Chronic
Obstructive Pulmonary Disease (COPD) Introduction: Chronic
obstructive pulmonary disease(=COPD) is a very common lung disease, mostly caused
by years of cigarette smoking. However, it is a spectrum of lung diseases where
the patient has problems breathing out. The medical language for this is having
a problem of "prolonged expiratory airflow". This is measured
with spirometry
and the result is that the ratio of the FEV1, the air that is breathed out in
1 second, to the forced vital capacity of the lung (=FVC) is reduced significantly.
This is understood best with flow volume curves as explained under the spirometry
link. However, in simple terms it is merely important to notice that COPD patients
have a permanent restriction breathing air out. This is different from asthmatics
who will have episodes with airway obstruction, but will have perfectly normal
flow volume curves between attacks. Among the COPD group of patients there are
two major groups represented, the chronic bronchitis patient
and the emphysema patient.Chronic bronchitis
COPD patient: When the bronchial tubes are chronically damaged,
the patient will have COPD of the chronic bronchitis type. For a patient to be
diagnosed with this condition requires that the patient has a chronic cough ("smokers'
cough") and coughs up phlegm and mucous for at least 3 months
in a year for at least two concecutive years and airway obstruction can be diagnosed
using spirometry. Clinically these patients present as "blue
bloaters". Emphysema COPD patient: When
the small air sacs (alveoli) are damaged, the patient will have COPD of the emphysema
type ("pink
puffer"). However, there are often overlaps where both chronic
bronchitis and emphysema are present and these patients are usually the ones with
the most severe form of COPD. Chronic asthmatic bronchitis COPD:
There is a minority of cases where the patient never smoked,
but had a chronic and difficult to control asthma for many years, and this type
of patient can deteriorate into a COPD, which is irreversible. They have a different
pattern on spirometry than the other forms and the respirologist can identify
and treat such patients. Using spirometry the patient's COPD can further
be classified into mild,
moderate or severe COPD as is explained in this link. Some
statistics on COPD: COPD is the 4th most common cause of
death and accounts for 4.5% of all deaths in the US. About 15 million people
suffer from COPD in the US and about 17 million office visits are due to this
lung disease. Although smoking is the most common cause of COPD, only 15% of smokers
get COPD as there seems to be a susceptibility in certain people more so than
others to develop it. COPD severity is directly linked to the amount and years
of exposure to cigarette smoke. Passive smoking can also lead to COPD, but is
usually less severe (Ref. 1, p. 678). Males have been affected much more than
females with COPD due to the smoking statistics in the past. However, since females
are now outnumbering male smokers in the US, the statistics are also turning around
and COPD in women is getting much more common. Signs and symptoms: COPD
presents itself usually in a person of 50 years or older with a 20 year or longer
history of having been exposed to heavy cigarette consumption (more than 20 years
of at least one pack per day). The patient's main complaints are difficulties
in breathing (=dyspnea), coughing up pussy mucous and periods of wheezing. The
mucous is coughed up mainly in the morning, has a grey color to it and is also
occasionally coughed up during the rest of the day. The patient with emphysema
has hardly any mucous production, but has dyspnea with wheezing. If blood is coughed
up (=hemoptysis), this usually comes from chronic bronchitis or associated pneumonia.
Lung cancer must also be ruled out. Patients with severe COPD likely will have
symptoms of being very tired, complaining of a lack of memory, of confusion and
depression. There may also be weight loss and loss of appetite because of the
chronicity of the illness. If swelling of the connective tissues (=edema) is present,
this would be a pointer to a possible right sided heart failure due to pulmonary
hypertension. This condition is called "cor
pulmonale" and is a serious sign of impending deterioration
of the chronic lung disease. The physician suddenly faces a patient with both
a lung and a heart condition. Diagnostic tests: The
history of breathing problems with a careful questioning of the symptoms will
tell the physician already quite a lot about the COPD patient. Clinically there
often is a swelling of the fingers with "watch glass nails" or clubbing.
This bulbous swelling of the finger's distal portion develops as a result of chronic
oxygen deficit in the tissues of the fingers and can also occur in the toes.
