Managing Chronic Enteropathies: Beyond Antimicrobials

Chronic enteropathy (or enterocolitis) is characterized by gastrointestinal signs (e.g., inappetence, vomiting, diarrhea, possible weight loss) that persist for longer than 2 to 3 weeks and may represent progression from acute gastrointestinal bouts managed with antimicrobial drugs.^1-4

Chronic enteropathies have been previously classified as food responsive, antimicrobial responsive, and immunosuppressant responsive. These classifications may represent different forms of chronic enteropathy, but they may also overlap or be reflective of a continuum. Additional descriptive terminology includes fiber-responsive and nonresponsive enteropathy.^5-7 Regardless of the form of chronic enteropathy, primary management involves instituting a nutrition plan with an appropriate diet.^8,9

Chronic Enteropathy

Determining an appropriate treatment plan for chronic enteropathy relies on collecting a detailed history of clinical signs and diet, performing a thorough physical examination, and evaluating diagnostic findings. Taking a thorough diet history may reveal dietary indiscretions or feeding of inappropriate or unusual foods, treats, and/or pet supplements; the history may help with selection of a therapeutic diet or a trial of a diet that has not been previously fed. A close review of the medical history may help identify clinical signs that may have lasted longer than 2 to 3 weeks or are recurrent and episodic. Knowing the duration and severity of clinical signs will help determine whether supportive care is appropriate without an extensive workup or whether more intensive care and next-level diagnostic testing are required.

Clinical signs of chronic enteropathy may include episodic bouts of inappetence, picky eating behavior, vomiting, diarrhea, and/or weight loss.⁵ Additional signs may include regurgitation (possibly secondary to esophagitis from recurrent vomiting), flatulence, abdominal pain, hematemesis, tenesmus, hematochezia, melena, and/or constipation.^10,11

Clinical signs will help localize the part of the gastrointestinal tract involved in the disease process (TABLE 1), which aids in identifying key nutrients of concern for diet selection as well as supportive management. Additional diagnostics may include repeating the minimum database (complete blood count, blood chemistry, urinalysis, possibly thyroid testing), imaging (radiography, abdominal ultrasonography), pancreatic enzyme testing (trypsin-like immunoreactivity, pancreatic lipase immunoreactivity), B vitamin status (cobalamin, folate), and adrenocorticotropic hormone (ACTH) stimulation testing. In the authors’ clinical experience, when performing ACTH stimulation testing, it is most thorough and conclusive to add pre- and postaldosterone and even endogenous ACTH testing (go.navc.com/4crCR1x). Also indicated may be tissue biopsies obtained via endoscopy (upper and/or lower gastrointestinal) and/or exploratory surgery or laparoscopy.

Treatment Plans

Antimicrobial Use: Pros and Cons

For dogs experiencing acute or chronic diarrhea, antimicrobial therapy is often prescribed. However, empiric use of antimicrobials for dogs and cats with acute or chronic diarrhea has little scientific support. A recent study noted no improvement in outcomes of dogs receiving antimicrobials versus other supportive supplements.¹² Not only are current studies demonstrating little efficacy of empiric antimicrobial use, but they are detecting deleterious effects of antimicrobials on the gut microbiota. Use of metronidazole and tylosin for acute and chronic diarrhea has been shown to lead to dysbiosis and persistent changes in microbiota richness and composition, which may predispose the patient to frequent relapses after treatment.^13,14 In addition, recent epidemiologic data for humans and dogs with infectious enteritis implicate exposure to antimicrobials as a risk factor for development of inflammatory bowel disease later in life for some patients.^15,16 Clients often expect antimicrobials to be prescribed for their dogs with gastrointestinal signs; therefore, it is important to explain the concerns associated with antimicrobial use (BOX 1).

For some patients, judicious use of antimicrobials may be appropriate. Antimicrobial therapy is recommended for dogs with parvovirus infection and should be considered for those with acute hemorrhagic diarrhea syndrome or immunocompromise (e.g., patients with cancer), all of which may display signs of bacterial translocation with subsequent sepsis (e.g., fever, neutropenia, hypoglycemia).^17,18

As a result of accumulating data, antimicrobial use needs to be reconsidered and replaced by other treatments that do not harm the gut microbiota but rather support and possibly restore its functions. Some strategies are intended to manage clinical signs and address clients’ concerns and frustrations with regard to dealing with clinical signs. Nutritional management, along with client education, can help address these client concerns.

