Introduction
Protein-losing enteropathy is characterized by the severe loss of serum proteins into the intestine. Normal protein loss in the gastrointestinal tract mainly consists of sloughed enterocytes and pancreatic and biliary secretions. Albumin loss through the gastrointestinal tract normally accounts for 2-15% of the total body degradation of albumin, but, in patients with severe protein-losing gastrointestinal disorders, the enteric protein loss may reach up to 60% of the total albumin pool.
The serum protein level reflects the balance between protein synthesis, metabolism, and protein loss. Protein-losing enteropathy is characterized by more loss of proteins via the gastrointestinal tract than synthesis leading to hypoalbuminemia. It is not a single disease, but an atypical manifestation of other diseases.
Pathophysiology
The pathophysiology of this disorder is directly related to the excessive leakage of plasma proteins into the lumen of the gastrointestinal tract. Mechanisms for gastrointestinal protein loss include lymphatic obstruction, mucosal disease with erosions, ulcerations, or increased mucosal permeability to proteins as a result of cell damage or death. Proteins entering the gastrointestinal tract are metabolized into constituent amino acids by gastric, pancreatic, and small intestinal enzymes and are reabsorbed. When the rate of gastrointestinal protein loss exceeds the body's capacity to synthesize new proteins, hypoproteinemia develops.
Frequency in United States
The prevalence rate is not known.
International Frequency
The prevalence rate is not known.
Mortality/Morbidity
Morbidity and mortality of this condition directly relate to its cause, either primary gastrointestinal disease or a multisystem disorder.
No racial, sex, age and Clinical predilection exists.
History
- The most common presenting symptom is swelling of the legs or other areas due to peripheral edema secondary to decreased plasma oncotic pressure, with subsequent transudation of fluid from the capillary bed to the subcutaneous tissue.
- If the protein-losing gastroenteropathy is related to other systemic diseases (eg, congestive heart failure, constrictive pericarditis, connective-tissue disease, amyloidosis, protein dyscrasias), the clinical presentation may be that of the primary disease process.
- Patients with primary gastrointestinal disease present with diarrhea with or without bleeding, abdominal pain, and/or weight loss.
- Along with a loss of proteins, a significant loss of immunoglobulins and lymphocytes can also occur. This may lead to the development of an immunological deficiency, predisposing to infections.
Physical
- Physical examination reveals peripheral edema and, in rare cases, anasarca.
- Evidence of the underlying medical problem (eg, cardiac disease, amyloidosis) may exist.
- If a primary gastrointestinal etiology exists, the abdominal examination findings may be unremarkable. Hepatosplenomegaly may be present, depending on the underlying process.
Causes
Primary gastrointestinal mucosal diseases (typically ulcerative/erosive) include the following:
- Erosions or ulcerations of the esophagus, stomach, or duodenum
- Regional enteritis
- Graft versus host disease
- Pseudomembranous colitis (Clostridium difficile)
- Mucosal-based neoplasia
- Carcinoid syndrome
- Idiopathic ulcerative jejunoileitis
- Amyloidosis
- Kaposi sarcoma
- Protein dyscrasia
- Ulcerative colitis
- Neurofibromatosis
- Cytomegalovirus infection
Increased interstitial pressure or lymphatic obstruction leading to protein loss can be caused by the following:
- Tuberculosis
- Sarcoidosis
- Retroperitoneal fibrosis
- Lymphoma
- Intestinal endometriosis
- Lymphoenteric fistula
- Whipple disease
- Cardiac disease (constrictive pericarditis or congestive heart failure)
- Intestinal lymphangiectasia
Nonerosive upper gastrointestinal diseases include the following:
- Cutaneous burns
- Whipple disease
- Connective tissue disorders
- Acquired immunodeficiency syndrome (AIDS)
- Enteropathy, such as angioedema (idiopathic or hereditary) and Henoch-Schönlein purpura
- Celiac sprue
- Tropical sprue
- Allergic gastroenteritis
- Eosinophilic gastroenteritis
- Giant hypertrophic gastritis (Ménétrier disease)
- Bacterial overgrowth
- Intestinal parasites
- Microscopic colitis
- Dientamoeba fragilis
