Practice Scenario

Duffy, a male Bernese Mountain Dog

Meet DUFFY

A 2-year-old, neutered male Bernese Mountain Dog

  • Duffy is presented today for intermittent chronic small bowel diarrhea. Although the owner reports he only defecates 2 to 3 times per day and has no urgency, he does have voluminous soft stools. The owner also reports the diarrhea and flatulence have occurred consistently over the past 6 months. What the owner finds concerning today is Duffy’s lethargy, which started 2 days ago.
  • Duffy currently eats a high-protein dry dog food formulated for all life stages that is purchased at a pet specialty store. The owner reports that the dog’s appetite has been good. Year-round, Duffy is given once-monthly medication to protect against heartworm disease, ticks, fleas, roundworms, and hookworms.
  • Physical exam findings are unremarkable. However, a comparison of Duffy’s weight today with previous body weights in the medical record reveals he has lost weight. His body condition score today is 4/9, compared to 5/9 at previous visits.
  • Blood, urine, and fecal samples are obtained and submitted to a reference laboratory for overnight evaluation. No evidence of intestinal parasites or ova are observed. However, the results of the serum chemistry profile reveal a mild panhypoproteinemia.

Gastrointestinal Disorders

Protein-Losing Enteropathy in Dogs

Protein-losing enteropathy (PLE) is a syndrome characterized by excessive loss of plasma proteins, particularly albumin, into the gastrointestinal (GI) tract.1 Most often, protein loss reflects conditions in the small intestine that interfere with digestion and/or absorption of nutrients, such as increased mucosal permeability, lymphatic obstruction or rupture, and mucosal ulceration or erosion.2 In adult dogs, the major diseases associated with PLE include primary GI disorders, such as intestinal lymphangiectasia, severe chronic enteropathy and intestinal lymphoma,1,3 although any GI disease can lead to intestinal protein loss if it is severe enough.3,4 

Dogs with PLE typically have a severe negative protein and energy balance that makes nutritional support essential.1 Diet modification is one component of an aggressive, multimodal approach to the therapeutic management of dogs with protein-losing enteropathy.

canine intestines icon

Key Messages

  • Dietary fat should be restricted (< 4 g/100 kcal metabolizable energy [ME]) for dogs with PLE, regardless of the underlying cause. 
    • Most fats in dog foods consist of long-chain triglycerides (LCTs), which are packaged into chylomicrons inside enterocytes and then transported via the lymphatic system to the thoracic duct where they enter the general circulation.6  
    • LCT absorption increases lymph flow and protein content,7 which can contribute to lymphatic congestion, mucosal damage and protein loss, and worsen clinical signs.8 
    • Limiting dietary fat intake decreases lymph flow, reduces lymphatic vessel distention, and minimizes protein losses.8 
  • Dogs with PLE can be cachectic.8 Since low-fat diets are lower in calories, dogs experiencing severe weight loss may benefit from a diet containing C8 and C10 medium-chain fatty acids (MCFAs) as an alternative energy source.5,8  
    • Medium-chain triglycerides (MCTs) can replace some, but not all, long-chain triglycerides in the diet. Linoleic acid, alpha-linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are all long-chain fatty acids that are considered essential for dogs. 
    • MCTs are quickly and easily digested in the small intestinal lumen without stimulating cholecystokinin secretion or relying on pancreatic lipase and bile acids for absorption.5,8 
    • Most of the MCFAs are absorbed rapidly and transported via the portal vein directly to the liver.6,8 A small amount of MCFAs can be incorporated into chylomicrons and transported via the lymphatic system, but this is dramatically less than with LCTs.9 
  • When lymphangiectasia (which is covered in more detail separately) is the underlying cause of protein-losing enteropathy, a highly digestible, low- or very-low-fat diet (< 4 g/100 kcal ME and < 2 g/100 kcal ME, respectively) that provides enough protein and calories is usually recommended to prevent further lacteal dilation and rupture and to remove a source of intestinal inflammation (i.e., lymph leakage). 
  • When PLE is associated with chronic enteropathy (which is also covered in more detail separately), a highly digestible hydrolyzed or novel protein diet that also is low in fat and highly palatable should be considered to reduce diet-related inflammation, support protein synthesis in the liver, and replace lost tissue proteins.1 
    • In severe or nonresponsive cases, an amino acid-based, or elemental, diet can provide readily available amino acids and small peptides for protein synthesis.1 
    • Low serum cobalamin (vitamin B12) concentrations can occur in concurrent PLE-chronic enteropathy cases, negatively affecting metabolism and delaying healing of intestinal inflammation.9 Parenteral cobalamin supplementation may be necessary. 
  • Supplementation with fat-soluble vitamins (i.e., A, D, E, and K) may be needed due to chronically impaired fat absorption or when dietary fat content is low. 
  • Dogs with PLE initially should be fed small meals 3 to 4 times per day to increase food intake and improve nutrient absorption. 
  • In severe cases, partial or total parenteral nutrition may be needed to facilitate recovery. 
conversation starter

