Pneumonia: Defined


Pneumonia is a lung infection that can affect one or both lungs. Different types of germs and irritants can cause the illness — from viruses and bacteria to fungi and inhaled chemicals.

Pneumonia can range from mild to severe. According to the Centers for Disease Control and Prevention, pneumonia is the leading cause of death among children younger than 5 across the globe. Those older than 65 also face an increased risk.

Pneumonia can be both prevented and treated through avoiding irritants, vaccines, antibiotics and antiviral medications.


Anyone experiencing symptoms of pneumonia should seek immediate medical care, as pneumonia can be life-threatening if left untreated.

Common symptoms of pneumonia include high fever, a low body temperature or chills, a persistent cough that produces phlegm, chest pain or shortness of breath, diarrhea, nausea and vomiting.

Symptoms can vary in infants and the elderly. For example, infants sometimes do not exhibit symptoms at all and instead appear restless or overly tired. The elderly may have sudden, sharp changes in mental awareness when they have pneumonia, according to the Mayo Clinic.


Using a combination of lab tests, a physical exam and your medical history, your doctor will diagnose or rule out pneumonia.

doctor looking at x-rayTo locate the infection and assess its severity, your doctor may give you a chest X-ray. Some doctors choose to use blood tests to confirm an infection and identify the specific type of infection. However, according to the Mayo Clinic, only about half of patients receive an exact identification of the organism causing the infection.

Other tests include pulse oximetry, which measures the level of oxygen in your blood. Since pneumonia can prevent your lungs from moving enough oxygen into your bloodstream, this test can identify the presence of pneumonia or a similar illness. Another common test is the sputum test, which analyzes a sample of fluid from the lungs for the presence of pneumonia.


Pneumonia is an infection, so doctors treat it by resolving the infection. They can do this with a variety of methods, but some of the most common ones are antibiotics and antivirals. Antibiotics fight bacterial infections, and antivirals fight viral infections, so your doctor will prescribe one or the other based on what type of pneumonia you have.

antibiotics and thermometerInfants and the elderly are commonly hospitalized for pneumonia, but it can land others in a hospital bed, too — especially if your blood pressure drops to unsafe levels or you are vomiting so much that you can’t keep medications down.

If you have pneumonia, your doctor is likely to prescribe bed rest in conjunction with any other treatment.


Causes of pneumonia can vary widely — each case isn’t the result of the same particular organism or irritant. In other words, many different kinds of bacteria, viruses and fungi can cause pneumonia.

Streptococcus pneumoniae is a type of bacteria that can cause pneumonia, often after a cold or the flu when the respiratory system is already weakened. Sometimes, viruses that cause the flu can also cause pneumonia. Some types of viral pneumonia are more mild than bacterial pneumonia, but all cases should be taken seriously.

Fungi do not typically cause pneumonia in healthy adults. Those with weakened immune systems or who have come into contact with a large amount of the fungi are most susceptible.

Mycoplasma pneumoniae is a bacteria-like organism that can cause what’s known as walking pneumonia — “walking” because it isn’t usually severe enough to banish patients to bed rest.


Pneumonia-like symptoms should always be taken seriously. If left untreated, especially in infants and the elderly, pneumonia can be deadly. Most primary care doctors and emergency rooms are equipped to treat pneumonia and its symptoms.


Preventing pneumonia is better than treating an actual case. Many factors can reduce the risk for pneumonia. These factors include:

  • Not smoking
  • Getting vaccinated for pneumonia
  • Getting a seasonal flu shot
  • Regularly washing your hands
  • Sanitizing surfaces that are likely to carry bacteria and other germs, such as kitchen counters

Talk to your doctor before getting a pneumonia vaccine or flu shot.


Pneumonia is often short-lived and easily treated. However, during recovery time, it’s important to get lots of rest, even if you’re feeling better. Also, be sure to drink plenty of water or other healthy fluids, stay home from work or school to prevent the infection from spreading and take all prescribed medications.

Recovery times can vary from two or three weeks in healthy patients to much longer in patients with already compromised health. Taking precautions can shorten recovery times.

Centers for Disease Control and Prevention, “Pneumonia: An Infection of the Lungs”
MedlinePlus, “Pneumonia”
Mayo Clinic, “Pneumonia”