CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

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CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)


Chronic obstructive pulmonary disease (COPD) is defined as a disease state characterized by airflow limitation that is not fully reversible (http://www.goldcopd.com/). It is the third leading cause of death worldwide, causing 3.23 million deaths in 2019. It is more prominent in low and middle-income countries. 

It basically includes 2 diseases, Emphysema, and Chronic bronchitis.

CAUSES AND RISK FACTORS:
  1. Cigarette smoking - Subsequent longitudinal studies have shown an accelerated decline in FEV1 in a dose-response relationship to the intensity of cigarette smoking, which is typically expressed as pack-years.
  2. Hyperresponsiveness of alveoli - A tendency for increased bronchoconstriction in response to a variety of exogenous stimuli, including methacholine and histamine, is one of the defining features of asthma. Dutch hypothesis suggests that asthma, chronic bronchitis, and emphysema are variations of the same basic disease, which is modulated by environmental and genetic factors to produce these pathologically distinct entities.
  3. Frequent Cold
  4. Respiratory infections
  5. Occupational Exposure - Increased respiratory symptoms and airflow obstruction have been suggested to result from exposure to dust and fumes at work.
  6. Air pollution - Some investigators have reported increased respiratory symptoms in those living in urban compared to rural areas, which may relate to increased pollution in the urban settings.
  7. Genetic Predisposition - Severe α1 AT deficiency is a proven genetic risk factor for COPD; there is increasing evidence that other genetic determinants also exist.

SYMPTOMS:

The three most common symptoms in COPD are cough, sputum production, and exertional dyspnea. Patients may also develop resting hypoxemia and require the institution of supplemental oxygen.

PHYSICAL FINDINGS:-

In the early stages of COPD, patients usually have an entirely normal physical examination. In patients with more severe disease, the physical examination is notable for a prolonged expiratory phase and may include expiratory wheezing. In addition, signs of hyperinflation include a barrel chest and enlarged lung volumes with poor diaphragmatic excursion as assessed by percussion.

Patients with severe airflow obstruction may also exhibit the use of accessory muscles of respiration, sitting in the characteristic “tripod” position to facilitate the actions of the sternocleidomastoid, scalene, and intercostal muscles. Patients may develop cyanosis, visible in the lips and nail beds. Although traditional teaching is that patients with predominant emphysema, termed “pink puffers,” are thin and noncyanotic at rest and have prominent use of accessory muscles, patients with chronic bronchitis are more likely to be heavy and cyanotic (“blue bloaters”).

Advanced disease may be accompanied by cachexia, with significant weight loss, bitemporal wasting, and diffuse loss of subcutaneous adipose tissue.

Some patients with advanced disease have paradoxical inward movement of the rib cage with inspiration (Hoover’s sign), the result of an alteration of the vector of diaphragmatic contraction on the rib cage as a result of chronic hyperinflation.


PATHOGENESIS:

The dominant paradigm of the pathogenesis of emphysema comprises four interrelated events:

(1) Chronic exposure to cigarette smoke leads to inflammatory and immune cell recruitment within the terminal air spaces of the lung. 

(2) These inflammatory cells release elastolytic and other proteinases that damage the extracellular matrix of the lung. 

(3) Structural cell death (endothelial and epithelial cells) occurs directly through oxidant-induced cigarette smoke damage and senescence as well as indirectly via proteolytic loss of matrix attachment. 

(4) Ineffective repair of elastin and other extracellular matrix components results in air space enlargement that defines pulmonary emphysema.

DIAGNOSIS: 


1) CLINICAL BLOOD ANALYSIS:

Arterial blood gases and oximetry may demonstrate resting or exertional hypoxemia. 

An elevated hematocrit suggests the presence of chronic hypoxemia, as does the presence of signs of right ventricular hypertrophy.


2) SPIROGRAPHIC TEST:

Pulmonary function testing shows airflow obstruction with a reduction in FEV1 and FEV1 /FVC (Chap. 306e). With worsening disease severity, lung volumes may increase, resulting in an increase in total lung capacity, functional residual capacity, and residual volume.


3) CHEST X-RAY:

Radiographic studies may assist in the classification of the type of COPD. Obvious bullae, paucity of parenchymal markings, or hyper-lucency suggest the presence of emphysema. Increased lung volumes and flattening of the diaphragm suggest hyperinflation but do not provide information about the chronicity of the changes.


TREATMENT:

PHARMACOTHERAPY:- 

- Bronchodilators In general, bronchodilators are used for symptomatic benefit in patients with COPD.

- Anticholinergic Agents Ipratropium bromide improves symptoms and produces acute improvement in FEV1.

- Beta Agonists - These provide symptomatic benefit. The main side effects are tremors and tachycardia. Long-acting inhaled β agonists, such as salmeterol or formoterol,

- Inhaled glucocorticoids

- Oral Glucocorticoids - The chronic use of oral glucocorticoids for treatment of COPD is not recommended because of an unfavorable benefit/risk ratio. The chronic use of oral glucocorticoids is associated with significant side effects, including osteoporosis, weight gain, cataracts, glucose intolerance, and increased risk of infection.

- Theophylline- Theophylline produces modest improvements in expiratory flow rates and vital capacity and a slight improvement in arterial oxygen and carbon dioxide 

- Antibiotics - Early trials of prophylactic or suppressive antibiotics, given either seasonally or year-round, failed to show a positive impact on exacerbation occurrence.

- Oxygen Supplemental- O2 is the only pharmacologic therapy demonstrated to unequivocally decrease mortality rates in patients with COPD.


REFERENCES:

1) CHEST X-RAY COPD. (n.d.). [PHOTOGRAPH]. https://prod-images-static.radiopaedia.org/images/266487/d35992af9e42aba7d71001c13843c3_thumb.jpg

2) CHRONIC OBSTRUCTIVE PULMONARY DISEASE. (n.d.). [PHOTOGRAPH]. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRZ13Q3v71KdGoYlJp-R-dHpbK1SY3hh5NNZQ&usqp=CAU

3) Chronic obstructive pulmonary disease (COPD). (2021, June 22). Who.Int. https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd)

4) COPD: CAUSES AND RISK FACTORS. (2018). [PHOTOGRAPH]. https://www.verywellhealth.com/thmb/KpdL1SRVVbURs2tfL6Be7dnS6jI=/614x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/copd-causes-57-5aeca0f4a9d4f90037e4ce96.png

5) Fauci, A. S., MD, Hauser, S. L., MD, Longo, D. L., MD, Jameson, L. J., MD, & Kasper, D. L., MD. (2015). Harrison’s Principles of Internal Medicine (19th ed.). McGraw-Hill Professional Pub.

6) GETTING DIAGNOSED WITH COPD. (n.d.). [PHOTOGRAPH]. https://www.templehealth.org/sites/default/files/inline-images/copd-diagnostic-tests.png

7) SIGNS AND SYMPTOMS OF COPD. (n.d.). [PHOTOGRAPH]. https://www.ttsh.com.sg/PublishingImages/Lists/ListFCCondition/AllItems/COPD%201.png

8) TREATMENT OF COPD. (n.d.). [PHOTOGRAPH]. https://www.verywellhealth.com/thmb/R12bBr8oC-YGrvzTMehSJVGy61g=/614x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/treatment-for-severe-copd-914817-v1-5c4e413bc9e77c00014afb39.png



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