9. Radiological Imaging:
Chest x-ray : An x-ray exam will allow your doctor to see your lungs, heart and
blood vessels to help determine if you have pneumonia. When interpreting the
x-ray, the radiologist will look for white spots in the lungs (called infiltrates) that
identify an infection. This exam will also help determine if you have any
complications related to pneumonia such as abscesses or pleural effusions (fluid
surrounding the lungs).
CT of the lungs: A CT scan of the chest may be done to see finer details within the
lungs and detect pneumonia that may be more difficult to see on a plain x-ray. A
CT scan also shows the airway (trachea and bronchi) in great detail and can help
determine if pneumonia may be related to a problem within the airway. A CT scan
can also show complications of pneumonia, abscesses or pleural effusions and
enlarged lymph nodes.
Ultrasound of the chest : Ultrasound may be used if fluid surrounding the lungs is
suspected. An ultrasound exam will help determine how much fluid is present and
can aid in determining the cause of the fluid.
MRI of the chest : MRI is not generally used to evaluate for pneumonia but may be
used to look at the heart, vessels of the chest and chest wall structures. If the
lungs are abnormal because of excess fluid, infection or tumor, an MRI may
provide additional information about the cause or extent of these abnormalities.
19. Atypical Bacterial Pneumonia.
Pneumonia is predominantly a clinical syndrome. The classic
etiologic agents of atypical pneumonia are Legionella species,
Mycoplasma pneumoniae, and Chlamydia pneumoniae. Many other
diseases, caused by various pathogens, should be considered in the
differential diagnosis. Such etiologic agents include fungi,
mycobacteria, parasites, and viruses (e.g., influenza virus,
adenovirus, respiratory syncytial virus, human parainfluenza virus,
measles, varicella zoster, Hantavirus).
In immunosuppressed patients, outbreaks of isolated cases of
respiratory virus infections with atypical presentations are reported.
These infections can be severe and may have concomitant bacterial
etiologies. In endemic areas, certain zoonotic infections should be
considered when patients present with atypical pneumonia.
Noninfectious etiologies must be considered in atypical and non-
resolving pneumonias.
30. Pneumocystis pneumonia (PCP) is an atypical pulmonary
infection and the most common opportunistic infection in
patients with acquired immunodeficiency syndrome (AIDS).
42. Radiographic features
Plain film
Bronchopneumonia is characterised by multiple small
nodular or reticunodular opacities which tend to be patchy
and confluent. This represents areas of lung where there
are patches of inflammation separated by normal lung
parenchyma .
The distribution is often bilateral and asymmetric, and
predominantly involves the lung bases.
CT - HRCT chest
Multiple foci of opacity can be seen in a lobular pattern,
centred at centrilobular bronchioles. These foci of
consolidation can overlap to create a larger
heterogeneous confluent area of consolidation. This may
result in a tree-in-bud appearance.