Differentiating COPD from Asthma | Jindal Chest Clinic

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DIFFERENTIATING COPD FROM ASTHMA

• Dr. S. K. Jindal
• www.jindalchest.com

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What is COPD?

• Chronic bronchitis and emphysema
• Bronchial asthma
• Asthmatic bronchitis
• Nonspecific airway obstruction

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Burden of COPD in Various Indian Studies
Jindal et al. IJCDAS 2001, IJCDAS 2006
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Risk factors for COPD
Adjusted OR (95 CI)
Gender Men 1.000
Women 1.056 (0.897-1.224)
Age 35-44 years 1.000
45-54 years 1.552 (1.325-1.816)
55-64 years 2.174 (1.839-2.570)
65-74 years 4.102 (3.464-4.858)
gt75 years 4.899 (3.953-6.070)
Usual residence Rural 1.000
Urban 1.224 (1.083-1.384)
Mixed 1.563 (1.139-2.143)
Socioeconomic status Low 1.000
Middle 0.717 (0.632-0.814)
High 0.675 (0.536-0.850)
Smoking habit Nonsmoker 1.000
Cigarette smoker 1.952 (1.578-2.416)
Bidi smoker 2.654 (2.292-3.074)
Hookah smoker 2.897 (2.044-4.106)
Cooking fuel No self cooking 1.000
Cooking with LPG 0.781 (0.629-0.968)
Cooking with kerosene 1.252 (0.889-1.763)
Cooking with solid fuels 0.995 (0.787-1.258)
Jindal et al. IJCDAS 2006
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Misdiagnosis is Frequent !

• Many times patients are incorrectly labeled
• Genuine difficulty in diagnosis, due to overlap
  of symptoms of COPD and asthma
• Lack of awareness of differences between these
  two disease conditions
• More often, patients with COPD are labeled
• as having asthma

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Remember

• All that wheezes is not asthma
• All smokers with respiratory symptoms do not have
  COPD
• Asthma COPD are not the same disease
• No single rule of thumb to differentiate

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COPD is not Asthma

• Different causes
• Different inflammatory cells
• Different mediators
• Different inflammatory consequences
• Different sites
• Different response to treatment

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Question 1

• How is airway inflammation in COPD different from
  that in asthma ?
• Predominant macrophages
• IL-4 and IL-5 involvement
• Epithelial shedding
• Mucosal fibrosis

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Inflammation
Asthma COPD
Inflammatory cells Mast cell, Eosinophil Neutrophil
CD4 cells CD8 cells
Macrophages Macrophages
Inflammatory LTB4, histamine LTB4
mediators IL-4, IL-5, IL-13 TNF-a
Oxidative stress Oxidative stress
Inflammatory effect All airways Peripheral airways
AHR AHR
Epithelial shedding Epithelial metaplasia
Fibrosis Fibrosis
No parenchymal involvement Parenchymal destruction
Mucus secretion Mucus secretion
Response to steroid
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Inflammation

• But clinicians have no means to assess these
  differences in inflammation
• For proper diagnosis, they must rely on
• History
• Physical examination
• Simple investigations

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Question 2

• How does a good history and a thorough
• physical examination help to distinguish
• COPD from asthma?
• Identification of triggers
• Progressive course
• Episodic nature
• Audible wheezes

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History
Asthma COPD
Onset Variable more often Usually later in life
in childhood / early (4th to 5th decade)
adulthood
Course Episodic Progressive
Smoking Uncommon Common
Nasal symptoms Common Rare
Atopy Common Rare
Family history Often Uncommon
Triggers Often identified None
Wheeze Prominent almost May or may not be
universal present
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Physical Examination

• Resting hyperinflation is a hallmark of
  emphysema, and conventionally seen in asthma
  only during acute attacks
• Complications such as cor pulmonale, chronic
  respiratory failure, etc. are seen in advanced
  COPD, and virtually never in bronchial asthma

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Question 3

• Which is the best laboratory investigation in
  differentiating COPD from asthma?
• Haemogram Eosinophils
• CXR
• PEF
• Spirometry

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Investigations
Asthma COPD
Chest radiograph Normal Suggestive
Spirometry Obstructive defect Obstructive defect
Good reversibility Poor reversibility
AHR Very common May be present
DLCO Normal / Increased Decreased
Lung elastic recoil Normal Increased
Thoracic CT scan Airway wall thickening Airway wall thickening
Mucus plugs (ABPA) Emphysema
Air trapping Air trapping
In general, investigations are poor discriminators
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Question 4

• Based on history, physical examination, and
  common investigations, how well can one
  distinguish COPD from asthma?

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The Diagnosis !

• Based on the complete clinical profile, it is
  easy under most circumstances to comment whether
  a given patient is more likely to have COPD or
  asthma
• Some patients may be really difficult to
  diagnose due to overlap of clinical and
  pathophysiological features

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The Overlap !
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Take Home Message

• Important for clinicians to
• understand that asthma and COPD are two entirely
  different disorders
• appreciate that clinical judgement has a far
  greater role than investigations in
  differentiating COPD from asthma

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THANK YOU