BSc (Hons), RVN, CertCFVHNut, VTS (Nutrition)
Georgia became certified as a veterinary nurse in 2004 from Myerscough College, Preston, United Kingdom. In June 2015, Georgia took the position of Royal Canin Weight Management Clinic Nurse at the University of Liverpool’s Small Animal Teaching Hospital. Her role involves delivering care to patients with obesity and managing specific nutritional requirements of dogs and cats with various disorders. Georgia was awarded a certificate in canine and feline veterinary health nutrition from the College of Companion Animal Studies in 2017, became credentialed as a veterinary technician specialist in nutrition in 2019, and completed a BSc (Hons) veterinary nursing (top-up) degree in 2022.Read Articles Written by Georgia Woods-Lee
Acute gastroenteritis is defined as a sudden-onset digestive disturbance lasting for a short period of time, usually less than 3 weeks. It is one of the top reasons dogs and cats are presented for treatment in small animal practice.1 Diagnosis is made by evaluating clinical signs and excluding other causes; however, gastrointestinal mucosal inflammation is not necessarily present in all cases and, therefore, the term “acute gastroenteropathy” might be more appropriate. Gastrointestinal conditions in which clinical signs are present for more than 3 weeks and may worsen over time are not considered acute.
The most common dietary modification for simple acute gastroenteritis is to feed small amounts of a highly digestible, energy-dense diet several times a day until the clinical signs resolve, at which point the patient can be transitioned to its normal diet over a period of 1 to 2 days. If vomiting is present, withholding food for up to 24 hours might be beneficial, with the exception of in young/growing patients.
Decisions to withhold food (if at all) should be made on a case-by-case basis. Severe or chronic cases of vomiting may require hospitalization and additional support in the form of antiemetics, intravenous fluid therapy, and assisted feeding (e.g., via a feeding tube). Clinical signs indicating that hospitalization is required are listed in BOX 1.
Although the focus of appointments for acute gastroenteritis will mainly be the pet, it is also important to remember that the pet owner will find such problems stressful and upsetting, possibly because their pet is uncharacteristically soiling in the house or if blood is present in either vomit or diarrhea. Therefore, it is important to reassure owners that, as alarming as clinical signs may be, they might not indicate a serious condition unless there are complicating factors.
Causes of Acute Gastroenteritis and Clinical Signs
Although cases of acute gastroenteritis are common, the condition can be challenging to manage, not least because patients often present with a range of clinical signs that might be attributed to different conditions (BOX 2).
Common presenting clinical signs include diarrhea, vomiting, lethargy, dehydration, pyrexia, dysrexia, abdominal pain, and signs of shock. In some cases, blood may be seen in vomit or diarrhea. The presence of blood in feces, along with other characteristics, can help in determining the location of the disturbance in the gastrointestinal tract (TABLE 1).
Medical and Dietary History
At the initial consultation, all components of the signalment should be reviewed, particularly breed, sex, neutered status, and life stage. Patients in growth or senior life stages might be more vulnerable, which might affect the management strategy. For example, causes such as dietary indiscretion and viral infection (e.g., parvovirus enteritis) are more likely in puppies than in adult individuals, with the causes in puppies being life-threatening in some cases.
A nutritional history questionnaire can be helpful in obtaining all relevant nutritional information. The World Small Animal Veterinary Association (WSAVA) Nutritional Assessment Checklist is a useful tool in obtaining this history; it also provides a helpful list of nutritional screening risk factors for the veterinary healthcare team and is free to download at bit.ly/3L2XHK7.
A review of the patient’s clinical history is needed to identify any underlying conditions that might be relevant. In-depth questioning of the presenting clinical signs will also be required. BOX 3 lists questions to guide this part of the history.
Once all relevant information has been obtained, a physical examination should be performed, including the following assessments:
- Body weight
- Body condition score
- Muscle condition score
- Pulse rate
- Respiration rate
- Pain assessment
- Abdominal palpation
- Rectal examination
- Skin tent test to estimate degree of any dehydration
- Mucous membrane assessment for abnormalities such as jaundice
Based on the history and physical assessment, decisions can be made about whether further tests such as blood sampling and diagnostic imaging are required. Clinical findings that would warrant further investigation are listed in BOX 4. For complex cases that require further testing, a suitable treatment plan and dietary recommendation will depend on the results of all tests performed.
