Atypical pneumonia
What is Atypical pneumonia? Atypical pneumonia refers to
pneumonia caused by certain bacteria, such as, Legionella
pneumophila, Mycoplasma pneumoniae and Chlamydophila pneumoniae.
While atypical pneumonias are commonly associated with milder
forms of pneumonia, pneumonia due to Legionella, in particular,
can be quite severe and lead to high mortality rates.
Causes
Atypical pneumonia due to Mycoplasma and Chlamydophila usually
cause milder forms of pneumonia and characterized by a more
drawn out course of symptoms unlike other forms of pneumonia
which can come on more quickly with more severe early symptoms.
Mycoplasma pneumonia often affects younger people and can
be associated with symptoms outside of the lungs, such as
anemia and rashes, and neurological syndromes such as meningitis,
myelitis, and encephalitis. Severe forms of Mycoplasma pneumonia
have been described in all age groups.
Chlamydophila pneumonia occurs year round and accounts for
5-15% of all pneumonias. It is usually mild with a low mortality
rate. In contrast, atypical pneumonia due to Legionella accounts
for 2-6% of pneumonias and has a higher mortality rate.
Elderly people, smokers, and people with chronic illnesses
and weakened immune systems are at higher risk for this type
of pneumonia. Contact with contaminated aerosol systems, like
infected air conditioning systems have also been associated
with pneumonia due to Legionella.
Symptoms
Chills
Fevers
Cough
Headache
Muscle stiffness and aching
Rapid breathing
Shortness of breath
Loss of appetite
Malaise
Confusion . . .especially with Legionella
Rash . . . especially with Mycoplasma
Diarrhea . . . especially with Legionella
Exams and Tests
People with suspected pneumonia should undergo a medical
evaluation, including a thorough physical exam and a chest
x-ray, especially since the physical exam may not always distinguish
pneumonia from acute bronchitis or other respiratory infections.
Depending on the severity of illness, additional studies,
such as a complete blood count, blood cultures, and sputum
cultures, may be obtained.
When certain forms of atypical pneumonia are suspected, tests
of your urine or a throat swab may be ordered as well.
Treatment
The mainstay of treatment for atypical pneumonia is antibiotic
therapy. In mild cases, treatment with oral antibiotics at
home may be appropriate. Severe cases, which is common with
pneumonia caused by Legionella may require intravenous antibiotics
and oxygen supplementation.
Antibiotics with activity against these organisms include
-- erythromycin, azithromycin, clarithromycin, fluoroquinolones
and their derivatives (such as levofloxacin), and tetracyclines
(such as doxycycline).
Outlook. . . Prognosis
Most patients with pneumonia due to Mycoplasma or Chlamydophila
do well with appropriate antibiotic therapy, although there
is a small chance of relapse if antibiotics are used for too
short a period of time, which is less than two weeks.
In the case of pneumonia due to Legionella, severe illness
occurs particularly among the elderly and those with chronic
diseases and weakened immune systems. It is associated with
a higher mortality rate.
Possible Complications
- Respiratory failure, mechanical ventilation, especially
in severe forms of pneumonia due to Legionella
- Rash and hemolytic anemia, especially associated with
pneumonia due to Mycoplasma
When to Contact a Medical Professional
Seek medical evaluation if you develop fevers, cough, and/or
shortness of breath. While there are numerous causes for these
symptoms, you will need to be evaluated for pneumonia.
Prevention
There are no proven methods for preventing atypical pneumonia,
and no vaccinations are available at this time for atypical
pneumonias.
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