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Inguinal Hernia

Issue Description
An inguinal hernia is a protrusion of an organ or parts of an organ, fat or tissue through the inguinal ring, i.e. the region in the groin where the abdominal musculature meets the back legs. It can be unilateral or bilateral. It is more frequent in females than in males. West Highland White Terriers have an above-average risk for this condition as do Basset Hounds, Cairn Terriers and Pekingese.

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.

Overall inguinal hernias occur less frequently than umbilical hernias and results form a defect in the inguinal ring through which abdominal contents protrude. Inguinal hernias in males are normally direct hernias, whereas those in females can be either indirect or direct.

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.

Dogs with inguinal hernias usually present with a painless mass with a soft doughy consistency. This can occur on one or both sides, although in dogs most cases have only one side affected with the hernia more commonly occurring on the left side.

Careful history taking is helpful in diagnosing inguinal hernias. Where a dog is showing signs of vomiting, belly pain and depression the possibility of intestine being trapped in an inguinal hernia must be considered. Also a prior breeding or vaginal discharge associated with an inguinal mass may indicate involvement. However the history is not of great assistance when only fat protrudes through the inguinal rings.

Diagnosis can be confirmed by reducing a mass in the inguinal region. Where there is a mass in the inguinal area that cannot be reduced the area should be surgically explored as the contents could include abdominal organs, mammary tumour or lymph node just to mention a few. Surgery will identify whether or not this non-reducible mass is actually a hernia.

Where a hernia is detected it should be surgically repaired as soon as possible. Usually surgery is quite successful although patients often are reluctant to walk for several days after surgery presumably because the walking causes stretching and/or inflammation on the repaired area.

In some cases, no treatment is required. Some hernias found in puppies can also wait for repair until they are spayed or neutered.

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 tissue damage.

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