What is pneumonia? Symptoms, causes, diagnosis, treatment and prevention

How do you get pneumonia? Most of the germs that cause infection are passed from person to person through droplets, coughing or sneezing.

Young children and people over 65 are most vulnerable to pneumonia, notes the Mayo Clinic.

According to the National Heart, Lung, and Blood Institute (NHLBI), you are also at a higher risk for pneumonia if you have any of the following conditions:

People who smoke are at a higher risk for pneumonia, as are people who take immunosuppressive drugs and people who are frequently in tight and crowded spaces with others, such as students and military personnel.

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What types of pneumonia are there?

Your doctors will try to categorize your type of pneumonia to help guide your treatment.

Community acquired pneumonia (CAP)

It is the most common form of pneumonia because you can get it in public places, such as at school or at work. It can be caused by bacteria, viruses or fungi, according to the National Library of Medicine.

You can also develop CAP after contracting a viral infection, such as a cold or the flu or the SARS-CoV-2 virus, which causes COVID-19.

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CAP ranges from mild to severe and, if left untreated, can lead to respiratory failure or death.

Bacterial PAC is usually more serious than other types and is more common in adults. Atypical pneumonia, often called ambulatory pneumonia, is a milder form often caused by the bacteria Mycoplasma pneumoniae. Symptoms of walking pneumonia include sore throat, persistent dry cough, fatigue, headache, and fever, according to the Cleveland Clinic.

Various types of bacteria can be responsible for the disease. In most cases, the bacteria enter the lungs when inhaled and then travel into the bloodstream, potentially causing damage to other organs and systems in the body.

Streptococcus pneumoniae, also known as pneumococcal pneumonia, can be treated with antibiotics. But according to the Centers for Disease Control and Prevention (CDC), many types of bacteria, some of which S. pneumoniae (pneumococcus), are resistant to these antibiotics, which can lead to treatment failures. Pneumococcal pneumonia causes approximately 150,000 hospitalizations per year in the United States.

Risk factors for bacterial CAP include:

Have an underlying lung disease, such as asthma or COPD
Have a systemic disease, such as diabetes
Have a weakened immune system
Alcohol abuse
Smoking

Depending on your condition and if you have other health problems, your doctor may treat you for suspected bacterial pneumonia with antibiotics at home or in the hospital.

Getting the pneumococcal pneumonia vaccine lowers your risk of bacterial CAP, according to the CDC.

There are two different pneumonia vaccines; ask your doctor if you qualify for either.

Viral CAP, particularly respiratory syncytial virus (RSV), is the most common cause of pneumonia in children under one year of age, notes the CDC.

Antibiotics are ineffective against viral pneumonia. Your doctor will most likely treat the symptoms – fever, cough, and dehydration.

You or your child may need to be hospitalized if your symptoms of viral pneumonia get worse.

Nosocomial pneumonia

As the name suggests, this develops during a hospital stay for a different health problem. People who use machines to help them breathe are especially prone to developing hospital acquired pneumonia, notes MedlinePlus.

Hospital-acquired pneumonia usually needs to be treated in hospital with intravenous antibiotics.

Aspiration pneumonia

It can develop after a person inhales food, drink, vomit, or saliva into their lungs. After your lungs have been irritated by inhaling food or stomach contents, a bacterial infection may develop.

A strong gag reflex or cough will usually prevent aspiration pneumonia, but you may be at risk if you have trouble swallowing or if your level of alertness decreases.

This type of pneumonia can also occur in older people with poor swallowing mechanisms, such as stroke victims, according to MedlinePlus.

Aspiration pneumonia causes inflammation without bacterial infection. These pneumonia can sometimes be difficult to treat, especially since the patients are often sicker to begin with.

Some conditions that may put you at risk for aspiration pneumonia include:

Loss of alertness due to medications, illness, or surgery (under anesthesia)
Alcohol abuse
Old age
Poor gag reflex due to brain injury or stroke
Coma

Symptoms of aspiration pneumonia include coughing, increased sputum, fever, confusion, and shortness of breath.

Treatment may include respiratory support and intravenous antibiotics given in the hospital.

You can avoid complications by not eating or drinking before surgery, working with a therapist to learn how to swallow without sucking, and avoiding excessive alcohol consumption.

Opportunistic infection

Finally, Pneumocystis pneumonia is an extremely rare fungal pneumonia in healthy people, according to the CDC, but which develops in people with weakened immune systems; it is often referred to as an opportunistic infection.

You’re at risk of getting this type of pneumonia if you have chronic lung disease, have HIV or AIDS, or have had an organ transplant, notes the CDC.