Pneumonia is an infection in one or both lungs. It can be caused by bacteria, viruses, or fungi. The bacterial form is the most common type in adults. It causes inflammation in the air sacs in your lungs, which are called alveoli. The alveoli fill with fluid or pus, making it difficult to breathe.
There are different types of pneumonia. They include :
- Community-acquired (CAP) : The most common type of pneumonia. It occurs in people who are not in the hospital or other healthcare facility.
- Hospital-acquired: Type of pneumonia you can develop during or after staying in a hospital.
- Healthcare-acquired: Type of pneumonia you can get in nursing homes, outpatient clinics, or centers for dialysis.
- Aspiration: You can get this type of pneumonia if you breathe large amounts of liquids, vomit, or food or other objects into your lungs. This can happen when you have a medical condition that affects your ability to swallow (e.g., seizure ).
Classification according to the organism that causes the infection.
- Bacterial pneumonia: The most common cause of bacterial pneumonia is Streptococcus pneumoniae. Chlamydophila pneumonia and Legionella pneumophila can also cause bacterial pneumonia.
- Viral pneumonia: Respiratory viruses are often the cause of pneumonia, especially in young children and older people. Viral pneumonia is usually not serious and lasts for a shorter time than bacterial pneumonia.
- Mycoplasma pneumonia: Mycoplasma organisms are not viruses or bacteria, but they have traits common to both. Mycoplasmas generally cause mild cases of pneumonia, most often in older children and young adults.
- Fungal pneumonia: Fungi from soil or bird droppings can cause pneumonia in people who inhale large amounts of the organisms. They can also cause pneumonia in people with chronic diseases or weakened immune systems.
- Pneumonia is an infection of the lung. The lungs fill with fluid and make breathing difficult.
- Pneumonia disproportionately affects the young, the elderly, and the immunocompromised. It preys on weakness and vulnerability.
- Pneumonia is the most common cause of sepsis and septic shock, causing 50% of all episodes.
- In the US, it is less often fatal for children, but it is still a big problem. Pneumonia is the most common reason for US children to be hospitalized.
- Antibiotic resistance is growing amongst the bacteria that cause pneumonia. This often arises from the overuse and misuse of antibiotics in and out of the hospital. New and more effective antibiotics are urgently needed.
- While young healthy adults have less risk of pneumonia than the age extremes, it is always a threat. Half of all non-immunocompromised adults hospitalized for severe pneumonia in are younger adults (18-57 years of age). Half the deaths from bacteremic pneumococcal pneumonia occur in people ages 18-64.
- Older people have higher risk of getting pneumonia, and are more likely to die from it if they do.
- Pneumonia is the world’s leading cause of death among children under 5 years of age, accounting for 15% of all deaths of children under 5 years old. There are 120 million episodes of pneumonia per year in children under 5, over 10% of which (14 million) progress to severe episodes. There was an estimated 935,000 deaths from pneumonia in children under the age of five in 2013.
- Pneumonia can develop in patients already in the hospital for other reasons. Hospital-acquired pneumonia has a higher mortality rate than any other hospital-acquired infection.
- Pneumonia can be caused by lots of different types of microbes, and no single one is responsible for as many as 10% of pneumonia cases. For most pneumonia patients, the microbe causing the infection is never identified.
- Vaccines are available for some but not many causes of pneumonia. The influenza vaccine is effective for those strains circulating that year, so it should be taken again every year. The pneumococcal pneumonia vaccines are recommended for those in higher risk groups (children, immunocompromised individuals, and seniors).
- Around the world, viral pneumonias are the leading cause of hospitalization of infants. The World Health Organization has set a high priority on developing new vaccines and new therapeutic drugs to tackle these viral pneumonias that largely have no currently available vaccines or treatments.
- Antibiotics can be effective for many of the bacteria that cause pneumonia. For viral causes of pneumonia, antibiotics are ineffective and should not be used. There are few or no treatments for most viral causes of pneumonia.
Signs and Symptoms
- Chest pain when you breathe or cough.
- Confusion or changes in mental awareness (in adults age 65 and older).
- Cough, which may produce phlegm.
- Fever, sweating and shaking chills
- Lower than normal body temperature (in adults older than age 65 and people with weak immune systems).
- Nausea, vomiting or diarrhea.
- Shortness of breath.
Causes and Risk Factors
Many germs can cause pneumonia. The most common are bacteria and viruses in the air we breathe. Your body usually prevents these germs from infecting your lungs. But sometimes these germs can overpower your immune system, even if your health is generally good. This can affect anyone. But the two age groups at highest risk are children who are 2 years old or younger and people who are age 65 or older
Other risk factors include:
- Being hospitalized. You’re at greater risk if you’re in a hospital intensive care unit, especially if you’re on a machine that helps you breathe (a ventilator).
- Chronic disease. You’re more likely to get pneumonia if you have asthma, chronic obstructive pulmonary disease (COPD) or heart disease.
- Smoking. Smoking damages your body’s natural defenses against the bacteria and viruses that cause pneumonia.
- Weakened or suppressed immune system. People who have HIV/AIDS, who’ve had an organ transplant, or who receive chemotherapy or long-term steroids are at risk.
How Is the disease diagnosed?
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 may also be done.
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 (or CAT) 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 lungs’ airways, which would be performed if you are hospitalized and antibiotics are not working well.
How Is Pneumonia Treated?
Treatment depends on the type 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.
- Practice good hygiene. To protect yourself against respiratory infections that sometimes lead to pneumonia, wash your hands regularly or use an alcohol-based hand sanitizer.
- Get vaccinated. Vaccines are available to prevent some types of pneumonia and the flu. Talk with your doctor about getting these shots. The vaccination guidelines have changed over time so make sure to review your vaccination status with your doctor even if you recall previously receiving a pneumonia vaccine.
- Make sure children get vaccinated. Doctors recommend a different pneumonia vaccine for children younger than age 2 and for children ages 2 to 5 years who are at particular risk of pneumococcal disease. Children who attend a group child care center should also get the vaccine. Doctors also recommend flu shots for children older than 6 months.
- Don’t smoke. Smoking damages your lungs’ natural defenses against respiratory infections.
- Keep your immune system strong. Get enough sleep, exercise regularly and eat a healthy diet.
- Avoid contact with sick people; if you are sick, limit contact with others as much as possible.
- Wash your hands regularly; wipe down regularly touched surfaces, such as door knobs.
- Cough and sneeze into a tissue or into your arm sleeve (instead of your hands).