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Emphysema (chronic pulmonary disease) and smoking
Cause: The tar in smoke is deposited in the airways. The ciliated epithelium are paralysed or destroyed
by the tar, and goblet cells are stimulated to produce more
mucus. This results in the build up of dust, bacteria, viruses
and cells and mucus. Pathogens are not wafted out of the
airway by cilia and infections and inflammation often occur.
White blood cells (phagocytes,) to get out of the blood and
into the lungs produce an enzyme known as elastase which
breaks down the elastic fibres (elastin) in the alveoli and
As the smoker exhales, the alveoli walls do not recoil to
push air out. The bronchioles often collapse, trapping air in
the alveoli and causing them to burst as air pressure changes.
Emphysema frequently occurs with chronic bronchitis, and together the diseases are called chronic
obstructive pulmonary disease (COPD).
After a longer period, hyperventilating will not provide the oxygen needed, so blood pressure to the lungs
increases (pulmonary hypertension.) As blood to the lungs is pumped from the right side of the heart,
stain is placed on the right side of the heart and the muscle thickens. The uneven distribution of
blood flow can also cause
Left: photomicrograph of lung
tissue from mice. A) Exposed
to air and B) exposed to
cigarette smoke for 6 months.
Notice the enlarged air spaces
The lungs now have a reduced surface area as there are larger air spaces. There is less surface area
for gaseous exchange so smokers will often fell out of breath or feel fatigue.
Eventually, there may come a point when every breath requires a major effort and the patient is disabled
and unable to carry out normal activities.
Due to the lack of oxygen, the heart pumps faster and blood pressure
increases. Resistant blood flow is a result of the blood being pushed
through vessels at a higher pressure.
Smokers cough is also a connected symptom.
The doctor will perform a number of tests including
Pulmonary Function Testing (PFT) This test involves a series of breathing manoeuvers that
measure the airflow and volume of air in your lungs.
High Resolution Computed Tomography (HRCT) This is a special type of CT scan that provides
your doctor with highresolution images of your lungs. Having a HRCT is no different than having a
regular CT scan they both are performed on an openair table and take only a few minutes.
Chest XRay help to confirm diagnosis of emphysema and rule out other conditions
Arterial Blood Gases Analysis These blood tests measure how well your lungs transfer oxygen to
your bloodstream and remove carbon dioxide.
Heather Grant 11R November 2008