The acute chest syndrome of sickle cell disease.

The acute chest syndrome (ACS), characterized by fever, chest pain, leukocytosis and a new infiltrate on chest roentgenogram, is a common complication of sickle hemoglobinopathies. The major differential diagnoses of ACS are pneumonia and pulmonary vaso-occlusive disease, which may occur simultaneously. Bacterial pulmonary infections are documented infrequently in ACS with the exception being in the pediatric population under 5 years of age. Because there are no clinical or laboratory parameters that clearly allow for distinction between pneumonia and vaso-occlusive disease, empiric use of antibiotics directed against S. pneumoniae and other pathogens commonly seen in community-acquired pneumonias remain a mainstay of therapy.