The differential should include other causes of hemolysis, such as that found in non-immune hemolytic anemia including intrinsic red cell defects, hemolysis due to extrinsic factors (ie trugs or toxins) as well as mechanical damage hemolytic anemia as found in DIC and HUS.
The best initial antibiotic choice is thought to be a macrolide. Macrolides provide the best coverage for the most likely organisms in community-acquired bacterial pneumonia (CAP). Macrolides have effective coverage for gram-positive, Legionella, and Mycoplasma organisms. Azithromycin administered intravenously is an alternative to intravenous erythromycin.
Streptococcus pneumoniae, a type of bacteria, is the most common cause of pneumonia. Legionella pneumophila is the bacterial type that causes the pneumonia known as Legionnaires' disease. Other bacteria types that can cause pneumonia include the bacteria that cause so-called atypical pneumonia, Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumonia. The most common cause of viral pneumonia in adults is the influenza virus. A number of different respiratory viruses cause pneumonia in children, such as respiratory syncytial virus (RSV).