Hypospadias

From Dog
A dog with hypospadias, showing failure of fusion of the urethra, prepuce, and scrotum resulting in a nonfunctional, caudoventrally deviated and exposed penis with a nonfused prepuce[1]
Hypospadias in a dog, showing the prepuce was missing from the bulbus glandis cranially.[2]

Hypospadias is a common congenital abnormality which results from inadequate fusion of urethral folds[3].

This disease is primarily diagnosed in male dogs (15:1)[4] and in most breeds although Boston Terrier appear to have an underlying genetic predisposition[5].

The underlying etiology may be genetic, but endocrine disrupters such as organochlorines may contribute to organ dysgenesis in utero[6][7].

In affected dogs, the urethral meatus opens on the ventral surface of the penile shaft proximal to its normal location[8].

Penile hypoplasia, ventral deviation and non-functionality may also be observed[9].

Concurrent congenital problems such as cryptorchidism[10], hermaphroditism[11] and pseudohermaphrodism, prostatic absence[12] and renal aplasia have also been reported.

Clinically, these dogs present with urinary incontinence and cystitis, probably due to the close proximity of the urethral meatus to the anus as well as the shorter length of the urethra. Testosterone levels are usually very low and FSH/LH levels often undetectable[13].

Shortening of the penis, amputation or urethral reconstruction are recommended for dogs with recurrent cystitis unresponsive to medical therapy[14]. The surgery is designed to move the urethral stoma to a more cranioventral location away from the anus.

A bilateral orchidectomy is recommended due to the potential heritability of this condition. Excision of the nonfunctional exposed external genitalia to prevent irritation is also advised.

References

  1. Adelsberger ME & Smeak DD (2009) Repair of extensive perineal hypospadias in a Boston terrier using tubularized incised plate urethroplasty. Can Vet J 50(9):937-942
  2. Ndikuwera J (2005) A case of hypospadias in a dog. Ir Vet J 58(9):504-506
  3. Boothe HW (2003) Penis, prepuce, and scrotum. In: Slatter D, editor. Textbook of Small Animal Surgery. 3rd ed. Philadelphia: WB Saunders. pp:1535–1536
  4. Hayes HM & Wilson GP (1986) Hospital incidence of hypospadias in dogs in North America. Vet Rec 118(22):605-607
  5. van der Putte SC (2007) Hypospadias and associated penile anomalies: a histopathological study and a reconstruction of the pathogenesis. J Plast Reconstr Aesthet Surg 60(1):48-60
  6. Sonne C et al (2008) Is there a link between hypospadias and organochlorine exposure in East Greenland sledge dogs (Canis familiaris)? Ecotoxicol Environ Saf 69(3):391-395
  7. Baskin LS (2000) Hypospadias and urethral development. J Urol 163:951–956
  8. Hayes HM & Wilson GP (1986) Hospital incidence of hypospadias in dogs in North America. Vet Rec 118:605–606
  9. Croshaw JE & Brodey RS (1960) Failure of preputial closure in a dog. J Am Vet Med Assoc 136:450–452
  10. Switonski M et al (2012) Hypospadias in a male (78,XY; SRY-positive) dog and sex reversal female (78,XX; SRY-negative) dogs: clinical, histological and genetic studies. Sex Dev 6(1-3):128-134
  11. Jurka P et al (2009) Hypospadias in six dogs. Vet Rec 164(11):331-333
  12. Jurka P et al (2009) Hypospadias in six dogs. Vet Rec 164(11):331-333
  13. Cassata R et al (2008) Clinical, cytogenetic and molecular evaluation in a dog with bilateral cryptorchidism and hypospadias. Cytogenet Genome Res 120(1-2):140-143
  14. Galanty M et al(2008) Surgical treatment of hypospadias. Techniques and results in six dogs. Pol J Vet Sci 11(3):235-243