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What is Pneumonia ?
Pneumonia is an inflammation of the
lungs and respiratory system. It is caused by infection with
viruses, bacteria fungi, parasites or other organisms in which
the alveoli becomes inflamed and flooded with fluid. Pneumonia
is generally caused may be due to the chemical or physical
injury to the lungs or indirectly through any other medical
illness such as influenza, lung cancer or alcohol abuse. Though
these infections are not directly responsible for pneumonia they
trigger the disease indirectly by increasing the bacterial
growth.
Causes
As explained earlier the causes of pneumonia can be bacteria,
viruses, parasites, fungi or other organisms. But the main
causes of pneumonia are the bacteria. The severity of the
pneumonia can be determined by knowing whether the bacteria are
gram positive or gram negative. These can be detected by
visualizing the bacteria under a microscope using stains. Gram
positive bacteria appear blue on the stain and examples include
Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus
aureus etc. Similarly, gram negative bacteria appear pink on the
stain and examples include Haemophilus influenzae, E.coli,
Pseudomonas aeruginosa, Enterobacter etc.
Types of Pneumonia
There are several different ways of classifying pneumonia. They
are classified based on the micro organisms, anatomic changes
that were found in the lungs, radiological classification. Other
factors that classify pneumonia include age, lung disease, risk
factors of certain micro organisms etc.
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Based on the above there are
different types of pneumonia that includes
Aspiration pneumonia: It is caused by aspirating oral or gastric
contents that may contain anaerobic bacteria that result in the
lung inflammation.
Severe Acute Respiratory Syndrome (SARS): It is the most
dangerous type of pneumonia that is caused by the SARS
coronavirus, a pathogen.
Eosinophilic Pneumonia: This is the inflammation of the lungs by eosinophils that is a particular kind of white blood cell. It
can be caused may be due to the infection with a parasite or
exposure to environmental factors.
Bronchiolitis Abliterans Orgnising Pneumonia (BOOP): It is also
known as cryptogenic organising pneumonitis (COP) and is caused
by inflammation of the small airways of the lungs.
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Chemical pneumonia: it is caused by some chemical toxins such as
pesticides that enters the body through either skin contact or
by inhalation.Apart from the above classification, it can also be classified
based on the disease by locations in the lung and by origin of
infection.
Based on the locations in the lung
it can be classified as
Lobar pneumonia: pneumonia occurs in one lobe of the lung.
Bronchopneumonia.
Based on the origin of infection it can be classified as
Hospital acquired pneumonia: pneumonia that is developed
within the hospital limits are called hospital acquired
pneumonia.
Community acquired pneumonia: this is developed outside the
hospital limits and often follows a viral respiratory infection.
Signs and Symptoms of Pneumonia
The symptoms of pneumonia vary depending on the age and the
cause.
The common symptoms include
Chest pain.
Rapid heart rate.
Fever.
Cough. Sometimes the sputum may contain pus or blood during
coughing.
Chills.
Abdominal pain.
Low blood pressure.
Vomiting.
Loss of appetite.
Difficulty in breathing.
In serious cases the patients lips and fingernails may turn
blue in colour.
When the infection is caused by bacteria the result is quicker
when compared to that caused by viruses.
Diagnosis
The diagnosis for pneumonia is done based on the history of the
patient and physical examination.
History of the Patient: The patients history such as smoking, alcohol or drug abuse,
recent respiratory infection, exposure to people with pneumonia,
recent travel etc are very important for the doctor to diagnose
the patient. The patient must be 100% sure about the things
reported.
Physical Examination:
Crackling sounds in the chest are detected using a stethoscope.
Such sounds heard while the patient is lying down are a clear
case of pneumonia. There is another test known as percussion
done by the doctors. The test includes tapping of the patients
chest lightly. If a dull thud noise instead of a healthy drum
like sound indicates pneumonia. The dull noise is either due to
the condition known as Consolidation in which the lungs become
firm and elastic or due to fluid build-up in the space between
the lungs and the lining around it. This condition of the lungs
is known as Pleural effusion.
Laboratory Tests:
There are certain laboratory tests conducted to diagnose the
infection and to identify the bacteria. The tests that generally
conducted are:
Blood tests.
Urine tests.
Sputum tests.
Blood Tests: These tests are conducted to:
Find the white blood cell count. High levels of white blood
cells indicate infection.
Detect antibodies to S. pneumoniae. It is supposed to be not
that accurate.
Perform blood cultures. These are performed to find out the
specific organism that causes pneumonia.
Urine tests: The urine tests are done to find out the
S.pneumoniae within fifteen minutes and are considered to be 93%
accurate.
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Sputum Tests: An adequate sputum
sample is taken from the patient after a shallow cough. This is
tested for the infecting organism. Before sending the sample for
test to the laboratory the presence of the following are noted:
Colour and consistency. If the sputum is coloured yellow,
brown or green then the infection is definite.
Presence of blood.
Other tests include chest X-rays and other imaging techniques:
Chest X-rays are done to find infiltrates in the lung, fluids
around the lungs which indicates infection. Other imaging
techniques such as Computed tomography (CT) or MRI scans are
done if the x-rays are not clear, when the condition is serious
or complicated, when patients do not respond to antibiotics.
Imaging techniques cannot determine the organisms causing the
infection.
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Invasive Diagnostic Procedures
These procedures are conducted when the patient is having life
threatening complications, failed standard treatments or when AIDS
is present. The procedures conducted are:
Bronchoscopy.
Thoracentesis.
Lung biopsy.
Bronchoscopy:
The patient is given anesthesia, sedatives and supplementary oxygen.
He/she is inserted with a fiberoptic tube into the lower respiratory
tract through nose or mouth. This done for the physician to view the
wind-pipe and airways for pus, abnormal mucus and other problems.
The procedure is suppose to be safe but is associated with certain
complications such as allergies due to sedatives or anesthetics.
Thoracentesis: If the presence of pus is seen in the lungs then thoracentesis is performed. The fluid in the pleura is withdrawn
using a long needle which is inserted between the ribs. The fluid is
then tested using gram stains, blood cell counts, chemical tests
etc. These also include certain complications.
Lung Biopsy: This is done for people with extreme cases of pneumonia
where the diagnosis is unclear particularly in patients with damaged
immune systems.
This can be performed in two ways that include:
Surgically using anesthesia.
A lung tap.
Surgically using Anesthesia
The procedure in this involved removal of damaged tissues in the
lungs and in extreme cases removal of the entire lobe. It is done by
giving anesthesia and an incision.
A lung Tap:
This procedure is known by a number of different names such as
thoracic puncture, lung puncture, lung aspiration, transthoracic
needle aspiration, needle aspiration, percutaneous needle aspiration
etc. In this procedure a needle is inserted between the ribs to
collect the fluid out of the lung for examination.
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Article Contributed By: Sukanya Banerjee
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