Pneumonia is an infection in one or both of your lungs. Many germs, such as bacteria, viruses, and fungi, can cause pneumonia. 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.
Approximately one-third of the pneumonia cases in the United States each year are caused by viruses. These viruses are the most common cause of pneumonia in children and young adults.
The flu virus is a common cause of viral pneumonia in adults. Other viruses that cause pneumonia include respiratory syncytial virus (RSV), rhinovirus, herpes simplex virus, severe acute respiratory syndrome (SARS) virus, and more.
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
- Headache
- 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 can cause 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 may be a high fever and there may be blueness of the lips.
Anyone can get pneumonia, but some people are at a higher risk than others.
Risk factors (that increase your chances of getting pneumonia) include:
- Age – younger than 5 and older than 65
- Cigarette smoking
- Recent viral respiratory infection – a cold, laryngitis, influenza, etc.
- Difficulty swallowing (due to stroke, dementia, Parkinson's disease, or other neurological conditions), which can lead to aspiration (breathing in a foreign object)
- Chronic lung disease such as COPD, bronchiectasis, or cystic fibrosis
- Cerebral palsy
- Other serious illnesses, such as heart disease, liver cirrhosis, or diabetes
- Living in a nursing facility
- Impaired consciousness (loss of brain function due to dementia, stroke, or other neurologic conditions)
- Recent surgery or trauma
- Having a weakened immune system due to illness, certain medications, and autoimmune disorders
Many different germs and other things can cause pneumonia. There are five main causes of pneumonia:
- Bacteria
- Viruses
- Mycoplasma
- Other infectious agents, such as fungi—including pneumocystis
- Various chemicals
If you have viral pneumonia, you also are at risk of getting bacterial pneumonia.
There are a few ways that pneumonia is diagnosed:
- Physical exam: Your doctor will listen to your lungs with a stethoscope. If you have pneumonia, your lungs may make crackling, bubbling, and rumbling sounds when you inhale. You also may be wheezing, and it may be hard to hear sounds of breathing in some areas of your chest.
- Chest X-ray (if your doctor suspects pneumonia).
- Some patients may need other tests, including:
- Blood test to check white blood cell count and to try to know the germ which may be in your blood as well.
- Arterial blood gases to see if enough oxygen is getting into your blood from the lungs.
- CT scan of the chest to get a better view of the lungs.
- Sputum tests to look for the organism (that can detect in the mucus collected from you after a deep cough) causing your symptoms.
- Pleural fluid culture if there is fluid in the space surrounding the lungs.
- Pulse oximetry to measure how much oxygen is moving through your bloodstream, done by simply attaching a small clip to your finger for a brief time.
- Bronchoscopy, a procedure used to look into the airways of the lungs, which would be performed if you are hospitalized and antibiotics are not working well.
How is it treated or prevented?
Treatment for pneumonia depends on the type of pneumonia you have and how severe it is, and if you have other chronic diseases. The goals of treatment are to cure the infection and prevent complications.
Most people can be treated at home by following these steps:
- Drink plenty of fluids to help loosen secretions and bring up phlegm.
- Get lots of rest. Have someone else do household chores.
- Do not take cough medicines without first talking to your doctor. Coughing is one way your body works to get rid of an infection. If your cough is preventing you from getting the rest you need, ask your doctor about steps you can take to get relief.
- Control your fever with aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen or naproxen), or acetaminophen. DO NOT give aspirin to children.
- Make sure you take antibiotics as prescribed.
If your pneumonia becomes so severe that you are treated in the hospital, you may receive fluids and antibiotics in your veins, oxygen therapy, and possibly breathing treatments. You are more likely to be admitted to the hospital if you:
- Have another serious medical problem.
- Have severe symptoms.
- Are unable to care for yourself at home, or are unable to eat or drink.
- Are older than 65 or a young child.
- Have been taking antibiotics at home and are not getting better.
Viral Pneumonia: Typical antibiotics will not work for viral pneumonia; sometimes, however, your doctor may use antiviral medication. Viral pneumonia usually improves in one to three weeks.
Bacterial Pneumonia: Patients with mild pneumonia who are otherwise healthy are sometimes treated with oral macrolide antibiotics (azithromycin, clarithromycin, or erythromycin). Patients with other serious illnesses, such as heart disease, chronic obstructive pulmonary disease (which includes chronic bronchitis and emphysema), kidney disease, or diabetes are often given more powerful or higher dose antibiotics.
In addition to antibiotics, treatment includes: proper diet and oxygen to increase oxygen in the blood when needed. In some patients, medication to ease chest pain and to provide relief from a violent cough may be necessary.
Mycoplasma Pneumonia: These are pneumonias caused by germs intermediate between viruses and bacteria. These are frequently mild, but occasionally can be severe and prolonged.
What affects or complications can the disease have on the body?
People who may be more likely to have complications from pneumonia include:
- Older adults or very young children.
- People whose immune system does not work well.
- People with other, serious medical problems such as diabetes or cirrhosis of the liver.
Possible complications include:
- Respiratory failure, which requires a breathing machine or ventilator.
- Sepsis, a condition in which there is uncontrolled inflammation in the body, which may lead to widespread organ failure.
- Acute respiratory distress syndrome (ARDS), a severe form of respiratory failure.
- Lung abscesses - these are infrequent, but serious, complications of pneumonia. They occur when pockets of pus form inside or around the lung. These may sometimes need to be drained with surgery.
