Pneumonia is a breathing (respiratory) condition in which there is an infection of the lung. Pneumonia is a common lung infection caused by bacteria, a virus or fungi. Pneumonia is not a single disease. It can have more than 30 different causes. Understanding the cause of pneumonia is important because pneumonia treatment depends on its cause.
Types of Pneumonia
There are many different kinds of pneumonia, ranging from mild to severe. There are 4 basic types:
- Community-acquired pneumonia (CAP), the most common type of pneumonia, is caused by bacteria, viruses, and other organisms that are acquired outside of the hospital or other health care settings.
- Hospital-acquired pneumonia (HAP) occurs at least 48 hours after someone has been admitted to the hospital. It can be caused by bacteria and other organisms that are usually different from CAP. HAP is usually more serious than CAP because the bacteria and organisms can be harder to treat, and because people who get HAP are already sick.
- Aspiration pneumonia occurs when liquids or other irritants are inhaled into the lungs. The most common type of aspiration pneumonia is caused by inhaling stomach contents after vomiting. People with medical problems (e.g., stroke, ALS) that affect swallowing are at an increased risk of this type of pneumonia.
- Opportunistic pneumonia occurs in people with weakened immune system (e.g., people with AIDS, cancer, organ transplant). Organisms that are not usually harmful to people with healthy immune systems cause these types of infections.
Causes of Pneumonia
There are five main causes of pneumonia:
- Other infectious agents, such as fungi – including pneumocystis
- Various chemicals
Risk factors that increase your chances of getting pneumonia include:
- Chronic lung disease (COPD, bronchiectasis, cystic fibrosis)
- Cigarette smoking
- Dementia, stroke, brain injury, cerebral palsy, or other brain disorders
- Immune system problem (during cancer treatment or due to HIV/AIDS or organ transplant)
- Other serious illnesses, such as heart disease, liver cirrhosis, or diabetes mellitus
- Recent surgery or trauma
- Surgery to treat cancer of the mouth, throat, or neck
Symptoms of Pneumonia
The most common symptoms of pneumonia are:
- Cough (with some pneumonias you may cough up greenish or yellow mucus, or even bloody mucus)
- Fever, which may be mild or high
- Shaking chills
- Shortness of breath, which may only occur when you climb stairs
Additional symptoms include:
- Sharp or stabbing chest pain that gets worse when you breathe deeply or cough
- Excessive sweating and clammy skin
- Loss of appetite, low energy, and fatigue
- Confusion, especially in older people
Diagnosis of Pneumonia
If pneumonia is suspected it is important to seek medical attention promptly so that an accurate diagnosis can be made and appropriate treatment given.
The doctor will take a medical history and will conduct a physical examination. During the examination the doctor will listen to the chest with a stethoscope. Coarse breathing, crackling sounds, wheezing and reduced breath sounds in a particular part of the lungs can indicate pneumonia.
In order to confirm the diagnosis a chest x-ray is usually taken. The x-ray will show the area of the lung affected by the pneumonia.
Blood tests may also be taken and a sample of the sputum may be sent to the laboratory for testing.
Treatment of Pneumonia
Pneumonia is usually treated with antibiotics, even if viral pneumonia is suspected as there may be a degree of bacterial infection as well. The type of antibiotic used and the way it is given will be determined by the severity and cause of the pneumonia.
If able to be treated at home, treatment usually includes:
- Antibiotics – given by mouth as tablets or liquid
- Pain relieving medications
- Paracetamol to reduce fever
If treatment in hospital is required, treatment usually includes:
- Antibiotics given intravenously (via a drip into a vein)
- Oxygen therapy – to ensure the body gets the oxygen it needs
- Intravenous fluids – to correct dehydration or if the person is too unwell to eat or drink
- Physiotherapy – to help clear the sputum from the lungs.