Pneumonia is an inflammatory condition of the lung affecting primarily the microscopic air sacs known as alveoli. It is usually caused by infection with viruses or bacteria and less commonly other microorganisms, certain drugs and other conditions such as autoimmune diseases.
Pneumonia is an infection in one or both lung. It can be caused by fungi, bacteria, or viruses. Pneumonia causes inflammation in your lung’s air sacs, or alveoli. The alveoli fill with fluid or pus, making it difficult to breathe.
Pneumonia symptoms can vary from mild to severe, depending on the type of pneumonia you have, your age and health.
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
Symptoms also can vary, depending on whether your pneumonia is bacterial or viral.
- In bacterial pneumonia, your temperature may rise as high as 105 degrees F. This pneumonia causes profuse sweating, and rapidly increased breathing and pulse rate. Lips and nailbeds may have a bluish color due to lack of oxygen in the blood. A patient’s mental state may be confused or delirious.
- The initial symptoms of viral pneumonia are the same as influenza symptoms: fever, a dry cough, headache, muscle pain, and weakness. Within 12 to 36 hours, there is increasing breathlessness; the cough becomes worse and produces a small amount of mucus. There is a high fever and there may be blueness of the lips.