“An important part of your dog’s treatment will be a special diet, one that is low in fat and with highly digestible carbohydrate and hydrolyzed or novel protein. This new food will be the only food your dog should eat, and you will need to use the food as treats, too. [Dog’s name] will need to be fed small, frequent meals initiallyꟷ3 to 4 meals a dayꟷto help improve absorption of nutrients and help control diarrhea.”

Related Tools and Content:

Intestinal Lymphangiectasia in Dogs

Restricting dietary fat is a critical nutritional modification in the management of dogs with lymphangiectasia.

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Chronic Enteropathy in Dogs

Nutrition can play an important role in diagnosis and management of dogs with chronic enteropathy.

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How to Perform a Body Condition Assessment - Dog

Assess a dog's Body Condition Score in just 3 simple steps.​

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Use Muscle Condition Scoring to Detect Muscle Loss in Patients

Muscle condition scoring is a hands-on method for evaluating lean body mass that can be used as part of nutritional assessments.

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To Share With Pet Owner:

Purina Fecal Scoring Chart

The Purina Fecal Scoring Chart is a practical, easy-to-use tool that can help clients describe their pets’ stools.

View Tool 1 min to 5 min

Evaluating Your Dog’s Body Condition

Assess your dog's Body Condition in just 3 simple steps.​

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References

  1. Dossin, O., & Lavoué, R. (2011). Protein-losing enteropathies in dogs. Veterinary Clinics of North America: Small Animal Practice, 41(2), 399─418. doi: 10.1016/j.cvsm.2011.02.002 
  2. Ridyard, A. (2020). Small intestine: Chronic disease. In E. J. Hall, D. A. Williams, & A. Kathrani (Eds.), BSAVA manual of canine and feline gastroenterology (3rd ed., pp. 213─223). British Small Animal Veterinary Association. 
  3. Willard, M. (2015). Canine protein losing enteropathies. Israel Journal of Veterinary Medicine, 70(3), 17─20. 
  4. Peterson, P. B., & Willard, M. D. (2003). Protein-losing enteropathies. Veterinary Clinics of North America: Small Animal Practice, 33(5), 1061─1082. doi: 10.1016/s0195-5616(03)00055-x 
  5. Craven, M. D., & Washabau, R. J. (2019). Comparative pathophysiology and management of protein-losing enteropathy. Journal of Veterinary Internal Medicine, 33(2), 383─402. doi: 10.1111/jvim.15406 
  6. Gross, K. L., Yamka, R. M., Khoo, C., Friesen, K. G., Jewell, D. E., Schoenherr, W. D., Debraekeleer, J., & Zicker, S. C. (2010). Macronutrients. In M. S. Hand, C. D. Thatcher, R. L. Remillard, P. Roudebush, & B. J. Novotny (Eds.), Small animal clinical nutrition (5th ed., pp. 49─105). Mark Morris Institute. 
  7. Simmonds, W. J. (1954). The effect of fluid, electrolyte and food intake on thoracic duct lymph flow in unanaesthetized rats. Australian Journal of Experimental Biology and Medical Science, 32(3), 285─300. 
  8. Davenport, D. J., Jergens, A. E., & Remillard, R. L. (2010). Protein-losing enteropathies. In M. S. Hand, C. D. Thatcher, R. L. Remillard, P. Roudebush, & B. J. Novotny (Eds.), Small animal clinical nutrition (5th ed., pp. 1077─1083). Mark Morris Institute. 
  9. Jensen, G. L., McGarvey, N., Taraszewski, R., Wixson, S. K., Seidner, D. L., Pai, T., Yeh, Y.-Y., Lee, T. W., & DeMichele, S. J. (1994). Lymphatic absorption of enterally fed structured triacylglycerol vs physical mix in a canine model. American Journal of Clinical Nutrition, 60(4), 518─524. 
  10. Gaschen, F. (2013, January 19─23). Approach to chronic diarrhea in dogs: Does protein-losing enteropathy warrant additional concern? [Lecture]. North American Veterinary Conference, Orlando, Florida. https://www.vetfolio.com/learn/article/approach-to-chronic-diarrhea-in-dogs-does-protein-losing-enteropathy-warrant-additional-concern