Pneumonia is a lung infection that causes inflammation in one or both lungs, making it difficult to breathe properly. The infection affects the tiny air sacs in the lungs, known as alveoli, causing them to fill with fluid or pus. As a result, the body receives less oxygen, leading to symptoms such as cough, fever, chest pain, and shortness of breath. Pneumonia can be caused by bacteria, viruses, or fungi, with bacterial pneumonia being one of the most common and serious forms.
The disease can affect people of all ages, but it is particularly dangerous for infants, older adults, pregnant women, and individuals with weakened immune systems or chronic illnesses such as diabetes, asthma, heart disease, or chronic obstructive pulmonary disease (COPD). The severity of pneumonia can range from mild to life-threatening depending on the patient's age, overall health, and the organism causing the infection.
Pneumonia often develops after a cold, flu, or other respiratory infection, although it can also occur independently. The infection spreads through droplets released into the air when an infected person coughs or sneezes. In some cases, bacteria already present in the nose or throat may travel into the lungs and cause infection when the immune system becomes weak.
Doctors diagnose pneumonia using a physical examination, chest X-ray, blood tests, and sputum analysis to determine the underlying cause. Treatment depends on whether the infection is bacterial, viral, or fungal. Most mild cases can be treated at home with medication and rest, while severe cases may require hospitalization, oxygen therapy, or intravenous antibiotics.
With early diagnosis and proper treatment, most people recover completely within a few weeks. However, delaying treatment can lead to serious complications such as respiratory failure, bloodstream infection (sepsis), lung abscess, or fluid accumulation around the lungs. Maintaining good hygiene, receiving recommended vaccinations, and seeking medical care promptly when symptoms appear are essential for reducing the risk of severe pneumonia.
Pneumonia is caused by bacteria, viruses, or fungi that infect the lungs. The most common bacterial cause is Streptococcus pneumoniae, while viruses such as influenza, respiratory syncytial virus (RSV), and COVID-19 can also lead to pneumonia. Fungal pneumonia is less common and usually affects people with weakened immune systems. Risk factors include smoking, chronic lung disease, diabetes, heart disease, weakened immunity, poor nutrition, advanced age, recent respiratory infections, and prolonged hospital stays.
Pneumonia can often be prevented by receiving recommended vaccinations, including the pneumococcal vaccine, influenza vaccine, and COVID-19 vaccine when appropriate. Regular hand washing, avoiding close contact with sick individuals, covering the mouth while coughing or sneezing, quitting smoking, maintaining good nutrition, exercising regularly, and managing chronic medical conditions all help strengthen the immune system and reduce the risk of infection. Seeking early medical care for persistent cough, fever, or breathing difficulties can also prevent pneumonia from becoming severe.