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.
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.
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.
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 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
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.
Treatment 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.
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 tissue damage.