Life-Threatening Acute Chest Syndrome in a Patient With Sickle Cell Disease After Switching From Hydroxyurea Therapy to Partial Exchange Transfusions: A Case Report

Acute chest syndrome (ACS) is a severe form of vaso-occlusive crisis, which is a main feature of sickle cell disease (SCD), an inherited hemoglobinopathy. Traditionally, hydroxyurea has been the treatment of choice for SCD to prevent vaso-occlusive crises including ACS. However, hydroxyurea may be contraindicated, for example, in patients wanting to have children. We here present a young male with SCD who wanted to become a father and developed a life-threatening episode of ACS following discontinuation of hydroxyurea and switching to partial exchange blood transfusions. The patient, aged 32 years and originally from Bahrain, had been diagnosed with homozygous SCD, alpha-thalassemia, and glucose-6-phosphate dehydrogenase deficiency as a child. He had an episode of ACS with moderate severity in 2008, after which he started using hydroxyurea. From 2008 until the present, he did not experience any episodes of ACS. About six months before the present episode, he stopped using hydroxyurea and switched to partial exchange transfusions, aiming to keep hemoglobin S (HbS) below 30%. The interval between the transfusions was typically about seven to eight weeks. On the evening (day 1) before hospital admission, he developed typical symptoms and signs of vaso-occlusive crisis, and during the first day in the hospital (HbS about 55%), his pulmonary function deteriorated, and he also developed cerebral symptoms (somnolence and confusion). On suspicion of ACS, a full blood exchange transfusion was administered on day 3. He then gradually recovered clinically, and his laboratory values also normalized. He was discharged on day 10. Subsequent follow-up visits at the outpatient clinic the following month were unremarkable. Possibly, this severe episode of ACS was triggered by switching from hydroxyurea therapy to partial exchange transfusions with too long intervals between the transfusions. This novel case is a compelling reminder of the possible perils that may accompany the discontinuation of hydroxyurea, the best-documented therapy in SCD