Etiology of hyposiderinemia and anemia in Crohn's disease

Abstract

In a prospective study the frequency of anaemia and serum iron deficiency was investigated in 373 patients with Crohn's disease. Anaemia was present in 52% of patients, hyposiderinaemia in 37%. Involvement of the colon resulted in more pronounced anaemia and hyposiderinaemia than in pure ileitis. For further assessment of iron metabolism serum ferritin or iron binding capacity as well as intestinal iron absorption were determined in 34 patients both anaemic and hyposiderinaemic. In 22 patients sideroachrestic anaemia due to inflammation was found, 5 patients showed iron deficiency due to bleeding. In 6 patients simultaneously lowered serum iron and ferritin or increased latent iron binding capacity with non-increased iron absorption indicated relative iron absorption defects. In one case also the absolute intestinal iron absorption was decreased. However, in only one of these 7 patients typical microscopic changes of Crohn's disease were demonstrable in the upper intestine. 1. Anaemia in Crohn's disease is most frequently caused by inflammation (sideroachrestic anaemia). 2. In colonic involvement the anaemia can be aggravated by iron deficiency due to bleeding. 3. In rare cases part of the anaemia can be due to iron absorption defects which need not necessarily be associated with macroscopic recognizable mucosal damage.