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Protein-losing enteropathy (PLE) refers to the loss of serum proteins through the mucosal lining into the lumen of the intestine. PLE may result from disruption of the mucosal surface by inflammation or erosion, rupture of lacteals from high pressure in the thoracic duct, or other damage to the mucosal surface that disrupts the mucosal barrier.
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CLINICAL MANIFESTATIONS
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Conditions associated with PLE are listed in Table 385-1 and are discussed in other chapters. Bowel inflammation can result in PLE with hypoalbuminemia; this may be noted in 50% to 60% of children with Crohn disease and 25% of children with gastrointestinal graft-versus-host disease. Intestinal lymphangiectasia presents with intestinal loss of immunoglobulins and lymphocytes, as well as steatorrhea from fat malabsorption. The intestine may be the only site of lymphatic obstruction, or it may coexist with multifocal lymphatic dysplasia (eg, Noonan syndrome). Cardiac disorders or surgical procedures, including clinically silent constrictive pericarditis and the Fontan procedure, in which elevated right atrial pressure is transmitted to the superior vena cava and thoracic duct can cause intestinal lymphangiectasia and PLE. In addition, patients with Fontan-associated PLE have extensive quantitative immune abnormalities. Ménétrier disease is characterized by hypoalbuminemia due to protein losses from hypertrophic gastric folds (see Chapter 404) and can be associated with cytomegalovirus infection. Uncommon entities in which PLE is prominent include the carbohydrate-deficient glycoprotein syndrome 1b and congenital heparan sulfate deficiency. Intestinal lymphangiectasia has been found in intestinal biopsy specimens of some children with idiopathic nephritic syndrome and PLE.
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Other causes of hypoalbuminemia, such as renal disease, liver disease, and malnutrition, should be excluded by urinalysis and liver function studies. A reliable estimate of hepatic synthetic function is provided by the prothrombin time. Vitamin K deficiency resulting from intestinal malabsorption can lead to an abnormal result, but this should correct promptly after a parenteral dose of vitamin K.
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The differential diagnosis for PLE is extensive. Symptoms of the underlying illness, including diarrhea, abdominal pain, and allergic phenomena, may be elicited in the history. Weight-for-age, height-for-age, and weight-for-height can assess for malnutrition as a cause of hypoalbuminemia. Edema is a frequent finding, and asymmetric lymphedema may suggest an underlying malformation of lymphatic channels such as in primary ...