Pneumonia

Pneumonia is an important cause of morbidity and mortality globally. It is the leading cause of death in infants and young children with the majority of these deaths occurring in low income countries. Risk factors affecting incidence and outcome include extremes of age, poor nutrition, immunosuppression, environmental exposures and socioeconomic determinants. Pneumonia can be caused by a wide range of pathogens including bacteria, viruses and fungi, and the etiology varies by epidemiological setting, comorbidities and whether the pneumonia is community-acquired or hospital-acquired. Streptococcus pneumoniae is the major cause of community-acquired bacterial pneumonia while Gram negative bacteria, often resistant to multiple antibiotics, are common causes of hospital-acquired pneumonia and pneumonia in immunosuppressed individuals. Diagnosis is generally clinical and management is based mainly on knowledge of likely causative pathogens as well as clinical severity and presence of known risk factors. Timely and effective antibiotic treatment and oxygen therapy if hypoxemic are critical to patient outcomes. Preventive measures range from improved nutrition and hygiene to specific vaccines that target common causes in children and adults such as the pneumococcal or influenza vaccines.