ABSTRACT: Vomitinq and diarrhoea are two very common presentations in veterinary practice. They may occur together, as seen in gastroenteritis, or may exist independently. It should be remembered, however, that both are clinical signs and not diagnoses. They may be caused by underlying disease or a mechanical abnormality, which may or may not be gastric or intestinal in origin. Both can be caused by a vast number of conditions.

Whilst it is the responsibility of the veterinary surgeon to diagnose the underlying condition and prescribe appropriate treatment, an initial ‘consultation’ often will take place over the telephone. The veterinary nurse will be expected to glean further information on the history, give advice for management of mild cases that may resolve by themselves, in addition to recognising – from the history – when a patient should be brought to the clinic for further examination.

‘Telephone triage’

A current case record for the pet should be accessed – where it exists – and briefly scanned to determine the signalment (description of age, sex and breed) of the patient. This should then be checked with the owner, as records are not always accurate in these respects. Initial information should also be captured on  the status of the pet’s vaccinations and this, together with the signalment, may give some clues.

For example, a young Labrador retriever or bull terrier with vomiting may be more likely to have eaten a foreign body, than an older pet. A young, unvaccinated pup with bloody diarrhoea may have a greater chance of having infectious diarrhoea, such as parvovirus. Vomiting in a middle-aged or older, un-neutered bitch soon after her season, may be symptomatic of pyometra. A domestic long-haired cat, fond of grooming, may have a trichobezoar (hardened hairball) (Figures 1 and 2).

Figures 1 and 2: Hairballs or trichobezoars can come in all shapes and sizes. This example was removed from a cat’s stomach. Images courtesy of Andrea Harvey, University of Bristol.

Further information should then be sought from the owner.

Vomiting : questions to ask

In cases of vomiting, the following should be ascertained:

   Duration and frequency – Is the vomiting recent and acute, or chronic and intermittent? Is it becoming more frequent? How many times a day is the patient vomiting?

   Any other associated signs – Diarrhoea, loss of weight, change in appetite, postural changes (which may indicate abdominal pain)?

   Past history – Has the pet eaten anything unusual, including rubbish? When was it last wormed? Does the pet have a history of gastric or intestinal problems (keeping in mind pancreatitis)? Is there any possibility of trauma?

   Dietary history – What does the pet eat and have there been any changes?

   Medication history – Is the pet currently on non-steroidal anti-inflammatory medication, or any other sort of drug (which can be associated with vomiting)?

The timing of the vomiting in relation to eating may also give clues. Vomiting soon after eating may indicate acute gastritis or a dietary indiscretion; a few hours after eating could indicate a gastric obstruction or intestinal disease. Blood in the vomit (haematemesis) could indicate gastric ulceration or a bleeding disorder; and vomit with a faecal or putrid odour could indicate intestinal obstruction, stasis or ischaemic intestinal disease (where the blood supply to the gut is compromised leading to its death).


Information should be collated and, if in doubt, advice from a vet will help to determine if a consultation is needed.

Gastritis (inflammation of the stomach) is one of the most common causes of vomiting in dogs and cats and is often mild and self-limiting. For patients with suspected acute mild gastritis – for example, from eating rubbish – telephone advice on management can be given, with the proviso that, should the condition not resolve, then it must be seen without delay. For most acute vomiting cases of this type and less than 48 hours in duration, withholding food for 24 to 48 hours generally leads to resolution, with reintroduction of food as soon as the vomiting settles.

For cats, any withdrawal of food should be monitored closely and not allowed to continue too long. Water should be withheld only if not tolerated.

Highly digestible food of a bland nature, for example chicken and rice, can then be introduced in small frequent meals over the following two or three days, along with water, after 24 hours. Specially formulated diets with additional nutrients to support gut health are available and clients can be invited to visit the clinic to collect these (Figure 3).

Figure 3: Diets for gastrointestinal disorders should be highly digestible, low in fibre, hypoallergenic, gluten-free and moderate to low in fat. Image courtesy of Hill’s Pet Nutrition

In general, patients suspected of having any disease other than mild gastritis of a short duration, should be booked in for a consultation. Any patient with very frequent vomiting (more than 5 to 6 times a day) and lasting more than two days, should also be seen for further examination. The practice should always offer an appointment if the client is worried and would prefer it.

