Intestinal Protein Loss in Dogs

Animals absorb essential nutrients such as protein through their intestines, especially the small intestine. The small intestine is creased and folded with projections called villi that increase the available surface area for absorption. A healthy animal should be able to absorb most or all of the useful components of their food. Sometimes, a food allergy or anything causing inflammation of the gut can flatten these villi and/or impair the complete absorption of nutrition. This can cause vomiting, diarrhea, and electrolyte imbalance. Contact and schedule an appointment with a veterinarian immediately if you notice your dog has vomited, passed irregularly soft stool, or seems to be losing weight. Intestinal disorders often come on very gradually, and treating them before they become more severe is the best course of action.

• Weight loss
• Weakness
• Bloated uncomfortable abdomen (fluid in the abdomen)
• Difficult breathing (fluid in the chest) (Heart problem)
• Decrease in muscle mass
• Chronic diarrhea
• Vomiting
• Tremors and abnormal behavior (resulting from low blood calcium)
• Excessive urination
• Uncharacteristic lack of energy
• Fluid buildup in tissues (edema) - you will notice this in your dog's legs and feet

• Food allergy
• Infection in the intestines, this can arise in many shapes and forms including:
• Salmonella - Bacterial
• Fungal
• Viral (Parvo)
• Inflammatory bowel disease (IBD)
• Parasitic infection - hookworms, whipworms
• Ulcers in the stomach or intestines
• Lymphangiectasia
• Pulmonary thromboembolism (rare)
• Intestinal Neoplasia - lymphoma, adenocarcinoma
• Congestive herat failure

Take your pet to the veterinarian’s office for any gastrointestinal upset that does not resolve by the next meal given. Be prepared to give a detailed medical history of your pet, including any medications, recent surgeries or dietary changes. If you make your pet’s food at home, yourself, or are attempting to feed your dog a vegetarian diet, share this with the veterinarian as well. In all likelihood, the veterinarian will request a stool sample for gastrointestinal complaints, so it can speed up the diagnosis to collect one prior to visiting the veterinarian.

The veterinarian’s main goal will be to differentiate protein-losing enteropathy (PLE) from numerous other conditions that present with similar symptoms. Many times, PLE presents as a symptom of a broader gastrointestinal ailment. First, a physical examination of your dog may reveal loss of muscle mass and fluid accumulation in body cavities (abdomen/chest). The veterinarian will feel for abnormalities in your dog’s abdomen. Blood tests will show if the blood protein (albumin and globulin) is low, as well as if the calcium and cholesterol is low. An analysis of the dog’s urine can rule out protein-losing kidney disease. An ultrasound the abdomen if often recommended. An ultrasound is a helpful noninvasive tool for viewing the inside of the body without bulky or expensive equipment. The veterinarian will be able to spot bowel inflammation and identify if any abnormalities can be biopsied with an endoscope. An endoscope is a long, flexible tube with surgical instruments and/or a camera on the end. This can be used to take a tissue sample for examination in the lab. Sometimes a laparotomy (abdominal exploratory) is required to get full thickness biopsies of the intestine and biopsies of the lymph nodes to get a diagnosis.

Examination of the pet’s stool can determine whether small or large intestine-based diarrhea is occurring, and the presence of parasites. Small intestine-based diarrhea can indicate PLE. Blood tests can rule out infection or implicate parasites, and an analysis of the dog’s urine can rule out protein-losing kidney disease.

Another helpful clue can be low calcium, a side effect of PLE, and causes tremors, abnormal behavior, and elevated heart rate. Finally, administering an IV radiotracer of 51CrCl3 can identify PLE by measuring how long it takes the radioactive marker (which binds to protein) to be excreted.

PLE is best managed by treating the underlying condition if any. Parasitic infections are treated with antiparasitic drugs, IBD with immune system suppressants, surgery and/or chemotherapy for cancer of the bowel, antibiotics for intestinal infections, appropriate medications for congestive heart failure, low-fat diet for lymphangectasia, and in the rare event of a pulmonary thromboembolism, removal of the clot and administration of blood thinners. Idiopathic PLE (not arising from any identifiable cause) is treated in two ways, the first of which is supplementing the animal’s diet with high-quality, easily digestible foods rich in protein and unsaturated fatty acids. Second, an elimination diet can be given to see if a food allergen or component of the animal’s diet is irritating the bowel. This involves systematically replacing certain food items with others and monitoring the animal’s response for improvement.

If an underlying cause is not found, idiopathic PLE is a lifelong but manageable condition. Proper supplementation of the dog’s diet with formulas approved by the veterinarian is often successful in providing your pet with a good quality of life, as long as irritating or hard-to-digest foods are avoided. Follow-up appointments should be made every few months to monitor nutrition uptake, weight gain, and blood chemistry (albumin and globulin). Test different exercise schedules for your dog. You may need to adjust the length, time, and difficulty of common walking routes. If your dog is undergoing a new prescription or medication for treatment, be sure to allow your dog a personal space to rest. It's critically important to give your dog time and space to heal away from distractions, especially other pets.