Multimodal Management

Diet Trials

Studies suggest that 50% to 66% or more of patients with chronic enteropathy have food-responsive chronic enteropathy; therefore, diet change or diet trials are diagnostic as well as therapeutic. For patients in stable condition, diet trials can be considered a first-line therapy.^19-21 All noncompliant food or flavored products must be eliminated (if the diet trial contains hydrolyzed or limited ingredients). For patients with food-responsive enteropathy, a strict diet trial may lead to clinical improvement within 2 to 3 weeks.^22,23 For some patients, multiple diet trials may be needed to determine the optimal diet that controls clinical signs. The optimal diet may be a commercial therapeutic diet or a properly formulated and balanced home-prepared diet.

Nutrient Profiles

Reviewing the nutrient profiles (i.e., protein, fat, digestible carbohydrate, and fiber) of the current diet and previous diets that did not resolve signs can help the practitioner select a new diet. In some cases, the commercial diet chosen or the formulated homemade recipe must accommodate more than a single desired feature (e.g., novel protein, fiber enrichment, and/or low fat) and must address the patient’s current life stage (e.g., growth).

Unfortunately, there is no single nutrient profile recommended for all dogs with chronic enteropathy. Rather, diet selection for food trials is based on diet history, clinical signs, and location of bowel affected; the diet can be generally categorized as highly digestible/gastroenteric, high fiber, novel/hydrolyzed protein, and lower fat/ultra-low fat (TABLE 2). An initial trial on a highly digestible diet may be appropriate (BOX 2).

Client Education

In the authors’ clinical experience managing dogs with chronic enteropathies, client education and setting appropriate expectations are paramount for successful management. Clients should be informed that clinical signs probably do not result from pathogenic bacteria and, therefore, instituting a regimen of antimicrobials is not usually indicated. Concerns associated with antimicrobial use should be reiterated. Providing clients with a treatment plan that is safe and prioritizing a “first do no harm” approach may limit signs while also addressing clients’ need to treat.

Before starting a diet trial, clients should be instructed that food trials must be strictly followed and that their pet is not allowed to eat unapproved treats, table foods, or snacks, including foodstuffs used to administer medications, toothpastes, supplements, and chews. Clients should also be informed that several diet trials are often needed before determining that a patient is not food responsive.²⁴ The benefits and limitations of each option (e.g., diet types used in feeding trials; a veterinary therapeutic diet; a balanced, properly formulated home-prepared diet) should also be discussed. Furthermore, clients should be informed that chronic enteropathy patients are often not cured but rather that a “successful outcome” for most patients is reduction in the frequency or severity of clinical signs.

Additional Strategies

A combination of nutritional, supplemental, and medical interventions is used to manage chronic enteropathy. Detailed descriptions and dosing are beyond the scope of this article, but suggestions are listed in TABLES 3 AND 4.

Despite appropriate diet management, clinical gastrointestinal signs may still occur. The authors explain to clients that these recurrences are termed “flares.” Flares require building management plans with specific instructions and including guidelines for when it is necessary for the patient to be seen and treated by the veterinary team. The plan can outline supportive care similar to management of acute enteropathies, including a period of food reduction,^25,26 hydration support, and approved supplements or medications based on clinical signs. A sample plan with some tips for managing flares is provided in this client handout. Successful management of flares involves ensuring that signs remain mild, can be controlled without hospitalization, and are of short duration to avoid progressive damage to the gut and microbiota. If flare episodes are rare and mild, changing the nutrition plan may not be indicated because overall the food plan has reduced the frequency and intensity of clinical signs and improved the patient’s quality of life. For difficult cases, referral to an internal medicine specialist and a veterinary nutritionist may provide the next level of diagnostic testing and expertise for tailoring a specific management plan for patients with chronic enteropathy.

Summary

In general, antimicrobial use for chronic enteropathy needs to be reconsidered and replaced by other supportive interventions that do not harm the gut microbiota. Current management strategies involve client education and nutrition plans supported by supplementation (e.g., absorbents, fiber, probiotics). The best diet for any patient can be determined only by properly performed diet trials. To prevent progressive damage to the gastrointestinal tract and microbiota, proper management of flares needs to be explained to clients.