Two cases are presented of sickle cell anemia demonstrating evidence of folic acid deficiency during a period of anemic crisis.
One patient had acute hypoplastic crisis associated with megaloblastic erythropoiesis not in conjunction with acute infection, dietary inadequacy, gastrointestinal malabsorption or chronic alcoholism. An increased excretion of urinary formiminoglutamic acid of 8.8 µM/hr. after histidine stimulation was observed in association with more severe anemia than had been noted previously during nine years observation. Prompt reticulocytosis and rise in hematocrit to previous levels occurred when 1 mg. oral daily folic acid was administered. Improvement was accompanied by a fall in FIGlu excretion to normalcy. Since the observation of folic acid responsiveness in this patient, it has not been necessary to transfuse him for a period in excess of 15 months whereas his previous average requirement approached one unit each month for the past seven and one-half years.
A second patient demonstrated increased formiminoglutamicaciduria coincident with anemic sickle cell crisis following bilateral bronchopneumonia with pulmonary thrombosis. There was a beneficial hematologic response to oral folic acid supplementation in physiologic doses. Previously determined control urinary FIGlu levels had been within normal limits.
Increased urinary FIGlu has been observed in five additional sickle cell patients not in anemic crisis. One of these (V. K.) was tested for sensitivity to higher dosage levels of folic acid (5 mg. each day) without improvement.
Low levels of FIGlu-like material persisted in some patients with sickle cell anemia after treatment with folic acid. Indirect evidence would indicate that this material is urocanic acid and may be related to the chronic liver dysfunction frequently present in sickle cell disease.
Evidence has been presented which indicates that folic acid may be a limiting factor in the development of and recovery from anemic sickle cell crisis.