Pneumonia is a lung infection that has a number of potential causes. This can be a dangerous illness with life-threatening effects.
It normally starts with a bacterial , viral, or fungal infection.
The lungs get inflamed, and the tiny air sacs, or alveoli, fill up with fluid inside the lungs.
In young and healthy people, pneumonia can occur but it is most dangerous for older adults , infants, people with other diseases, and those with impaired immune systems.
In the United States ( U.S.), the hospital treats about 1 million patients a year for pneumonia, and approximately 50,000 die from the disease.
Important facts about pneumonia
Here are a few key points about pneumonia. More details are given in the main article.
- Pneumonia is an infection of the lungs that can cause mild to severe illness in people of all ages.
- It is the leading cause of death due to infection in children younger than 5 years of age worldwide.
- Pneumonia and influenza together are ranked as the eighth leading cause of death in the U.S.
- Those at high risk for pneumonia include older adults, the very young, and people with underlying health problems.
Symptoms

The first pneumonia signs usually resemble those of a cold or flu. The person then develops a high sputum fever , chills, and cough.
Common symptoms include:
- cough
- rusty or green phlegm, or sputum, coughed up from lungs
- fever
- fast breathing and shortness of breath
- shaking chills
- chest pain that usually worsens when taking a deep breath, known as pleuritic pain
- fast heartbeat
- fatigue and weakness
- nausea and vomiting
- diarrhea
- sweating
- headache
- muscle pain
- confusion or delirium, especially in older adults
- dusky or purplish skin color, or cyanosis, from poorly oxygenated blood
Symptoms can vary depending on other underlying conditions and the type of pneumonia.
Treatment
Treatment depends on the type and severity of the pneumonia.
- Bacterial types of pneumonia are usually treated with antibiotics.
- Viral types of pneumonia are usually treated with rest and plenty of fluids. Antiviral medications can be used in influenza.
- Fungal types of pneumonia are usually treated with antifungal medications.
Doctors generally prescribe over-the-counter ( OTC) medicines to help manage the pneumonia symptoms. Which include medications to reduce fever, to reduce aches and pains, and to prevent cough.
In addition , it is crucial to rest and drink plenty of fluids. Staying hydrated helps thin down the thick phlegm and mucus, making cough easier.
Pneumonia hospitalization may be appropriate if the symptoms are especially severe, or if an individual has a weakened immune system or other serious illnesses.
Patients in hospital are generally treated with intravenous antibiotics and fluids. They can need a supplemental supply of oxygen.
In children
In most children they may be protected from pneumonia by the immune system. If a child does develop pneumonia, it is usually due to a virus.
Symptoms include:
- difficulty breathing
- not feeding properly
- coughing
- fever
- irritability
- dehydration
Toddlers may complain of chest pain, and may vomit after coughing.
Treatment involves plenty of rest, and regular fluid intake. The doctor can recommend over-the-counter for abdominal problems but it won’t help with cough medicines. Adults should not smoke around children , especially when pneumonia is present.
Causes
The primary cause of pneumonia are bacteria and viruses. Pneumonia-causing germs may settle and multiply in the alveoli after a person breathes them in.
Pneumonia can be infectious. The pneumonia-inducing bacteria and viruses are usually inhaled.
They can be passed on through coughing and sneezing, or spread through touch to shared objects.
To attack the infection, the body sends in white blood cells. That is why it inflames the air sacs. The bacteria and viruses fill the lung sacs with pus and fluid, causing pneumonia.
Risk factors
Those most at risk include people who:
- are aged under 5 years or over 65 years
- smoke tobacco, consume large amounts of alcohol, or both
- have underlying conditions such as cystic fibrosis, chronic obstructive pulmonary disorder (COPD), asthma, or conditions that affect the kidneys, heart, or liver
- have a weakened or impaired immune system, due, for example, to AIDS, HIV, or cancer
- take medicines for gastroesophageal reflux disease (GERD)
- have recently recovered from a cold or influenza infection
- experience malnutrition
- have been recently hospitalized in an intensive care unit
- have been exposed to certain chemicals or pollutants
Some groups are more prone than others to pneumonia, including Native Alaskan or certain Native American ethnicities.
Types
There are different types of pneumonia, depending on their cause.
- Bacterial pneumonia: The most common cause is the bacterium Streptococcus pneumoniae (S. pneumoniae), but many different bacteria can cause pneumonia
- Viral pneumonia: This can result from the respiratory syncytial virus (RSV) and influenza types A and B, known as the flu
- Aspiration pneumonia: This can happen when a person breathes food, liquids, or stomach contents into the lungs. This type is not contagious.
- Fungal pneumonia: This can result from a condition such as valley fever, caused by the Coccidioides fungus.
- Hospital-acquired pneumonia: This can occur in patients being treated for other conditions, for example, those attached to a respirator, or breathing machine.
Regardless of the cause, the signs and symptoms will be similar.
Prevention
There are two distinct vaccines to prevent pneumococcal disease, the most common cause of pneumonia in the bacteria.
These contain a wide variety of pneumococcal infections and, depending on their health conditions, are recommended for both children and adults.
- pneumococcal conjugate vaccine, or Prevnar
- pneumococcal polysaccharide vaccine, or Pneumovax

Prevnar (PCV13) is usually used as part of routine immunizations of an child.
It is recommended for children under 2 years of age, for adults over 65 years of age and for those between 2 and 64 years of age who have other medical conditions.
Pneumovax (PPSV23) is recommended for children and adults at greater risk of pneumococcal infection.
This includes:
- adults aged 65 years or older
- people with diabetes
- those with chronic heart, lung, or kidney disease
- people who consume large amounts of alcohol or who smoke
- those without a spleen
For 2 to 64 years of age with some other medical conditions may be recommended to have this vaccine
The vaccine does not entirely protect older adults from pneumonia, but may significantly reduce the risk of developing pneumonia and other S-caused infections. Pneumoniae), including infections of a blood and brain.
In addition to vaccines, physicians recommend:
- regular hand washing
- covering the mouth and nose when coughing or sneezing
- refraining from smoking
- eating healthfully
- exercising 5 days a week
- staying away from the sputum or cough particles of others with pneumonia
The majority of people recover within 1 to 3 weeks from pneumonia. Those at risk of severe symptoms should ensure their vaccinations were also maintained.
Diagnosis
A doctor will talk about symptoms and medical history and do a physical exam.

When listening to the chest through a stethoscope, they can suspect pneumonia if they hear coarse breathing , wheezing, crackling, or can sounds of breath.
The doctor may also check the levels of oxygen in the blood with a painless finger monitor called a pulse oximeter.
Chest X-rays can confirm a pneumonia diagnosis and show which areas of the lungs are affected.
A CT scan of the chest may provide more detailed information.
Blood tests measure the white blood cell count.
This helps determine how serious the infection is, and whether the likely cause is a bacteria, virus or fungus.
Blood cultures may reveal whether the microorganism from the lungs has spread into the blood stream.
An arterial blood gas (ABG) blood test may provide a more accurate reading of the body’s oxygen and carbon dioxide levels and other factors.
A sputum analysis can determine which organism is causing the pneumonia.
A bronchoscopy is sometimes used for further investigation.
A thin, flexible and lighted tube called a bronchoscope is passed down into the lung. That helps the doctor to inspect the contaminated sections of the airways and lungs directly. The patient is under anesthetic.A thin, flexible, and lighted tube called a bronchoscope is passed down into the lungs. This enables the doctor to examine directly the infected parts of the airways and lungs. The patient is under anesthetic.