Medullary Aplasia in a Patient Treated for Crohn's Disease
Would azathioprine (AZA) account for a severe persistent, medullary aplasia in a young patient treated for anal fistulae with Crohn's disease? AZA was discontinued 2 weeks previously.

Cris Rincon, LMS, FRCA

There are several reported cases in the literature of red cell aplasia in association with AZA. Some of these cases involved concomitant infection with parvovirus. This raises the question of whether the parvovirus infection is the prime or associated factor in conjunction with AZA. Parvovirus is a potentially treatable condition with immunoglobulin infusions.

In any patient with chronic anemia, the antimetabolite therapies, such as AZA, cytoxan, and mycophenolate mofetil, need to be considered in the differential diagnosis. Exclusion of treatable causes of bone marrow suppression or underproduction should be undertaken before consideration of discontinuation of these therapies. In patients on prednisone and a calcineurin inhibitor, it is usually safe to discontinue antimetabolite therapy.