. St Louis: Saunders Co, 2003;358359.

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  • 2. Jurka P, Galanty M, Zielinska P, et al. Hypospadias in six dogs. Vet Rec 2009; 164:331333.

  • 3. Pavletic MM. Reconstruction of the urethra by use of an inverse tubed bipedicle flap in a dog with hypospadias. J Am Vet Med Assoc 2007; 231:7173.

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  • 4. Galanty M, Jurka P, Zielinska P. Surgical treatment of hypospadias. Techniques and results in six dogs. Pol J Vet Sci 2008; 11:235243.

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  • 5. Hardy RM, Kustiritz MVR. Theriogenology question of the month. J Am Vet Med Assoc 2005; 235:11451146.

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