A 28-year-old Nigerian man with known sickle cell anaemia (HbSS) presents with acute severe chest pain, fever (38.9°C), worsening hypoxia (SpO2 88% on room air), and a new bilateral pulmonary infiltrate on CXR. His haematocrit is 18% (baseline 24%). What is the diagnosis and most critical immediate therapeutic intervention?
- A Pneumonia; start antibiotics only and observe
- B Pulmonary embolism; start anticoagulation immediately
- C Acute chest syndrome; exchange transfusion (simple transfusion if unavailable) to reduce HbS percentage to < 30%, alongside oxygen, analgesia, and antibiotics ✓
- D Vaso-occlusive crisis with atelectasis; IV fluids and analgesia only
Correct answer: C. Acute chest syndrome; exchange transfusion (simple transfusion if unavailable) to reduce HbS percentage to < 30%, alongside oxygen, analgesia, and antibiotics
Explanation
Acute chest syndrome (ACS) in SCD — defined as new pulmonary infiltrate plus fever, respiratory symptoms, or oxygen desaturation — is a life-threatening emergency. Exchange transfusion is the definitive treatment that rapidly reduces HbS% to < 30%, alleviating vaso-occlusion in pulmonary vasculature; simple transfusion is used if exchange is unavailable but risks hyperviscosity. Broad-spectrum antibiotics (covering atypical organisms), supplemental oxygen, and incentive spirometry are concurrent measures. ACS is the leading cause of death in SCD adults.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.