Nutrition For Simple Acute Gastroenteritis
Simple cases of acute gastroenteritis have a short history of clinical signs (commonly vomiting, diarrhea, or both). Cases in which further investigations are not warranted based on the clinical presentation often have a dietary cause such as a rapid diet change or dietary indiscretion (e.g., raiding the trash). Such cases benefit from nutritional modification, as do cases in which the cause is unknown.
Rest the Gut or Continue to Feed?
Traditionally, there are 2 options for dietary management: the first is to withhold food for up to approximately 24 hours before reintroducing a “bland diet,” with the rationale being to rest the gut; alternatively, in specific cases, hospitalized patients may be fed despite the clinical signs. Most cases of gastroenteritis are self-limiting and can be managed at home; however, severe or chronic cases with the clinical signs listed in BOX 1 require hospitalization.
Resting the gut might be appropriate for cases with vomiting as a sign (with or without diarrhea), as oral intake of food or water could exacerbate the vomiting frequency, leading to dehydration more quickly. In these cases, withholding food for approximately 24 hours and administering appropriate antiemetic medication and intravenous fluid therapy may be a suitable treatment plan before a gradual reintroduction of food is attempted.
In some rare instances of severe gastroenteritis (e.g., puppies with acute parvovirus enteritis), recovery is improved with hospitalization and nutritional support.3 Further, patients might not benefit overall from withholding food.4 Food should not be withheld for more than 12 hours in puppies and kittens with acute gastroenteritis.5
Dietary adaptation is a crucial part of the management strategy for acute gastroenteritis, both to aid recovery and to prevent recurrence.6 Various therapeutic diets are available for the management of gastroenteritis. Human foods, such as chicken, can be considered initially but, ideally, only to encourage consumption of the selected diet and not as the only food, as they are not nutritionally adequate (TABLE 2).
The following criteria should be considered in choosing a suitable diet:
- Essential nutrient and energy requirements of the individual patient. During recovery from illness, each patient should receive a complete and balanced diet that meets all its essential nutrients and energy requirements. This is especially true for growing animals, given their greater protein and energy needs.
- Energy density of the diet. Feeding an energy-dense food means that energy requirements can be met with a smaller amount of food. This is particularly useful for patients with partial anorexia. Energy should be calculated to meet the resting energy requirement for hospitalized patients and the maintenance energy requirement for patients that remain with their owner.
- Digestibility of the diet. Proteins, fats, and carbohydrates should all be highly digestible to mitigate risks of nutrient malabsorption. Highly digestible diets have also been shown to improve fecal quality.8
- Palatability of the diet. High palatability is needed to encourage food consumption. Palatability is increased in foods containing more fat and protein.
- Fiber content of the diet. Depending on where in the gastrointestinal tract the clinical signs originate (TABLE 1), increased or decreased dietary fiber may not be beneficial. If the disturbance originates in the stomach or small intestine, increased fiber is not recommended. Increased fiber delays gastric emptying and can affect the palatability of the diet. On the other hand, if the disturbance originates in the large intestine, increased fiber is beneficial. In these cases, a blend of fiber should be provided containing both fermentable (to provide nutrition to the colonocytes) and nonfermentable fiber (to add structure to the feces without bulk), which helps normalize fecal transit time and consistency.
Other Nutrient Considerations
For cases of simple acute gastroenteritis, cobalamin deficiency is not an immediate concern; however, should signs persist and become chronic, cobalamin supplementation might be required.9
For patients with chronic gastroenteritis, the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are believed to have anti-inflammatory properties.10 However, there is little evidence that these are beneficial in acute cases, and further work is required to determine their actual biological effects, as well as what cases they most benefit.
It is usually recommended that the selected diet be fed in small amounts, frequently, with meals distributed throughout the day. If the patient is unwilling to eat, warming the food and other tempting techniques such as hand feeding may be required. Once clinical signs have resolved, the patient may be slowly transitioned back to its original diet, typically over 1 to 2 days of dietary adaptation.
