Pneumonia is an inflammation of the lungs caused by infection. Bacteria, viruses, fungi or parasites can cause pneumonia. The elderly (> 65 years old), very young (Patients who are immunocompromised (eg those with AIDS or cancer) tend to develop pneumonia due to unusual organisms like tuberculosis, fungus or viruses. Viral pneumonia usually occur in situations of epidemics eg SARS and H1N1.Pneumonia can range in seriousness from mild to life-threatening. Symptoms include difficulty in breathing, cough, headache, chest pain, fatigue and fever. A physical examination, history taking, chest x-rays and blood tests can help determine if one has pneumonia.
Treatment will depend on the cause of the pneumonia. If bacteria is suspected, antibiotics will be prescribed. About 50% of patients with pneumonia have an unknown etiology ie the tests to determine the microbiology turn out negative. Treatment of pneumonia usually involves antibiotics. Patients can be managed in the outpatient or inpatient, depending on the level of severity. Antibiotic resistance is becoming a growing challenge, due to the widespread misuse of antibiotics. In patients who are immuno-compromised, the key is to try to identify the offending pathogen, using bronchoscopy or other tests.
The commonest cause of bacterial pneumonia is the Streptococcal Pneumoniae (causing about 40% of all bacterial pneumonias). Pneumococcal vaccination is available and is generally recommended for the very elderly and the young.
Pneumonia is more likely to cause complications in those with weaker immune systems such as the elderly and very young children, as well as smokers and people with heart failure or lung disease such as Chronic Obstructive Lung Disease (COPD).
Pneumonia complications can arise from:
- Bacteria entering the bloodstream (bacteremia)
- Septic shock where normal circulation fails, resulting in end organ failure (eg clotting abnormalities, kidney failure)
- Fluid accumulation and infection around your lungs causing sharp pain, cough and breathing limitations (pleural effusion and empyema)
- Lung abscess (a cavity containing pus)
- Acute respiratory distress syndrome (ARDS). When pneumonia involves most areas of both lungs, breathing is difficult and the gas exchange mechanism fails.