What is peritonitis in dogs?

Peritonitis is an inflammation of the peritoneum — the membrane that lines the inside of a dog’s abdominal cavity. It is a very serious and painful disease which, sadly, is often fatal.

There are two broad types of peritonitis — primary peritonitis which comes on spontaneously without any pre-existing conditions in the abdomen, and secondary peritonitis which occurs as a result of other factors causing the abdomen to become infected. Secondary peritonitis is most common in cats and dogs while primary peritonitis is quite rare.

Secondary peritonitis can be further split into two categories, septic and non-septic, with septic peritonitis being the most common.

I’m worried my dog has peritonitis, what should I do?

Peritonitis is an extremely serious, life-threatening condition which requires immediate, intensive veterinary treatment. If you suspect your dog has peritonitis, contact your vet immediately or, out of hours, your nearest Vets Now pet emergency clinic or 24/7 hospital.

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What causes peritonitis in dogs?

The most common cause of septic peritonitis is infection due to piercing of the gastrointestinal (GI) tract, which includes the stomach, oesophagus, intestine and gallbladder. This is often a result of perforation of a dog’s abdomen when they swallow a foreign body, like a toy. Other causes of peritonitis include abdominal or intestinal surgery complications, pancreatitis and abdominal trauma.

In rare cases, peritonitis may be caused by an infection that has spread from the bloodstream, for example, viruses, parasites, fungi, or bacteria. In some cases, the cause is unknown.

What are the symptoms of peritonitis in dogs?

Peritonitis in dogs symptoms can include weakness, rapid breathing, vomiting, loss of appetite, diarrhoea, decreased defecation, black stools, unwillingness to lie down and showing visible signs of pain, including reluctance to let you touch their abdomen. Sadly, sudden death can also occur due to shock from the large amounts of bacterial toxins.

Other clinical signs, which your vet may be best placed to identify, include fever, blood poisoning, shock, low blood pressure, bleeding, pale gums, jaundice, rapid heart rate, obstruction of the intestines, abdominal swelling, fluid accumulation in the abdomen and abdominal masses.

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How will my vet diagnose peritonitis in dogs?

In order to diagnose peritonitis, your vet will consider your dog’s symptoms and their health history, and ask you about any possible factors that may have caused the issue. If they suspect your dog has peritonitis, they will usually perform a complete physical examination, as well as further tests which could include blood tests, x-rays and abdominal ultrasound. They may also take a sample of abdominal fluid to analyse.

How is peritonitis in dogs treated?

First of all, your vet will typically deal with any consequences of peritonitis, for example, shock, or fluid loss. They will also attempt to identify the cause of the inflammation and eliminate it. They may also give your dog antibiotics and medication to reduce inflammation.

Once your pet has been stabilised, the vet may perform surgery in order to explore the abdomen and fix any problems. They may then thoroughly rinse your dog’s abdominal cavity to remove any irritants.

After surgery, your vet may use drains to make sure that any abnormal fluid can continue to be removed.

Treatment after surgery can include fluids, electrolytes, and antibiotics. Many animals with peritonitis won’t eat after surgery, so they may need to be fed intravenously.

How can I prevent the risk of peritonitis?

Due to the number of different possible causes of peritonitis in dogs, there is no single way to prevent the disease. However, as an injury due to foreign body ingestion is one of the main causes of peritonitis in dogs, keeping unsuitable items well out of your dog’s reach is absolutely vital.