Anemic crises occur during the course of chronic hemolytic anemias, both congenital1-3 and acquired.4-6 These crises, due to temporary cessation of red cell production, are usually related to acute viral infections. Acute erythroblastopenia has also been reported in relation to treatment with various drugs, including chloramphenicol.7-10
The cases reported here are noteworthy for 4 reasons. First, they represent examples of anemic crisis occurring in the course of serious constitutional illnesses in which hemolysis did not seem to be important prior to the appearance of the crisis. Second, all 4 patients studied were receiving chloramphenicol at the time of development of erythroblastopenia. Third, striking "toxic" changes were noted in bone marrow cells at the height of the crisis in all 4 cases; changes of the type to be described have not been emphasized in most previous reports. Finally, in 1 of the 4 cases evidence has been obtained