The peritoneal cavity is the inside of the belly (abdomen) that houses vital organs such as the stomach, intestines, spleen, liver, kidneys and bladder. The peritoneum is a very thin membrane that lines the abdominal cavity (peritoneal cavity) and abdominal organs and produces a small amount of fluid that lubricates the abdominal contents. 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 is often associated with acute abdominal pain due to the sudden inflammation of the abdominal tissues, or peritoneum, hence the name for the condition. Peritonitis results in the accumulation of excessive fluid within the abdominal cavity. It can be associated with abdominal trauma, abdominal surgery or pancreatitis and results in severe dehydration and electrolyte imbalance.
This condition can be classified into primary (diffuse) and secondary (localized) cases. Primary peritonitis is when the dog has an infection, disease, ulcers or lesions effecting organs, peritonitis can spread from original site to the peritoneum though the blood vessels. Primary peritonitis usually develops slowly and can take days or even months to show symptoms. Secondary peritonitis develops fast and spreads quickly. It is caused by bacteria, foreign objects, fecal matter and other infectious agents introduced directly through surgery, injury or trauma to the abdominal area.
While young dogs mostly suffer from infecteous and traumatic causes, malignant cancers are more common cause of acute abdomen in older dogs.
Common symptoms associated with peritonitis include
Abnormal posture (i.e., may be "guarding" the stomach by curling up, or leaning forward with back end higher in attempt to relieve pain)
Swollen abdomen (may be rigid to the touch
Diarrhea, which may be black (also referred to as melena)
May have vomiting if the stomach or intestines are involved