Lymphangiectasia, also known as "lymphangiectasis", is a pathologic dilation of lymph vessels.McGavin/ Zachary (2007), Pathologic Basis of Veterinary Disease When it occurs in the intestines of dogs, and more rarely humans, it causes a disease known as "intestinal lymphangiectasia". This disease is characterized by

lymphatic vessel The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph ve ...

dilation, chronic

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

and loss of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

s such as

serum albumin Serum albumin, often referred to simply as blood albumin, is an albumin (a type of globular protein) found in vertebrate blood. Human serum albumin is encoded by the ''ALB'' gene. Other mammalian forms, such as bovine serum albumin, are chemica ...

and

globulin The globulins are a family of globular proteins that have higher molecular weights than albumins and are insoluble in pure water but dissolve in dilute salt solutions. Some globulins are produced in the liver, while others are made by the immune ...

. It is considered to be a chronic form of

protein-losing enteropathy Protein losing enteropathy refers to any condition of the gastrointestinal tract (e.g. damage to the gut wall) that results in a net loss of protein from the body. Signs and symptoms The signs/symptoms of protein losing enteropathy are consistent ...

Signs and symptoms

Chronic diarrhea is almost always seen with lymphangiectasia, but most other signs are linked to low

blood protein Blood-proteins, also termed plasma proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, hormones, vitamins and minerals in activity and functioning of the immune system. Other blood pr ...

levels (

hypoproteinemia Hypoproteinemia is a condition where there is an abnormally low level of protein in the blood. There are several causes that all result in edema once serum protein levels fall below a certain threshold. Causes # Nutritional hypoproteinemia is due ...

), which causes low

oncotic pressure Oncotic pressure, or colloid osmotic-pressure, is a form of osmotic pressure induced by the proteins, notably albumin, in a blood vessel's plasma (blood/liquid) that causes a pull on fluid back into the capillary. Participating colloids displace ...

. These signs include

ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, a ...

pleural effusion A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung. Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per k ...

, and edema of the limbs and trunk. Weight loss is seen with long-term disease.

Cause

Biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...

of the small intestine shows dilation of the

lacteal A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine. Triglycerides are emulsified by bile and hydrolyzed by the enzyme lipase, resulting in a mixture of fatty acids, di- and monoglycerides. Thes ...

s of the villi and distension of the

s. Reduced

lymph Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues ...

flow leads to a

malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...

syndrome of the small intestine, especially of

fat In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

and fat-soluble

vitamin A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrie ...

s. Rupture of the lymphatics causes protein loss into the intestines. The most common cause of lymphangiectasia was congenital malformation of the lymphatics. Secondary lymphangiectasia may be caused by granulomas or cancer causing lymphatic obstruction, or increased

central venous pressure Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system. CVP ...

(CVP) causing abnormal lymph drainage. Increased CVP can be caused by pericarditis or right-sided heart failure. Inflammatory bowel disease can also lead to inflammation of the lymphatics and lymphangiectasia through migration of inflammatory cells through the lymphatics.

Diagnosis

Diagnosis is through biopsy. The presence of hypoproteinemia, decreased blood

lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...

s, and decreased

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

support the diagnosis.

Hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mm ...

(low

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

) is also seen due to poor absorption of

vitamin D Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...

and calcium, and secondary to low protein binding of calcium. Medical ultrasonography may show

striation Striations means a series of ridges, furrows or linear marks, and is used in several ways: * Glacial striation * Striation (fatigue), in material * Striation (geology), a ''striation'' as a result of a geological fault * Striation Valley, in Ant ...

s in the

intestinal mucosa The gastrointestinal wall of the gastrointestinal tract is made up of four layers of specialised tissue. From the inner cavity of the gut (the lumen) outwards, these are: # Mucosa # Submucosa # Muscular layer # Serosa or adventitia The muco ...

indicating dilated lacteals. Computerized tomography (CT) can show low attenuation material within the bowel walls which corresponds to lipid-containing chylous fluid within the dilated lymphatic vessels.

Treatment

Treatment is multifactorial. A diet very low in fat and high in high quality protein is essential. By limiting a dog's fat intake, the amount of intestinal lymph that is formed is reduced which also reduces pressure within these faulty ducts. Less pressure means less lymph leakage and a reduction of symptoms. Diets for dogs with lymphangiectasia should not have more than 20% of their calories coming from fat. Treatment of humans can also involve the use of MCT (

medium-chain triglycerides Medium-chain triglycerides (MCTs) are triglycerides with two or three fatty acids having an aliphatic compound, aliphatic tail of 6–12 carbon atoms, i.e. medium-chain fatty acids (MCFAs). Rich food sources for commercial extraction of MCTs inclu ...

) oil and/or the drug

octreotide Octreotide, sold under the brand name Sandostatin among others, is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone. It was ...

. In dogs, fat soluble vitamins ( A, D, E, and K) should be supplemented. Corticosteroid treatment may be required for life. Antibiotics can be used to treat

bacterial overgrowth Small intestinal bacterial overgrowth (SIBO), also termed bacterial overgrowth, or small bowel bacterial overgrowth syndrome (SBBOS), is a disorder of excessive bacterial growth in the small intestine. Unlike the colon (or large bowel), which is r ...

. With a very low

, transfusion with

blood plasma Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intr ...

or an infusion of hetastarch may be necessary to treat the signs until the diet can take effect. Lymphangiectasia is rarely cured but can remain in remission for a long time. It can be fatal when unresponsive to treatment.

In animals

Dog breeds commonly affected by lymphangiectasia and/or protein-losing enteropathy include the Soft-Coated Wheaten Terrier,

Norwegian Lundehund The Norwegian Lundehund (Norwegian: ''Norsk lundehund'') is a small dog breed of the Spitz type that originates from Norway. Its name is a compound noun composed of the elements ''lunde'', meaning puffin (Norwegian ''lunde'', "puffin", or ''lunde ...

Basenji The Basenji ( /bəˈsɛndʒi/) is a breed of hunting dog. It was bred from stock that originated in central Africa. The Fédération Cynologique Internationale places the breed in the Spitz and primitive types. The Basenji produces an unusual y ...

, and

Yorkshire Terrier The Yorkshire Terrier (often shortened as Yorkie) is one of the smallest dog breeds of the terrier type and indeed of any dog breed. The breed developed during the 19th century in Yorkshire, England.Dermal and subcutaneous growths Dog diseases Lymphatic vessel diseases