This is complemented by the clinical examination and by spirometry testing. Chest-rays
likely are also ordered to diagnose the absence or presence of signs of severe
lung emphysema. High resolution CT scan is useful in delineating emphysema, particularly,
if there are small bubbles (=medically termed "bullae") as is shown
in this link. An electrocardiogram is also done to rule out a strain on the right
heart, which would indicate some degree of pulmonary hypertension from the chronic
lung problem. A coughed up mucous sample (=sputum) is sent to the lab for Gram
staining and possibly culture and sensitivity testing, if pussy. Other blood tests
may be ordered by the specialist to rule out allergic cells (=eosinophils)
or to check for inborn enzyme deficiencies, which are rare (alpha-1
antitrypsin deficiency), but not infrequently seen among COPD sufferers.
Treatment:
Medications: The pharmacological treatment of COPD
involves the proper administration of medication utililising the metered
dose inhaler . With this delivery system the medications necessary
to open the airways can be delivered with reliability and accuracy. See this link
for dosages and medication types. The American
Lung Associationhas published this COPD fact sheet (see link) that
contains a lot of useful information as well. Many COPD patients have to take
corticosteroids by mouth and inhale higher doses of it as well. In patients with
chronic bronchitis COPD prophylactic antibiotics may have to be taken on an ogoing
basis such as trimethoprim-sulfamethoxazole. Theophylline may also have to be
added and blood levels would have to be monitored from time to time as described
under asthma. It is advisable for the patient to attend a multidisciplinary
pulmonary disease rehabilitation clinic to learn all about the various
therapy steps that need to be done in concert. Vaccinations: Vaccination
against the flu every fall season and against pneumococcal
infections every 5 to 6 years has been shown to be effective in preventing further
deterioration and to prevent many premature deaths from COPD. Oxygen
therapy: Oxygen therapy on a 24-hour basis is recommended
for chronic cases who are still deficient when oxygen in the blood is measured
despite optimal therapy with medication. Dr. Lindsay Lawson (Ref. 10) pointed
out that oxygen delivery to the tissues is determined by two factors, namely cardiac
output and oxygen content of the blood. This explains why any heart disease that
interferes with the pump activity of the heart will reduce tissue oxygen supply.
On the other hand any problem with oxygen saturation of the blood such as anemia
or slightly reduced oxygen pressure (high mountains, travel by airplane) will
also reduce oxygen delivery to the tissues. Normally healthy people have no problem
adjusting to the slightly reduced oxygen pressure in airplanes as the heart can
automatically beat slightly faster to deliver oxygen to the tissues. However,
in severe COPD patients this slight change of oxygen concentration in the air
makes a profound difference as the oxygen saturation in the blood can be reduced
by 2 to 3 %. The biophysics of oxygen
dissociation curves is explained in this link in detail for those
who would like to delve into this complicated topic. These facts are behind the
need for chronic COPD patients for a continuous oxygen supply. Your family doctor
can prescribe the exact oxygen concentration that such a patient needs. A baseline
arterial blood gas test and possibly some other tests (spirometry, blood tests
for hemoglobin concentration etc.) have to be done first. Funding agencies will
require these tests as well. Oxygen is delivered by portable cannisters and plastic
tubes and/or by mask. Like other medications oxygen has side effects as well.
Oxygen from a tank or cannister has 0% humidity, which explains why nasal irritation
from drying out mucous membranes and nasal discharge can be a problem. Sinus infections
and congestions are also common. These side effects are dose dependent and one
should always use as little oxygen as possible to get therapeutic effect. Surgery
for severe COPD cases: For areas of severe involvement,
particularly if bronchiectasis
or emphysema is present, resection of a particularly bad affected area by a chest
surgeon may be feasible. In patients with congenital lung enzyme defect a lung
transplant on one lung may be prolonging life significantly. In the COPD of cystic
fibrosis patients a heart and lung transplant may be needed. All of this would
be extensively discussed with the specialists involved and the heart condition
would have to be stable enough to allow such invasive procedures.
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