The use of probiotics might provide some (albeit limited) benefit in cases of acute gastroenteritis.11 Probiotics are live bacterial organisms that help regulate the normal gastrointestinal microbiome. In acute cases of gastroenteritis, probiotics have been found to shorten the duration of gastrointestinal disturbance and, therefore, may be beneficial alongside dietary adaptation.12 As many probiotic products are available and this product type is not strictly controlled, it is important to communicate to clients that the commercial probiotic they choose should have sufficient quality controls and evidence of efficacy.
Most cases of simple acute gastroenteritis are self-limiting and resolve within the first week. If clinical signs persist, further investigations are required to ascertain the underlying cause.
Acute gastroenteritis is common in dogs and cats and has a wide range of causes. Withholding food is unnecessary in many cases of simple gastrointestinal disturbance, and dietary adaptation may be all that is required to resolve the clinical signs. Suitable diets to feed such patients should provide all essential nutrients and energy, usually in a highly digestible and palatable format. Probiotics may also be of use to help manage the clinical signs. After a few days, when the clinical signs have subsided, the patient should be able to return to its original diet over a short transition period of 1 to 2 days. If clinical signs do not resolve, further investigation is indicated.
1. O’Neill DG, James H, Brodbelt DC, Church DB, Pegram C. Prevalence of commonly diagnosed disorders in UK dogs under primary veterinary care: results and applications. BMC Vet Res. 2021;17(1):1-15. doi:10.1186/s12917-021-02775-3
2. Elwood C, Devauchelle P, Elliott J, et al. Emesis in dogs: a review. J Small Anim Pract. 2010;51(1):4-22. doi:10.1111/j.1748-5827.2009.00820.x
3. Mazzaferro EM. Update on canine parvoviral enteritis. Vet Clin North Am Small Anim Pract. 2020;50(6):1307-1325. doi:10.1016/j.cvsm.2020.07.008
4. Brunetto MA, Gomes MOS, Andre MR, et al. Effects of nutritional support on hospital outcome in dogs and cats. J Vet Emerg Crit Care (San Antonio). 2010;20(2);224-231. doi:10.1111/j.1476-4431.2009.00507.x
5. Qin HL, Su ZD, Gao Q, Lin QT. Early intrajejunal nutrition: bacterial translocation and gut barrier function of severe acute pancreatitis in dogs. Hepatobiliary Pancreat Dis Int. 2002;1(1):150-154.
6. Lenox CE. Nutritional management for dogs and cats with gastrointestinal diseases. Vet Clin North Am Small Anim Pract. 2021;51(3):669-684. doi:10.1016/j.cvsm.2021.01.006
7. Balance.it. Adult dog; chicken breast, skinless, boneless, cooked, roasted. Accessed August 3, 2023. https://balance.it/profile/2470073
8. Nery J, Biourge V, Tournier C, et al. Influence of dietary protein
content and source on fecal quality, electrolyte concentrations, and osmolarity, and digestibility in dogs differing in body size. J Anim Sci. 2010;88(1):159-169. doi:10.2527/jas.2008-1666
9. Volkmann M, Steiner JM, Fosgate GT, Zentek J, Hartmann S, Kohn B. Chronic diarrhea in dogs—retrospective study in 136 cases. J Vet Intern Med. 2017;31(4):1043-1055. doi:10.1111/jvim.14739
10. Calder PC. n-3 Polyunsaturated fatty acids, inflammation, and inflammatory diseases. Am J Clin Nutr. 2006;83(suppl 6):S1505-S1519. doi:10.1093/ajcn/83.6.1505S
11. Jugan MC, Rudinsky AJ, Parker VJ, Gilor C. Use of probiotics in small animal veterinary medicine. JAVMA. 2017;250(5):519-528. doi:10.2460/javma.250.5.519
12. Kelley RL, Minikhiem D, Kiely B, et al. Clinical benefits of probiotic canine-derived Bifidobacterium animalis strain AHC7 in dogs with acute idiopathic diarrhea. Vet Ther. 2009;10(3):121-130.