What are the different types of pneumonia?

Photo of a doctor listening to a patient’s lung
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There are different types of . Determining the type helps doctors to describe the disease more precisely and – more importantly – to find the most suitable treatment.

The various types of are classified according to a number of factors. To determine the most suitable treatment, it's important to know whether somebody caught at home, in a hospital, or in a nursing home.

Community-acquired and nosocomial pneumonia

If you develop at home, it's referred to as community-acquired (or CAP for short), even if you are admitted to the hospital during the course of the illness.

If you develop while in a hospital, it is called hospital-acquired (HAP for short) or nosocomial . Pneumonia is considered to be nosocomial if it starts at least two days after you are admitted to the hospital, or within three months of a hospital stay.

Nosocomial can also develop in a retirement home or nursing home, or at a medical facility such as a dialysis center.

Why is classification important for the treatment?

Community-acquired is usually caused by pneumococci (), whereas nosocomial is often caused by staphylococcus , various intestinal (bowel) , and certain other such as Pseudomonas aeruginosa. Some of these can be multidrug-resistant, meaning they are resistant to several . Because of this, different are usually needed for nosocomial than for community-acquired .

Mild, moderate or severe pneumonia

To be able to provide the right treatment, doctors also classify community-acquired as mild, moderate or severe. They take the risk of complications into account as well.

Pneumonia is considered to be mild with no increased risk if the patient

  • is younger than 65 years old,
  • is able to think and communicate clearly,
  • has a normal blood pressure and pulse,
  • isn't breathing too fast (not more than 30 breaths per minute),
  • has enough oxygen in their blood,
  • hasn't been given any in the past three months,
  • hasn't been in a hospital in the past three months, and
  • doesn't have any other severe medical conditions.

People with mild can be treated at home and are given antibiotic tablets.

People are diagnosed with moderate if they have symptoms such as drowsiness and confusion, low blood pressure, worsening shortness of breath, and risk factors such as old age and other diseases. They then need to have treatment at a hospital. Some will be given a combination of two different , at least at the beginning of the treatment.

Pneumonia is considered to be severe if vital organs or systems such as the heart, the kidneys or the circulatory system are at risk of failing, or if the lungs can no longer absorb enough oxygen. People then usually need treatment with through a drip (infusion) in the intensive care unit of a hospital. Sometimes other treatments are needed too, for instance with steroids or artificial respiration.

Pneumonia in children is only classified as either “not severe” or “severe.”

How can pneumonia be described more precisely?

Experts also classify according to factors other than where the patient was infected and the severity. But that typically doesn't affect how the is treated. Instead, it helps doctors to describe the disease better.

Atypical pneumonia (walking pneumonia)

Typical generally begins with a sudden high fever and chills, and then coughing with phlegm comes later.

Atypical is caused by other germs, which are also referred to as "atypical.” Older people in particular have fewer or slightly different symptoms if they have atypical : It then starts off rather slowly with a mild fever and/or headache and joint pain. Rather than coughing with phlegm, they tend to have a dry cough.

Atypical symptoms don't mean that the lungs are less severely inflamed or that the course of the disease will be milder, though.

Upper, middle and lower lobe pneumonia

X-rays play an important role in distinguishing between these types: If an entire part of the lung (lobe) is visibly inflamed, it is known as lobar . Depending on which lung lobe is affected, the is referred to as upper, middle or lower lobe .

If there are several areas of across different lung lobes, it is known as multilobar . If the started in airway passages (), it is called bronchopneumonia.

Sometimes, it's the air sacs that are more inflamed (alveolar ), and sometimes the tissue between the air sacs (interstitial ).

Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin (DEGAM). DEGAM-Leitlinie Nr. 11: Husten. AWMF-Registernr. 053-013. April 2014.

Deutsche Gesellschaft für Pädiatrische Infektiologie (DGPI), Gesellschaft für Pädiatrische Pneumologie (GPP). S2k-Leitlinie „Management der ambulant erworbenen Pneumonie bei Kindern und Jugendlichen (pädiatrische ambulant erworbene Pneumonie, pCAP)“. AWMF-Registernr.: 048-013. March 2017.

Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin (DGP). S3-Leitlinie: Behandlung von erwachsenen Patienten mit ambulant erworbener Pneumonie und Prävention – Update 2016. February 15, 2016.

Herold G. Innere Medizin. Cologne: Self-published; 2017.

Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. New York: McGraw-Hill; 2015.

Lux LJ, Posey RE, Daniels LS, Henke DC, Durham C, Jonas DE et al. Pharmacokinetic/Pharmacodynamic Measures for Guiding Antibiotic Treatment for Hospital-Acquired Pneumonia. November 2014. (AHRQ Comparative Effectiveness Reviews; Volume 136).

National Institute for Health and Care Excellence (NICE). Pneumonia: Diagnosis and Management of Community- and Hospital-Acquired Pneumonia in Adults. December 03, 2014. (NICE Clinical Guidelines; Volume 191).

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on May 18, 2021
Next planned update: 2024

Authors/Publishers:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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