A 22-year-old Afro-Caribbean man with known sickle cell disease presents with acute onset severe pain in the chest, fever, hypoxia (SpO₂ 89%), and new pulmonary infiltrate on CXR. The MOST urgent specific therapeutic intervention (beyond analgesia, O₂, and IV fluids) is:
- A IV methylprednisolone to reduce vaso-occlusion
- B Hydroxyurea loading dose to rapidly increase HbF
- C Emergency exchange transfusion to reduce HbS percentage to <30% ✓
- D Bronchoscopy with BAL to identify the causative organism before any treatment
Correct answer: C. Emergency exchange transfusion to reduce HbS percentage to <30%
Explanation
Acute chest syndrome (ACS) is a leading cause of death in sickle cell disease, defined by new pulmonary infiltrate + fever/respiratory symptoms. Moderate-to-severe ACS (SpO₂ <90%, multilobar disease) requires emergency exchange transfusion (erythrocytapheresis or manual exchange) targeting HbS <30% and total Hgb of 10 g/dL, rapidly reversing sickling and pulmonary vasoconstriction. Simple transfusion may cause hyperviscosity. Corticosteroids may shorten duration but increase re-admission rates. Hydroxyurea acts over weeks and has no role acutely.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.