Definition

Peritonitis is an inflammatory process
within the abdomen that involves the
peritoneum and can be localized or
generalized. Localized peritonitis can
occur following surgery, trauma or mild
pancreatitis and usually responds to
medical therapy.

Generalized peritonitis is very serious
and potentially life threatening and is
due to inflammation that overwhelms
the body's normal responses. Fluid
accumulates within the abdomen and
eventually dehydration, weakness and
metabolic abnormalities occur. Some
animals may progress to septic shock.
The dehydration often results from a
lack of available body fluid. These
losses are associated with vomiting,
diarrhea, pooling of abdominal fluid and
fever. Generalized peritonitis can occur
following gastrointestinal surgery,
penetrating injury and severe
pancreatitis. Generalized peritonitis
requires aggressive medical and often
surgical therapy.
Causes

There are a variety of causes of peritonitis, and
it can be primary or secondary. Primary
peritonitis is uncommon and is caused by a
direct infection of the peritoneum. Feline
infectious peritonitis is the only significant
cause of primary peritonitis in dogs and cats.

Secondary peritonitis is more common in
companion animals. Secondary peritonitis is
caused by contamination of the abdomen. Some
causes include ruptured urinary bladder,
ruptured bile ducts or gallbladder, ruptured
tumors or pancreatitis (inflammation of the
pancreas) leading to leakage of pancreatic
enzymes. Other causes include penetrating
abdominal injury, perforated gastrointestinal
ulcers, gastrointestinal foreign bodies, ruptured
infected uterus, ruptured liver or prostatic
abscess, severe pancreatitis and breakdown of
a recent intestinal surgery site.

The most common cause of peritonitis is a loss
of integrity of the bowel. This can occur due to
perforation or dehiscence and is a main cause
of peritonitis.
Diagnosis In-depth

Various diagnostic techniques are used
to diagnose peritonitis. These include:

An abdominal tap. A needle and syringe
are used to obtain a fluid sample. This
sample is then analyzed for the
presence of bacteria and certain cells,
including white blood cells and red
blood cells. The protein level can also
be determined.

Complete blood count. A complete
blood count (CBC) can determine the
number of white blood cells, red blood
cells and platelets. In peritonitis, the
white blood cell count is often
elevated. The red blood cell count may
be elevated if the animal is dehydrated.

Biochemical profile. A biochemical
profile is performed to determine the
function of the body's organs.
Depending on the underlying cause of
the peritonitis, various abnormalities
may be present. The kidney and liver
functions may be abnormal.

The electrolytes, such as sodium,
potassium and chloride may be low due
to excessive vomiting. If the animal has
developed an overwhelming body
infection (sepsis), the blood sugar level
may be low. Pancreatic enzymes, lipase
and amylase, may be elevated if
pancreatitis is present.


Culture. The abdominal fluid can be
cultured to determine the type of
bacteria present and which antibiotics
are most effective.


X-rays. Abdominal X-rays are taken to
determine if there is fluid present in the
abdomen or if there are any tumors,
masses or intestinal blockages.


Abdominal ultrasound can be
performed to help confirm the
presence of fluid and to help determine
the underlying cause of the peritonitis.
Abdominal ultrasound can help detect
liver abscesses, pancreatitis, intestinal
blockage or gall bladder rupture.

Treatment In-depth

Peritonitis can be treated medically or
surgically, depending on the underlying
cause of the peritonitis. If peritonitis is
mild, medical therapy may be sufficient.
Prompt surgery should be performed in
cases of moderate or severe peritonitis
or if the gastrointestinal tract, urinary
bladder or gall bladder is ruptured.

Medical therapy is crucial in correcting
electrolyte abnormalities, controlling
bacterial infections and controlling
pain. Medical therapy includes:


Intravenous fluids or other types of
fluids. If the protein level is low,
hetastarch may be administered.


Antibiotics should be selected based
on culture and sensitivity. While waiting
for the results, a combination of an
aminoglycoside and a penicillin or
cephalosporin can be administered. A
commonly used combination is
gentamicin and cefazolin.


Pain can be treated by using morphine
or similar drugs.

Surgery is recommended in cases of
moderate to severe generalized
peritonitis or if gastrointestinal, urinary
bladder or bile duct rupture is
suspected or confirmed.


Exploratory surgery is often the
treatment of choice. This allows for
exploration of the abdominal cavity to
correct the underlying cause of the
peritonitis. This may involve intestinal
surgery, repair of a ruptured urinary
bladder, abscess or mass removal or
other surgical procedures.

After correction of the underlying
cause, a feeding tube may be placed.

In addition, the abdomen is thoroughly
lavaged with sterile saline solution.

Depending on the severity of
contamination and the ability to remove
all fluid and debris, the abdomen is
either surgically closed or left open. If
left open, the animal is hospitalized and
the abdomen is bandaged. The bandage
is changed often until there is minimal
fluid. The incision is then closed. This
may take several days before the
abdomen can be closed and the animal
sent home.

Follow-up

Antibiotics are often continued for 1 to
2 weeks. Pain control may also be
needed for several days. Additional
follow-up will depend on the underlying
cause of the peritonitis and the animal's
response to therapy.

Animals diagnosed and treated for
peritonitis require close monitoring
immediately after discharge from the
hospital. A complete blood count and
biochemical profile may be repeated
until the values are within normal
ranges.
Overview

The peritoneum is a membrane that lines the abdominal cavity and produces a small
amount of fluid that lubricates the abdominal contents. In addition, the peritoneum is also
responsible for forming adhesions, or scars, in the presence of an inflammatory process.

Peritonitis is an inflammatory process affecting the peritoneum that can be very serious,
or even life-threatening. Peritonitis results in the accumulation of excessive fluid within
the abdominal cavity. It can be associated with abdominal trauma, abdominal surgery or
pancreatitis.

What to Watch For

Vomiting

Diarrhea

Weakness

Fever

Lack of appetite

Abdominal distention

Abdominal pain

Diagnosis

Various diagnostic tests are performed to help determine the presence of peritonitis and
the severity of the infection.

Tests may include:

An abdominal tap to obtain a fluid sample

Complete blood count

Biochemical profile

Culture of the abdominal fluid to determine the type of bacteria

Abdominal X-rays

Abdominal ultrasound

Treatment

Peritonitis can be treated medically or surgically, depending on the underlying cause of
the peritonitis. Medical therapy includes:

Intravenous fluids

Antibiotics

Medication to control pain

Surgery is performed if moderate or severe peritonitis is present. Surgery includes:


Exploratory surgery to address the underlying cause of the peritonitis

Placing a feeding tube

Flushing the abdominal cavity and cleaning with saline
The incision may be closed or left open for a short period of time to allow the remaining
fluid to be removed.

Home Care and Prevention

After treatment, animals are often continued on antibiotics for a period of time. The
animal is monitored for vomiting, lack of appetite or depression.

Peritonitis can be difficult to prevent, but prompt diagnosis and effective treatment of
underlying illness can help reduce the risk.
Peritonitis