The term lymphangiectasia describes the obstruction of the lymphatic vessels that transport lymphatic fluid through the dog’s body. It is the most common intestinal disease that causes low protein levels in dogs.
Although most of the time it is a primary intestinal disorder, it is interesting to note that gastrointestinal signs (vomiting, diarrhea) are not present in all cases and that the clinical signs are quite varied. In fact, they vary from mild non-specific intermittent to severe weight loss, emaciation and, in some cases, respiratory difficulty secondary to pleural effusion (accumulation of fluids in the thoracic cavity).
Primary or congenital causes of lymphangiectasia in dogs
- Focal lymphangiectasia (intestinal only)
- Diffuse lymphatic abnormalities
- Chylothorax (collection of high-fat lymphatic fluid in the thoracic cavity)
- Lymphedema (swelling of any part of the body due to insufficient lymphatic drainage)
- Chylous ascites (collection of high-fat fluid in the abdominal cavity)
- Thoracic duct obstruction (blockage of the lymphatic system that drains the chest cavity)
Secondary causes of lymphangiectasia in dogs
- Right heart failure
- Constrictive pericarditis
- Budd-Chiari syndrome (blockage of the veins of the liver)
The average age of onset is 5 years. However, this disorder can be observed in older and younger dogs. There appears to be a slightly higher incidence in females than in males.
Although lymphangiectasia can affect all breeds, dogs with a family predisposition include Soft Coated Wheaten Terrier, Basenji, Lundehund and Yorkshire Terrier.
Although some dogs may be asymptomatic (show no clinical signs), others may exhibit potentially lethal manifestations of lymphangiectasia.
Symptoms of lymphangiectasia in dogs can include:
- Weight loss
- He retched
- Ascites (collecting fluid in the abdominal cavity)
- Edema (abnormal accumulation of fluids that can affect any part of the body)
- Respiratory difficulty secondary to pleural effusion (liquid in the thoracic cavity)
What disorders and pathologies to exclude in the early stage of the diagnostic process
The first step in diagnosing lymphangiectasia in dogs is to rule out non-intestinal causes of hypoproteinemia (decrease in the content of total proteins in the blood), specifically related to the liver or kidneys, and therefore exclude other intestinal disorders due to hypoproteinemia.
Many ailments should initially be considered, including:
- Serious liver disease as a contributing cause of hypoproteinemia should be excluded. Examples include: hepatitis (inflammation of the liver), tumor and cirrhosis (end stage of liver disease).
- Protein-dispersing nephropathy (renal disease) should be considered in hypoproteinemic dogs.
- Glomerulonephritis (inflammation of a part of the kidney).
- Amyloidosis – it is the deposition or collection of a type of protein in the organs and tissues that compromises its normal functionality.
- Blood losses, whatever the origin, cause the decrease in the level of proteins as well as causing the onset of anemia.
- Inadequate protein intake or malnutrition can contribute to hypoproteinemia.
- Congestive heart failure can be associated with hypoproteinemia, in particular constrictive pericarditis, a condition in which the tissue that lines the heart is unable to expand for a number of reasons.
- Lymphoplasmic enteritis is a form of inflammatory bowel disease characterized by the infiltration of cells into the intestinal wall, causing an interruption of normal intestinal function and the loss of proteins.
- Intestinal neoplasms (tumors) of any type can cause or contribute to the intestinal loss of proteins. Lymphosarcoma (malignant tumor) is the most common tumor that causes protein loss in the intestine.
- Intussusception (disorder whereby one segment of the intestine slides on another), especially if chronic, can cause protein loss.
- Chronic foreign bodies in the intestinal tract are often associated with a number of gastrointestinal signs (diarrhea, vomiting, weight loss) and occasionally with hypoproteinemia.
- Ulcerative gastroenteritis or disruptions in the lining of the gastrointestinal tract can cause anemia and hypoproteinemia. It can be secondary to inflammation, drug delivery, cancer or foreign bodies.
- Bacterial overgrowth of the small intestine (SIBO) is characterized by an excessive growth of the normal intestinal flora (bacteria) generally secondary to various gastrointestinal pathologies, but occasionally as a primary entity.
- L’histoplasmosis it is a fungal infection that affects many systems, including the gastrointestinal tract. It has been associated with deep hypoproteinemia.
- Intestinal parasitism has been associated with protein-dispersing enteropathy, especially in puppies that also suffer from anemia.
- The food allergy and gluten enteropathy (sensitivity to a component of wheat and other cereals) have been associated with hypoproteinemia.
To diagnose lymphangiectasia in the dog and to rule out other pathological processes that can cause similar symptoms, certain diagnostic tests should be performed.
Complete anamnesis, description of clinical signs and thorough physical examination they are all important for diagnostic purposes. In addition, the following tests are recommended to confirm a diagnosis:
- Complete blood count test. Outcomes may reveal values within normal limits, but often reveal a decrease in lymphocyte count.
