COPD is a progressive lung disease characterized by breathlessness and airflow limitation. It affects over 174 million people globally as of 2015. The main risk factors for COPD include smoking tobacco, exposure to indoor and outdoor air pollution, and genetic conditions. While COPD has no cure, treatment can help manage symptoms and slow progression. Exacerbations, or sudden worsening of COPD symptoms, are usually caused by respiratory infections and exposure to environmental pollutants. Exacerbations can be prevented by reducing risk factors and treated through medications and pulmonary rehabilitation.

1. COPD
DR C B DHANRAJ

2. EPIDEMIOLOGY
• As of 2015, COPD affected about 174.5 million people (2.4% of the
global population).[7]
• It typically occurs in males and females over the age of 35–40.[1][3] In
2019 it caused 3.2 million deaths, 80% occurring in lower and middle
income countries,[3] up from 2.4 million deaths in 1990.[22][23]
• The number of deaths is projected to increase further because of
continued exposure to risk factors and an aging population.

3. • Chronic obstructive pulmonary disease (COPD) is a type of
progressive lung disease characterized by long-term respiratory
symptoms and airflow limitation.[8]
• The main symptoms of COPD include shortness of breath and
a cough, which may or may not produce mucus.[4] COPD progressively
worsens, with everyday activities such as walking or dressing
becoming difficult.[3]
• While COPD is incurable, it is preventable and treatable.

4. • Emphysema is defined as enlarged airspaces (alveoli)
whose walls have broken down resulting in permanent damage to
the lung tissue. Chronic bronchitis is defined as a productive cough
that is present for at least three months each year for two years. Both
of these conditions can exist without airflow limitation when they are
not classed as COPD.

5. • Many definitions of COPD in the past included emphysema and
chronic bronchitis, but these have never been included in GOLD
report definitions.[8] Emphysema and chronic bronchitis remain the
predominant phenotypes of COPD but there is often overlap between
them and a number of other phenotypes have also been
described.[9][13] .[12

6. • COPD and asthma may coexist and converge in some
individuals.[14] COPD is associated with low-grade systemic
inflammation.[15]
• The most common cause of COPD is tobacco smoking.[16] Other risk
factors include indoor and outdoor air pollution including dust,
exposure to occupational irritants such as dust from grains, cadmium
dust or fumes, and genetics, such as alpha-1 antitrypsin deficiency

7. • In developing countries, common sources of indoor air pollution are
the use of coal and biomass such as wood and dry dung as fuel
for cooking and heating.[18][12] The diagnosis is based on poor airflow
as measured by spirometry.[4]

8. • Most cases of COPD can be prevented by reducing exposure to risk
factors such as smoking and indoor and outdoor pollutants.[19] While
treatment can slow worsening, there is no conclusive evidence that
any medications can change the long-term decline in lung
function.[6] COPD treatments include smoking
cessation, vaccinations, pulmonary
rehabilitation, inhaled bronchodilators and corticosteroids.[6]

12. Exacerbations
An acute exacerbation is a sudden worsening of signs and symptoms that lasts for
several days. The key symptom is increased breathlessness, other more
pronounced symptoms are of excessive mucus, increased cough and wheeze. A
commonly found sign is air trapping giving a difficulty in complete exhalation.[30] The
usual cause of an exacerbation is a viral infection, most often the common
cold.[12] The common cold is usually associated with the winter months but can
occur at any time.[31] Other respiratory infections may be bacterial or in combination
sometimes secondary to a viral infection.[32] The most common bacterial infection is
caused by Haemophilus influenzae.[33] Other risks include exposure to tobacco
smoke (active and passive) and environmental pollutants – both indoor and
outdoor.[34] During the COVID-19 pandemic, hospital admissions for COPD
exacerbations sharply decreased which may be attributable to reduction of
emissions and cleaner air.[35] There has also been a marked decrease in the
number of cold and flu infections during this time.[36]

14. Smoke from wildfires is proving an increasing risk in many parts
of the world and government agencies have published protective
advice on their websites. In the US the EPA advises that the use
of dust masks do not give protection from the fine particles
in wildfires and instead advise the use of well-fitting particulate
masks.[37] This same advice is offered in Canada to the effects of
their forest fires.[38] Bushfires in Australia add to the high risk
factors for COPD and its worsening for farmers.[39]

15. The number of exacerbations is not seen to relate to any stage of
the disease; those with two or more a year are classed
as frequent exacerbators and these lead to a worsening in the
disease progression.[30] Frailty in ageing increases exacerbations
and hospitalization.[40]
Acute exacerbations in COPD are often unexplained and thought
to have many causes other than infections. A study has
emphasized the possibility of a pulmonary embolism as
sometimes being responsible in these cases. Signs can
include pleuritic chest pain and heart failure without signs of
infection. Such emboli could respond to anticoagulants.[41]