<unk>  is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.<unk>  is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms. Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and physical examination. Chest X-rays, blood tests, and culture of the sputum may help confirm the diagnosis. The disease may be classified by where it was acquired, such as community- or hospital-acquired or healthcare-associated<unk> . Risk factors for<unk>  include cystic fibrosis, chronic obstructive pulmonary disease (COPD), sickle cell disease, asthma, diabetes, heart failure, a history of smoking, a poor ability to cough (such as following a stroke), and a weak immune system. Vaccines to prevent certain types of<unk>  (such as those caused by Streptococcus<unk> e bacteria, linked to influenza, or linked to COVID-19) are available. Other methods of prevention include hand washing to prevent infection, not smoking, and social distancing. Treatment depends on the underlying cause.<unk>  believed to be due to bacteria is treated with antibiotics. If the<unk>  is severe, the affected person is generally hospitalized. Oxygen therapy may be used if oxygen levels are low. Each year,<unk>  affects about 450 million people globally (7% of the population) and results in about 4 million deaths. With the introduction of antibiotics and vaccines in the 20th century, survival has greatly improved. Nevertheless,<unk>  remains a leading cause of death in developing countries, and also among the very old, the very young, and the chronically ill.<unk>  often shortens the period of suffering among those already close to death and has thus been called "the old man's friend". script)
Pneumonia
Chronic obstructive pulmonary disease
Aspiration pneumonia
Pulmonary embolism
Bacterial pneumonia
Pulmonary edema
Dust pneumonia
Asthma