A hernia in veterinary medicine is best defined as a defect in a structure that defines the borders of a body cavity. This defect in a "wall" of the body may or may not lead to the partial or complete spilling out of the contents of one area into the other. Hernias may be caused by trauma, infections, tumors and other problems, but most commonly occur congenitally. In other words, the animals were born with the defect.
The most common congenital hernias we see in pets occur in the body wall defined by the abdominal muscles. Most tend to occur in areas where there are natural openings within the wall, places where structures passed through during normal development. The umbilicus and "inguinal rings" (where the umbilical cord and testicles pass through, respectively) are the sites most likely to suffer these congenital hernias, though inguinal hernias are much less prevalent.
As the term "congenital" implies, this defect is usually considered a trait passed on genetically from parents to offspring, though trauma during or immediately after birth (while the umbilical cord is still attached) may result in some umbilical hernias. Cats, dogs and, indeed, most mammals are potentially at risk for this condition, though in veterinary medicine we see it most commonly in dogs.
Symptoms and Identification
Most umbilical and inguinal hernias are easily identified by palpating the area and noting a break in the body wall at these two areas (at the belly button for umbilical hernias and on one or both sides of the groin). Sometimes a soft protuberance is palpable and/or visible in these areas.
Though the vast majority of hernias are considered benign, the possibility that important structures may "herniate" through these openings in the body wall (intestines are the most likely to do this) mean that more severe cases are sometimes identified. Intestines and other organs caught up in the opening may actually strangulate and die, leading to emergency conditions.
All breeds of dogs are much more susceptible than cats. In dogs, inguinal hernias are more common in:
In dogs, umbilical hernias are more common in:
In felines, these hernias have been reported more often in Cornish Rex cats.
Treatment for most pets with umbilical or inguinal hernias is surgical. This is typically considered a minor procedure in which the opening is sealed with suture material after replacing any tissue that has slipped through the defect in the body wall.
Some veterinarians do not recommend surgical treatment if the opening is minuscule, but most will due to the possibility that the defect will enlarge with excess weight, trauma, pregnancy and whelping or exercise.
Because enlarged hernias may lead to strangulation and death of involved tissues, these hernias require emergency attention. The possibility of infection and resection of dead tissues can mean many days in the hospital and even death.
Personally speaking, I would never recommend that an owner risk the possibility of severe consequences considering these hernias are so simple to treat when addressed early.
The cost of hernia repair can be quite minor, especially if the procedure is performed at the time of neutering or spaying. In these cases, the anesthetic costs are reduced when two procedures are performed at the same time.
For most minor hernia repairs, including anesthetics (excluding any necessary pre-surgical labwork) pet owners should expect to pay $150-$400.
In case of emergency surgery for a previously undetected or untreated and now complicated hernia (as with the strangulation of important body structures such as the intestines), the cost of surgical repair can be sizable. $500 is common for less complicated situations. But for severe infections, owners have been known to have to spend many thousands of dollars to save their pets.
Prevention of umbilical and inguinal hernias is currently considered best achieved by spaying and neutering affected animals. This is seldom strongly recommended, however, considering the relatively minor impact of this trait on an animal's health--that is, if the hernia is surgically repaired at an early age.
In Cocker spaniels and dachshunds, however, inguinal hernias have been most closely linked to specific genetic changes. That's why animals of these breeds who suffer inguinal hernias should never be bred.
For inguinal hernias, intact female dogs are considered predisposed. As obesity and pregnancy are also predisposing factors, pets should be kept lean.
Genetic aspects of umbilical hernia incidence in cats and dogs. Robinson R. Vet Rec. 1977 Jan 1;100(1):9-10.PMID: 835209 [PubMed - indexed for MEDLINE]
How to delineate canine and feline hernias radiographically.Bartels JE. Mod Vet Pract. 1972 Feb;53(2):27-33. No abstract available.PMID: 5017469 [PubMed - indexed for MEDLINE]
Umbilical hernia in a cat. Alvarenga J, Hagiwara MK, De Martin BW. Mod Vet Pract. 1975 Apr;56(4):260-1. No abstract available.PMID: 1124072 [PubMed - indexed for MEDLINE]