Protein-losing gastroenteropathies are characterized by an excessive loss of serum proteins into the gastrointestinal tract, resulting in hypoproteinemia (detected as hypoalbuminemia), edema, and, in some cases, pleural and pericardial effusions. The diagnosis of protein-losing gastroenteropathy should be considered in patients with hypoproteinemia in whom other causes, such as malnutrition, heavy proteinuria, and impaired protein synthesis due to liver diseases have been excluded.
The normal gastrointestinal tract does not contribute significantly to the catabolism of plasma proteins, accounting for only about 10 percent of the normal turnover of albumin and gamma globulin [1]. Once plasma proteins pass into the gastrointestinal tract, they are degraded rapidly to amino acids and reabsorbed into the portal circulation.
Protein-losing gastroenteropathies can be caused by a diverse group of disorders (table 1). The increase in intestinal leakage of plasma proteins occurs via one of two mechanisms: