Cardiac disease Cyanotic congenital heart disease. Other causes of right-to-left shunting. Bacterial endocarditis. Gastrointestinal disease Ulcerative colitis.
congenital heart disease gastrointestinal tract and liver inflammatory bowel disease gastrointestinal lymphoma Whipple disease celiac disease primary biliary cirrhosis idiopathic
Secondary forms are associated with pulmonary (cystic fibrosis, pulmonary fibrosis, cancer, chronic infection), cardiac (cyanotic congenital heart disease, patent ductus arteriosus