Clinical scenario: Sickle cell disease | pain crisis | tachypnea | infiltrates
A 9-year-old boy with homozygous sickle cell disease (HbSS) is admitted with a vaso-occlusive pain crisis. He has received intravenous fluids, opioids, and incentive spirometry. On the third hospital day, he develops fever, pleuritic chest pain, increasing breathlessness, and oxygen saturation of 88% on room air.
Examination reveals tachypnea and reduced air entry at the right lung base.
Investigations:
- Hemoglobin: 6.7 g/dL (baseline 8.5 g/dL)
- WBC count: 18 × 10⁹/L
- Platelets: 410 × 10⁹/L
- Reticulocyte count: 11%
- Chest radiograph: New right lower lobe infiltrate
Despite oxygen therapy and intravenous ceftriaxone plus azithromycin, his oxygen saturation remains 89–90%, and respiratory distress is worsening.
What is the most appropriate next step in management?
A. Add intravenous methylprednisolone
B. Increase intravenous fluid rate to 1.5 maintenance
C. Perform exchange transfusion
D. Start therapeutic anticoagulation
E. Transfuse one unit of packed red blood cells
Correct answer & Explanation:
Correct Answer: C. Perform exchange transfusion
Explanation:
This child has acute chest syndrome (ACS), the leading cause of death in children with sickle cell disease.
Diagnostic features include:
- New pulmonary infiltrate on chest radiograph
- Fever
- Chest pain
- Hypoxemia
- Respiratory distress
Although simple transfusion is appropriate for mild to moderate ACS, exchange transfusion is indicated in patients with:
- Progressive hypoxemia despite oxygen
- Worsening respiratory distress
- Rapid radiological progression
- Falling hemoglobin with severe disease
- Impending respiratory failure or need for ventilatory support
Exchange transfusion rapidly:
- Reduces the proportion of HbS
- Improves oxygen-carrying capacity
- Decreases blood viscosity
- Improves pulmonary perfusion
Why the other options are incorrect
A. Add intravenous methylprednisolone
- Corticosteroids are not routinely recommended because they may increase the risk of rebound vaso-occlusive pain and rehospitalization.
B. Increase intravenous fluid rate to 1.5 maintenance
- Overhydration may worsen pulmonary edema and respiratory status. Fluids should be carefully managed.
C. Perform exchange transfusion ✅
- The correct management for severe or progressive acute chest syndrome.
D. Start therapeutic anticoagulation
- Pulmonary embolism is not the most likely diagnosis in this scenario.
E. Transfuse one unit of packed red blood cells
- Simple transfusion is appropriate for less severe ACS. Progressive hypoxemia despite optimal medical therapy warrants exchange transfusion.
High-yield pearl
Acute chest syndrome = new pulmonary infiltrate + respiratory symptoms in a patient with sickle cell disease.
Management hierarchy:
- Oxygen
- Broad-spectrum antibiotics (including atypical coverage)
- Adequate analgesia
- Incentive spirometry
- Careful hydration
- Exchange transfusion for severe or worsening disease
This scenario tests the distinction between simple transfusion and exchange transfusion, a classic postgraduate examination concept.
