How are different types of pneumonia classified?
Doctors classify different types of pneumonia into various groups. This allows them to describe the disease more exactly, and more importantly, to start off with the correct treatment.
The various types of pneumonia are classified according to a number of characteristics. To treat these types, it's essential to know whether somebody caught pneumonia at home, in a hospital, or in a nursing home.
Community-acquired and nosocomial pneumonia
If you develop pneumonia while in the hospital, it is called hospital-acquired (HAP for short) or nocosomial pneumonia. Pneumonia is considered to be nocosomial if it starts at least two days after you are admitted to the hospital, or within three months of a hospital stay.
Doctors can also classify pneumonia even more exactly, giving consideration to whether somebody became infected in a retirement or a nursing home, at a medical facility such as a dialysis center, or while receiving artificial respiration.
Why is classification important for the treatment?
Community-acquired pneumonia is usually caused by pneumococci, whereas nocosomial pneumonia is often connected with staphylococci, various intestinal bacteria, and special germs such as Pseudomonas aeruginosa. Some of those bacteria can be multi-resistant, meaning they are resistant to several antibiotics. That is why different antibiotics are usually need than for treating community-acquired pneumonia.
Mild, moderate or severe pneumonia
Pneumonia is considered to be mild with no increased risk if the patient
- is younger than 65 years old,
- is conscious and lucid,
- has normal blood pressure and pulse,
- is not breathing too fast (fewer than 30 breaths per minute),
- has enough oxygen in their blood,
- has not been given any antibiotics in the past three months,
- has not been in the hospital in the past three months, and
- does not have any other severe medical conditions.
The signs of moderate pneumonia include drowsiness and confusion, low blood pressure, worsening shortness of breath, and risk factors such as old age and underlying diseases. People with these symptoms need to have treatment at a hospital. Some will be given a combination of two different antibiotics, at least at the beginning of the treatment.
Pneumonia is classified as severe when the heart, the kidneys or the circulatory system are at risk of failing, or if the lungs can no longer take in enough oxygen. Treatment with an antibiotic infusion in intensive care is then usually needed, sometimes with artificial respiration or additional drugs such as corticosteroids.
Pneumonia in children is only classified as either “not severe” or “severe.”
How can pneumonia be described more exactly?
Experts also classify pneumonia according to factors other than where the patient was infected and the severity. But that typically doesn't affect how the pneumonia is treated. Instead, it's useful for getting a better description of the illness.
Typical pneumonia generally begins with a sudden high fever and chills, and then coughing with phlegm coming later.
Atypical pneumonia 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 pneumonia: It then starts off rather slowly with a mild fever and/or headache and aching limbs. Rather than coughing with phlegm, they have a dry, tickly cough.
Atypical symptoms don't mean that the lungs are less severely inflamed or that the disease will take a milder course though.
Upper, middle and lower lobe pneumonia
X-rays play an important role in distinguishing between these types: the term lobar pneumonia is used if an entire lung lobe is visibly inflamed. Depending on which lung lobe is affected, the pneumonia is referred to as upper, middle or lower lobe pneumonia.
If there are several multi-lobe focal inflammations in the lungs, the term focal pneumonia is used. Some people use the term bronchopneumonia if the focal inflammations started in inflamed airways (bronchi).
Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin (DEGAM). DEGAM-Leitlinie Nr. 11: Husten. AWMF-Registernr. 053-013. February 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).
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