Obstructive Lung Diseases

Question 1

Answer 1

Question 2

Definition of Asthma

Answer 2

• Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role, in particular, mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, and epithelial cells.
• In susceptible individuals, this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness and coughing, particularly at night or in the early morning.
• These episodes are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment.
• The inflammation also causes an associated increase in the existing bronchial responsiveness to a variety of stimuli.

Question 3

Asthma Pathogenesis

Answer 3

• classic view: T-helper-type-2 cell dependent IgE associated allergic disease
• multiple phenotypes/endotypes

Extrinsic vs Intrinsic

Atopic vs Nonatopic

TH2high vs TH2low

Type2 vs Non-type2

Eosinophilic vs Non-eosinophilic

Question 4

Two Forms of Eosinophilic Asthma

Answer 4

• allergic eosinophilic airway inflammation
• nonallergic eosinophilic airway inflammation

Question 5

Hygiene Hypothesis

Answer 5

Increased hygiene and cleanliness and/or the widespread use of antibiotics and immunizations may deprive the developing immune system of environmental cues shaped by evolution to skew adaptive immunity away from Th2 responses.ypothesis

Question 6

Inciting Factors for Asthma

Answer 6

• Allergens
• Infections

– Viral Respiratory Infections

• Air Pollution
• Occupational Exposures
• Exercise
• Cold Air
• Drugs

– Aspirin, NSAIDs

• Emotions

Question 7

Diagnosis of Asthma

Answer 7

• Symptoms

– Wheeze, cough, dyspnea, chest tightness

• Exam

– May be normal between attacks

– Chest

• Expiratory > inspiratory wheeze
• Prolonged expiratory time
• Hyperinflation
• Accessory muscle use
• Spirometry

Question 8

Deifinition of COPD

Answer 8

• COPD is a disease state characterized by airflow limitation that is not fully reversible.
• The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases, primarily caused by cigarette smoking.

Question 9

Alpha-1 Antitrypsin Deficiency

Answer 9

• Most common genetic cause of emphysema (2-3% of patients)
• SERPINA1 gene encodes alpha-1 antitrypsin (AAT)

—protease inhibitor

– Autosomal inheritance; normal allele termed “M”

– Multiple abnormal alleles identified but most common severe deficiency—”Z” allele

– Low levels and severe emphysema with ZZ genotype

– Slight reduced levels with MZ genotype—unclear risk for emphysema

• Suspect if:

– Emphysema at young age (<45 years)

– Nonsmoker

– Bibasilar disease (panlobular emphysema vs upper lobe predominant centrilobular with smoking)

– Chronic liver disease

– Family history emphysema or liver disease

Question 10

Clinical Features of COPD

Answer 10

• Typically smokers – mean 20 cigarettes/day for 20 years
• Usually present in fifth or sixth decade of life
• Progressive dyspnea with exertion and cough
• Often first diagnosed after an acute chest illness
• History of wheezing and dyspnea may lead to misclassification and a diagnosis of asthma
• Exam

– Prolonged expiratory phase

– Hyperinflation (hyperresonant to percussion; increased A-P diameter of chest)

– Decreased breath sounds

– Wheezes, especially with forced expiration

– Crackles may be heard at posterior lung bases

– No clubbing

Question 11

Differential Diagnosis of COPD

Answer 11

• Other broncho-pulmonary diseases

– e.g., asthma, bronchiectasis

• Congestive heart failure
• Ischemic heart disease
• Valvular heart disease
• Pulmonary embolism
• Pulmonary hypertension

Question 12

In asthma, the predominant inflammatory cell is the […] and in COPD the […].

Answer 12

In asthma, the predominant inflammatory cell is the eosinophil and in COPD the neutrophil.

This difference in inflammatory cell type is important in the therapeutic response to corticosteroids between asthma and COPD.