Immediate appointments should be made for any animal presenting with nonproductive vomiting or any evidence of gastric distension (which may indicate the life-threatening condition gastric dilatation-volvulus (GDV) – although distension may not be obvious in all cases; any animal with blood in its vomitus (either fresh bright red or black digested blood, indicating possible ulceration); or any animal with a rapid change in its demeanour (weakness or collapse) or symptoms indicating abdominal pain (for example, an ‘acute abdomen’ can be a symptom of many conditions, including acute pancreatitis).


When vomiting is combined with diarrhoea it is known as gastroenteritis (GE). Gastroenteritis is an inflammation of the stomach and the intestinal tract and may also be accompanied by anorexia. The causes are many, including bacteria, viruses, toxins and parasites. It is always better to check these animals at an earlier stage as they will have more risk of becoming dehydrated through fluid loss.

Haemorrhagic gastroenteritis (HGE) yields a bloody diarrhoea and is often accompanied by depression or lethargy, in addition to the previous signs. It is often acute in onset and requires prompt treatment with fluids, as even when dehydration is not apparent clinically, hypovolaemic shock can follow if the patient is not treated with intravenous fluids. The cause of HGE is unknown, but an abnormal response to bacteria or bacterial toxins may be involved.

Treatment of both GE and HGE involves fluid and electrolyte replacement (parentally with HGE) and symptomatic treatment which may include antibiotics. Fluid replacement is usually with
lactated Ringer’s solution to provide bicarbonate to counter any acidosis associated with the diarrhoea. Supplementation with potassium chloride may be needed depending on the severity of the vomiting.


Enteritis, which is an inflammation of the intestine, often results in diarrhoea. Diarrhoea can originate in either the small intestine or the large bowel (colon and rectum), or as a consequence of dysfunction of related structures such as the exocrine pancreas. It can have many causes, can be either acute or chronic, and may be secondary to systemic disease. For example, cardiac disease and renal disease may both be accompanied by diarrhoea. Hyperthyroidism in cats will often lead to bowel problems.

Most cases of diarrhoea are acute and self-limiting and initial advice over the telephone may be to simply withhold food for 24 to 48 hours, with the reintroduction of food, again, as early as possible for cats. Then, as before, a bland easily digestible diet can be introduced, feeding small frequent meals.

Because of the theory that animals can be at an increased risk of developing food allergies during periods of gut compromise, such as diarrhoea, it may be prudent to look carefully at the protein content of any diet given at this time. Some propose that a novel or ‘sacrificial’ protein is used to minimise the risk of a food allergy developing to more commonly available protein ingredients.

The protein chosen should be one that is unusual and won’t be found regularly in any pet food that is fed to the pet in future. That way, if an allergy develops to this unusual ‘sacrificed’ protein, it’s not so critical. Typical novel protein diets may be used which combine this approach with highly digestible ingredients.

Patients with diarrhoea which has lasted more than three days, those whose demeanour is affected, or those who have failed to respond to this simple management should be offered an appointment straight away. Diarrhoea is considered chronic if it has lasted three weeks or more.

Diarrhoea: questions to ask

The following information will be useful to collect from the owner prior to the appointment being made and helps to differentiate between small and large bowel diarrhoea. This information will also be helpful if you need to seek advice from a vet on the urgency of the appointment:

   What is the consistency of the faeces? (Liquid/soft)?

   Are the faeces shiny or greasy? (Fatty faeces, known as steatorrhoea, may indicate small intestinal or pancreatic disease)

   Is there any blood evident, or mucus? (Digested black blood indicates a blood loss or ulceration in the small intestine, which has subsequently been digested. Fresh, bright red blood can be a sign of large bowel inflammation such as colitis, where the blood does not undergo digestion. This may be accompanied by mucus, which will also indicate large intestinal disease. Bloody, smelly diarrhoea can be a sign of HGE or viral gastroenteritis, such as parvovirus infection, and these patients should be isolated on admission.)

