Key Takeaways

Acute chest syndrome (ACS) is the leading causes of death in patients with sickle cell disease (SCD).

About one-half cases of ACS follow as a complication of vaso-occlusive crisis.

ACS may progress rapidly. Early recognition and treatment are crucial.

Diagnosis is made on the basis of respiratory symptoms and new lung infiltrate(s) on chest X-ray.

Patients with ACS may worsening of anemia and hemolytic markers. They may also have thrombocytopenia.

Treatment includes oxygen, IV fluids, pain relief, incentive spirometry, antibiotics and transfusion.

Red cell transfusion may be simple (“top up”) or exchange, the latter administered manually or as an automated procedure.

Exchange transfusion is indicated in those with severe ACS or those with high baseline Hb. Exchange transfusion not only improves hemoglobin concentration (oxygen delivery) but also reduces HbS (for example, aiming for HbS < 30%).

Whether simple of exchange transfusion, the hemoglobin goal should not be higher than 11 g/dL.

Despite a lower incidence of ACS in HbSC compared to HbSS, severe cases of ACS associated with multiorgan failure and necrotic fat emboli appear more common in HbSC disease. This may be the result of increased blood viscosity due to a higher hemoglobin concentration and packed cell volume.