A primigravida at 32 weeks with sickle cell disease (HbSS) presents with acute chest syndrome: fever 38.8°C, chest pain, new pulmonary infiltrate on CXR, and SaO2 falling to 91%. Which intervention has BEST evidence for improving outcomes specifically in pregnancy-associated acute chest syndrome?

• A Hydroxyurea 15 mg/kg/day to reduce sickling
• B Simple top-up transfusion to hemoglobin > 10 g/dL
• C IV broad-spectrum antibiotics and supportive care only
• D Exchange transfusion (red cell exchange) to reduce HbS < 30% ✓

Explanation

Exchange transfusion (erythrocytapheresis) to reduce HbS percentage to < 30% is the definitive treatment for severe or rapidly deteriorating acute chest syndrome (ACS) in sickle cell disease, and this standard also applies in pregnancy. It removes the sickled red cells while maintaining normovolemia and avoiding hyperviscosity — unlike simple transfusion which raises overall hemoglobin without reducing HbS fraction. Hydroxyurea is contraindicated in pregnancy due to teratogenicity. Simple transfusion alone for severe ACS is inferior to exchange transfusion. Antibiotics (covering atypical organisms, especially Chlamydia/Mycoplasma) are adjunctive but not sufficient alone for severe ACS.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.