   How many times a day is the pet defaecating? (An increased frequency may indicate large bowel disease, such as colitis.)

   How much faeces is there each time? (Small intestinal diarrhoea will usually produce voluminous faeces and large intestinal diarrhoea, a more normal amount.) Acute diarrhoea related to the small intestine is usually osmotic and particles of food in the gut lumen pull in water to produce large voluminous faeces.

   Is there any straining (tenesmus)? (It may again be a sign of large bowel disease).

   Has there been any weight loss? This may indicate small bowel disease or pancreatic disease (Figure 4).

Figure 4: Diarrhoea with weight loss can be a sign of small intestinal or pancreatic disease. (Image courtesy of Hill’s Pet Nutrition.)

   Has the gut been noisy (borborygmi) or has the pet been passing wind (flatulence)? Both signs may indicate small intestinal dysfunction.

   What is his demeanour? (A young dog with diarrhoea, who is depressed, should be checked quickly to rule out the possibility of intussusception – the situation where the bowel telescopes in on itself, leading to devitalisation of the gut wall.)

Again the signalment should be sought and checked against records. Younger animals will be more predisposed towards bacterial or parasitic disease and older animals towards metabolic or neoplastic disease.

Certain breed types may be predisposed towards particular diseases, for example, Boxers are predisposed to ulcerative colitis.

Dietary management

Many cases of vomiting and diarrhoea will respond to simple symptomatic treatment. Water and electrolyte replacement should be considered and the hydration status of any patient with vomiting and diarrhoea should be monitored. Replacement fluids will be indicated for those with evidence of – or at risk of – dehydration. Dietary management should be considered early and often a bland, highly digestible diet will allow the gut to recover. In mild cases, oral electrolyte fluid replacement may suffice, but parenteral therapy may be necessary, particularly in those presenting with vomiting.

Dietary management should also be considered early and often a bland highly digestible diet will allow the gut to recover. Further dietary manipulation – for example the use of hypoallergenic diets (indicated for food allergy or inflammatory bowel disease) or high fibre diets (often used for colitis or constipation) – will depend on the specific type of gut disease diagnosed.

Water and electrolyte replacement should not be ignored and the hydration status of any patient with vomiting and diarrhoea should be monitored. Replacement fluids will be indicated for those with evidence of – or at risk from – dehydration. In mild cases, oral electrolyte fluid replacement may suffice, but parenteral therapy may be necessary, particularly in those presenting with vomiting.

For diarrhoea, clay-based pastes are now also available to help coat the intestinal mucosa and adsorb toxins, which may help to ameliorate signs.


Vomiting and diarrhoea are common presentations in veterinary practice. Many cases can be resolved simply by resting the gut, followed by simple dietary manipulation. However, continuous or more pronounced clinical signs indicate the need for further investigation. The veterinary nurse, whilst not responsible for the diagnosis of the underlying cause, should, nonetheless, have an understanding of the more common reasons for both clinical signs and help to guide owners towards seeking further investigation when necessary.

Further reading

SCHOEMAN, J. P. (2008) Approach to the vomiting patient. Scientific Proceedings WSAVA Congress 2008. pp 424-426.

SIMPSON, K. W. (2008) Chronic small bowel diarrhoea: A diagnostic approach. Scientific Proceedings WSAVA Congress 2008. pp 433-435. CANNON, M. J. and FORSTER-VAN HIJFTE, M. A. (2006) Feline Medicine. A practical guide v
eterinary nurses and technicians. pp 133-139 HALL, E. J. (2009) Canine diarrhoea: a rational approach to diagnostic and therapeutic dilemmas. In Practice 31: 8-16.

GAJANAYAKE, I. and CHAN, D. L. (2009) Nutritional support for the critical care patient. In Practice 31: 386-389.


Libby Sheridan


Libby graduated from Dublin Vet School and spent a number of years working primarily in small animal practice. She then joined the pet food industry before setting up her own business, Mojo Consultancy, offering specialist project management and communication support to the vet and pet care industry. Libby lives in Hertfordshire and is the proud owner of an 11-year-old mongrel, called Gulliver.

• VOL 25 • No4 • April 2010 • Veterinary Nursing Journal