- Biochemical profile. Useful for assessing the state of kidneys, liver, proteins and electrolytes. Hypoproteinemia is the hallmark of this disease. Hypocalcaemia (low calcium levels) can often be observed secondary to low protein levels. In addition, hypocholesterolemia (decrease in cholesterol) is common.
- Urine analysis. Often the outcome reveals values within normal limits. It is useful to rule out protein loss associated with kidney disease. If protein loss is suspected to be related to the kidneys, the urine protein-creatinine ratio should be evaluated.
- Stool tests. Useful to exclude the presence of parasitism.
- Thoracic and abdominal radiographs. Although outcomes are often within normal limits, radiographic studies can reveal the presence of fluid in the thoracic or abdominal cavity. They can be useful to rule out other ailments.
- Abdominal ultrasound. It can be indicated if the previous diagnostics has not been conclusive. Although it cannot document the presence of lymphangiectasia, abdominal ultrasound can contribute to a better assessment of the size, shape and integrity of the abdominal organs and is particularly useful in the evaluation of intussusception or pancreatitis.
- Series of radiographic studies of the upper gastrointestinal tract with contrast medium (barium). They can help rule out the presence of foreign bodies and other causes of intestinal obstruction. They are also useful for the evaluation of intestinal ulcers and the thickness of the intestinal wall.
- The evaluation of a portion of the stomach and small intestine is often indicated by gastroduodenoscopy. Biopsies can be collected without an abdominal incision and subjected to microscopic evaluation. Endoscopic biopsies are often diagnostic in cases of lymphangiectasia. General anesthesia is required, although endoscopy is considered a relatively low risk procedure.
To ensure optimal medical care for the dog, the vet may request additional tests that are selected on a case-by-case basis. These can include:
- L’bile acid examination it should be performed in patients in whom hypoproteinemia is potentially secondary to liver disease. These are blood tests obtained before and after a meal in order to evaluate liver function.
- Exams for the evaluation of folate and cobalamin. These are blood tests in which generally the values of folate and cobalamin increase and decrease respectively, in cases with intestinal bacterial overgrowth (SIBO).
- Cytological examination of feces and rectal tissue. It can reveal the presence of histoplasmosis.
- Cardiac ultrasound. It can be performed in those patients in whom heart disease is believed to play a role in hypoproteinemia.
- Laparotomy (abdominal surgery). This procedure allows you to obtain a surgical biopsy of the intestines, lymph nodes and other organs. Laparotomy can be the election exam for the confirmation of lymphangiectasia, in consideration of a characteristic aspect of the intestine and surrounding tissues, as well as the fact that the collection of a large “full thickness” biopsy may be necessary. There are moderate risks associated with surgery on animals with hypoproteinemia and must be performed only if absolutely necessary.
The appropriate therapy for dogs with lymphangiectasia varies according to the type of signs and the severity of the clinical disease.
Depending on the severity of the clinical signs and / or the stage of the disease, hospitalization of the animal may or may not be recommended. Dogs with severe vomiting and / or diarrhea, or hypoproteinemia and associated inappropriate accumulation of fluids, are hospitalized for aggressive treatment and stabilization.
Stable patients can be treated on an outpatient basis as long as they are carefully monitored to verify response to therapy. It is imperative that all the veterinarian’s recommendations are followed and that questions or concerns that may arise during the treatment protocol are addressed immediately.
- There management of the diet it is an important part of therapy for lymphangiectasia. We recommend low-fat diets. In addition, theMCT oil (medium chain triglycerides) is a source of calories well tolerated by patients with lymphangiectasia and in the case of emaciation since it helps to compensate for the missing calories in low-fat diets.
- The use of diuretics to facilitate the removal of excess fluid from the body, it can be indicated in those patients with lymphangiectasia in which the accumulation of fluids in body cavities or tissues can cause clinical problems. Diuretics should be used with caution and only as directed.
- The oncotic agents (plasma, dextran, etetarch) contribute to maintaining the normal distribution of fluids in the body and can be used in patients who need immediate stabilization.
- THE corticosteroids (anti-inflammatory drugs) can be beneficial in these patients.
Other treatment options including surgical procedures may be indicated in patients suffering from secondary lymphangiectasia. For example, pericardectomy (removal of the lining of the heart) may be recommended in patients suffering from constrictive pericarditis.
Optimal treatment requires a combination of home and professional veterinary care. Follow-up can be essential, especially if your dog does not improve quickly.
Make sure to administer all the medications prescribed by your vet as directed. Do not hesitate to contact your veterinarian if you experience problems following the therapy.
Keep your dog’s general activity level, body weight, appetite and possible reappearance of clinical signs (pleural effusion, ascites, edema) monitored. Repeat tests of serum protein levels may be recommended.
- Brett Andrew Grossman, edited by Dr. William Wigle, ADDL Pathologist – Purdue University – Canine Lymphangiectasia ( https://www.addl.purdue.edu/Newsletters/2012/Fall/Canine.aspx )
- Dr. Bari Spielman – PetPlace – Lymphangiectasia in Dogs ( https://www.petplace.com/article/dogs/pet-health/lymphangiectasia-in-dogs/ )