Inguinal hernia

From Dog

Inguinal hernia are a relatively common congenital or acquired disease of dogs characterized by an opening of the inguinal ring and herniation of abdominal contents into the resultant sac.

Fat and omentum were the most common hernial contents but intestinal and reproductive contents can also evaginate into the hernia[2].

Anatomically, the inguinal canal is both shorter and larger in diameter in females than in males. Hernias of the inguinal region may be unilateral or bilateral and have been divided into two categories, indirect and direct. In an indirect hernia, the abdominal viscera enter the cavity of the vaginal process and, in males, can proceed into the scrotum[3]. In a direct hernia, the abdominal organs pass through the inguinal ring adjacent to the normal evagination of the vaginal process, sometimes resulting in strangulation of intestinal loops[4]. In males, indirect inguinal hernias commonly become scrotal hernias and are usually designated as such[5].

Acquired hernias occur in obese animals (in which the canal is held open by the local accumulation of fat), in older entire bitches (in which the gravid uterus may be herniated), resulting pyometra[6] and following trauma which result in pressure-induced rupture of the inguinal ring. Sex hormones, in particular estrogen, could also be involved in the pathogenesis of inguinal hernia, because the majority of inguinal hernias appear during estrus or pregnancy and have not been reported in neutered females[7].

Prepubic hernia is a traumatic hernia in small animals, most often associated with severe trauma to the caudal abdomen[8].

Clinical signs of herniation are often nonspecific, and the resultant hernia may not be readily apparent during routine physical examination. Inguinal hernias may also be accompanied by traumatic diaphragmatic hernia.

Diagnosis is often based on a thorough physical examination in conjunction with abdominal radiography and abdominal ultrasonography[9].

A differential diagnosis would include inguinal hematoma or lymphoma and cryptorchidism or testicular neoplasia (seminoma, Sertoli cell tumor)[10].

Multiple methods of repair of prepubic hernia (herniorrhaphy) have been reported, and survival rates are quite good if concurrent injuries are not severe[11].

References

  1. Firehouse Chihuahuas
  2. Waters DJ et al (1993) A retrospective study of inguinal hernia in 35 dogs. Vet Surg 22(1):44-49
  3. Fry PD (1991) Unilateral inguinal scrotal hernia in a castrated dog. Vet Rec 128(22):532
  4. Iverson WO (1977) Strangulated inguinal hernia in a Basset hound. Vet Med Small Anim Clin 72(3):408-409
  5. Shahar R et al (1996) A possible association between acquired nontraumatic inguinal and perineal hernia in adult male dogs. Can Vet J 37(10):614-616
  6. Gogny A et al (2010) Pyometra in an inguinal hernia in a bitch. Reprod Domest Anim 45(6):461-464
  7. Smeak DD (1993) Abdominal hernias. In: Slatter D, ed. Textbook of Small Animal Surgery, 2nd ed. vol 1. Philadelphia: WB Saunders. pp433-454
  8. Beittenmiller MR et al (2009) Clinical anatomy and surgical repair of prepubic hernia in dogs and cats. J Am Anim Hosp Assoc 45(6):284-290
  9. Mitchener KL et al (1990) Use of ultrasonographic and nuclear imaging to diagnose scrotal hernia in a dog. J Am Vet Med Assoc 196(11):1834-1835
  10. Hayes HM et al (1985) Canine cryptorchism and subsequent testicular neoplasia: case-control study with epidemiologic update. Teratology 32(1):51-56
  11. Peddie JF (1980) Inguinal hernia repair in the dog. Mod Vet Pract 61(10):859-861