Gastroenteritis in Dogs
Gastroenteritis means inflammation of the stomach and intestines. It commonly causes vomiting, diarrhoea or both. Gastroenteritis describes the part of the digestive system affected; it does not identify the underlying cause.
Possible Causes
A sudden digestive upset may follow a change in food or eating something unsuitable. However, vomiting and diarrhoea can also be signs of a more serious problem.
- Eating spoiled food, rubbish or an unfamiliar food
- A sudden dietary change
- Food intolerance
- Parasites
- Viral or bacterial infection
- Swallowing a foreign object
- Toxins or medication
- Pancreatitis
- Liver, kidney or hormonal disease
- Inflammatory or chronic intestinal disease
- Cancer
- Stress
Puppies, unvaccinated dogs and dogs that have recently travelled, mixed with many dogs or eaten raw food may require additional investigation for infectious disease.
Common Signs
- Vomiting or retching
- Diarrhoea
- Nausea, lip licking, drooling or repeated swallowing
- Loss of appetite
- Abdominal discomfort
- Flatulence or a noisy abdomen
- Lethargy or weakness
- Fever
- Dehydration
- Weight loss if the problem continues
A small amount of fresh red blood or mucus can occur with irritation of the large bowel, but any bleeding should be discussed with a vet. Black, sticky or tar-like faeces may contain digested blood and need prompt veterinary assessment.
Vomit resembling coffee grounds may also indicate digested blood. The colour of vomit alone cannot reliably identify its cause.
Contact a Vet Urgently If Your Dog:
- Cannot keep water down or is vomiting repeatedly
- Has a swollen, painful or tense abdomen
- Repeatedly retches without producing vomit
- Has blood in the vomit or a large amount of blood in the diarrhoea
- Passes black, sticky or tar-like faeces
- Appears weak, very sleepy, disorientated or collapses
- Has pale gums or difficulty breathing
- May have swallowed a foreign object, toxin or medication
- Shows signs of dehydration
- Is a young puppy, elderly, pregnant or has another illness
Do not wait for diarrhoea to develop if a dog is repeatedly retching with a swollen abdomen. These can be signs of gastric dilatation and volvulus—bloat—which is an immediate emergency.
Dehydration
Vomiting and diarrhoea cause loss of water and electrolytes. Dehydration can develop quickly, particularly in puppies and small, elderly or already unwell dogs.
Possible signs include:
- Dry or sticky gums
- Sunken eyes
- Weakness or unusual sleepiness
- Reduced urination
- Poor skin elasticity
These checks are not completely reliable at home. A dog that is vomiting repeatedly, refusing water or becoming weak should be examined rather than treated solely with an oral rehydration product.
Diagnosis
The vet will consider the dog's age, vaccination and parasite history, diet, access to rubbish or toxins, travel, medication and the duration and severity of the signs.
Depending on the individual dog, tests may include:
- Physical examination and assessment of hydration
- Blood tests
- Urine tests
- Faecal tests for parasites or infection
- Parvovirus testing
- Abdominal X-rays or ultrasound
- Specific tests for pancreatitis or other disease
- Endoscopy or biopsy in persistent or recurrent cases
Imaging is especially important if an obstruction, swallowed object, abdominal mass or other surgical problem is suspected.
Treatment
Treatment depends on the cause and severity. Restoring fluid and electrolyte balance is often the first priority. Fluids may be given by mouth, beneath the skin or into a vein, depending on the degree of dehydration and whether the dog is continuing to vomit.
Veterinary treatment may include:
- Anti-sickness medication
- Fluid and electrolyte therapy
- Pain relief suitable for the individual dog
- A veterinary gastrointestinal diet
- Probiotics or gut-support products where appropriate
- Specific treatment for parasites or an underlying disease
- Surgery to remove an obstruction or treat another surgical cause
Antibiotics are not needed for every case of gastroenteritis. They are normally reserved for situations where bacterial infection, sepsis or another specific indication is suspected.
Food and Water at Home
Do not routinely withhold all food for 24 hours unless your vet has specifically advised it. Prolonged fasting can be unsuitable for puppies, toy breeds, elderly dogs, diabetic dogs and those with other medical conditions.
If the dog is bright, has stopped vomiting and the vet agrees that home care is appropriate, small frequent portions of an easily digested veterinary gastrointestinal food may be offered. Return to the normal diet gradually as advised.
Fresh water should normally remain available. A dog that gulps large amounts and vomits may need very small, frequent quantities under veterinary guidance. If even small amounts of water cannot be kept down, contact the vet.
Use oral rehydration products only when the vet considers them suitable. They do not replace intravenous fluids in a significantly dehydrated or repeatedly vomiting dog.
Avoid Home Medication
Do not give human anti-diarrhoea, pain-relief or anti-sickness medicines unless a veterinary surgeon has prescribed them for that dog. Some products can be toxic, conceal important signs or be unsuitable where infection or an obstruction is present.
This is particularly important for Collies with the MDR1 mutation, which can cause increased sensitivity to certain medicines, including loperamide.
Helping Your Vet
Make a note of when the signs started, how often the dog has vomited or passed diarrhoea and whether blood or foreign material was seen. Tell the vet about any change in food, possible rubbish eating, missing toys, medication or potential toxin exposure.
A photograph of the vomit or faeces can be helpful. If requested, take a fresh faecal sample in a clean, sealed container.
