Causes: Inguinal hernias may be genetic and present at birth (congenital) or they may be acquired and are often associated with trauma. The mode of inheritance has not been determined specifically but it is thought that many genes are involved in their transmission. In unspayed, middle-aged bitches, it may be caused by stretching of the abdominal muscles during pregnancy or atrophy of the abdominal wall due to old age.  Scrotal hernias are a specific type of inguinal hernia in males. 

Symptoms: Inguinal hernias appear as skin-covered bulges in the groin area. There may be no symptoms, especially when the hernia is reducible, i.e. can be pushed back into the abdomen. When the  bulge cannot be pushed back in the abdomen,  the hernia is said to be incarcerated.  When the blood supply is impaired as when an incarcerated hernia becomes strangulated, the clinical signs change drastically.  The area becomes swollen and painful.  Without treatment,  tissue dies, the affected area turns into an abscess  and there is severe pain, fever, lethargy and the animal refuses to eat or drink. 

Diagnosis: Diagnosis is made by physical exam, palpation and sometimes by Xrays of the abdomen.

Treatment:  In some cases, no treatment is required.  Some hernias found in puppies can also wait for repair until they are spayed or neutered. When surgery is needed,  each of the herniated structures is put back in its correct place and the abnormal opening is sutured shut. 

Prognosis:  Inguinal hernias are usually present before 12 weeks of age. Many will shrink and disappear as the puppy grows, but they have to be watched carefully to make sure no tissue is trapped in the hernial sac. Recovery after surgery is excellent in the presence of a reducible or incarcerated hernia. If the hernia becomes strangulated, liver, intestinal and/or kidney failures may follow and without treatment, the animal will usually die within 24 to 48 hours. When surgery is done in such an emergency, the results depends on the general condition of the animal when it is brought for surgery and on the importance of tissu dammage.

Prevention:  Since this disorder is mostly inherited, dogs that have had hernia or a surgical repair of hernia should not be used for breeding.  In addition, adults who produce puppies with this condition should be removed from breeding programs. 
 

Further reading:

Ackerman L. Keeping your West Highland White Terrier Healthy.  Project TEACH Course Notes for Westie Breeders. Version 1.05  Pet Health Initiative, 1996.

Iverson WO.  Strangulated Inguinal Hernia in a Basset Hound.  Vet Med Small Anim Clin.  1977 Mar;72(3):408-9.

Peddie JE.  Inguinal Hernia Repair in the Dog.  Mod Vet Pract.  1980 Oct;61(10):859-61.

Waters DJ, Roy RG, Stone EA.  A Retrospective Study of Inguinal Hernia in 35 Dogs.  Vet Surg.  1993 Jan-Feb;22(1):44-9.

West Highland Anomaly Task Council, Inc. (Watch). Understanding and Reducing Genetic Disease in West Highland White Terriers, 2nd ed., 1991.
 

Useful links:

http://www.peteducation.com:80/article.cfm?cls=2&cat=1571&articleid=442   Overview of all types of hernia in dogs with their consequences, symptoms and treatment. 

http://www.westieclubamerica.com/health/cmo.html
 

Author: Monique Courtois
Gailuron Kennel
Revised by Dr Yves Gosselin, D.M.V.