Obstructive Airway Diseases Flashcards by Rassa Kapite

What are the obstructive airway diseases?

Chronic bronchitis
Emphysema
Asthma

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What are chronic bronchitis and emphysema known as?

COPD

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What is FEV1?

Forced expiratory volume of air exiting the lung in the first second

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What is FVC?

Final total amount expired

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FEV vs FVC

FEV1 usually about 70 - 80% of FVC
FEV 1 - 3.5 - 4 litres
FVC - 5 litres

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Normal FEV1:FVC ratio

0.7- 0.8

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What is predicted FVC based on?

Age
Sex
Height

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What does PEFR stand for?

Peak expiratory flow rate

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What is PEFR used to monitor at home?

Bronchial asthmatics respiratory function

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Normal PEFR

400 - 600 L/min

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Normal range of PEFR

80 - 100% of best value

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What is a moderate fall of PEFR?

50 - 80%

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What is a marked fall of PEFR?

< 50%

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Features of obstructive lung disease

Airflow limitation
PEFR reduced
FEV1 reduced
FVC reduced
FEV1 less than 70% of FVC

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Pathology of bronchial asthma

Type 1 hypersensitivity in the airway
Allergic (associated) reactions
Constriction of bronchial smooth muscle
Inflammation response

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What type of obstruction is bronchial asthma? In response to what?

Reversible
In response to
- spontaneously
- pharmacological intervention

Causes of chronic bronchitis / emphysema

Any chronic irritant being inhaled into the lungs
Smoking
Atmospheric pollution
Occupation (dust)
Alpha 1 antiprotease (antitrypsin) deficiency (emphysema)

Which gender gets chronic bronchitis /emphysema?

M > F

Definition of chronic bronchitis

Cough productive of sputum most days in at least 3 consecutive months for 2 or more consecutive years

What does chronic bronchitis result in?

Natural decline in FEV1

What is complicated bronchitis?

Mucopurulent (mucus and pus) in an acute infective exacerbation
FEV1 falls

Morphological changes in chronic bronchitis

Large airways
- mucous gland hyperplasia
- goblet cells hyperplasia
- inflammation and fibrosis
Smaller airways
- goblet cells appear
- inflammation and fibrosis in long standing disease

Definition of emphysema

Increase beyond the normal size of the airspaces distal to the terminal bronchiole arising either from dilation or from destruction of their walls and without obvious fibrosis

What is the terminal bronchiole?

Last conducting airway of sub mm in size which is completely lined by respiratory epithelium

Pathology of emphysema

Increase in size of airspaces distal to terminal bronchiole Loss of alveolar tissue (making spaces bigger) Loss of alveolar walls may take place in the acinus

What is the acinus?

The region of the lung supplied with air from one of the terminal bronchioles

Types of emphysema

Centriacinar Paracinar Periacinar Bullous

What is centriacinar emphysema?

Begins with bronchiolar dilatation Gough wentworth section of the lung Upper regions of the lung

What is paracinar emphysema?

Lower regions of the lung Massive destruction All gas tissue disappears and left with tubes and airways suspended in space

What is periacinar emphysema?

Enlarged air spaces along the edge of the acinar unit but only where it abuts against a fixed structure such as pleura or a vessel

What is a bulla?

Emphysematous space greater than 1cm

What is used to describe bullae under the pleura?

Bleb

Causes of emphysema

Smoking Ageing Alpha - 1 - antitrypsin deficiency

Pathology of smoking causing emphysema

Protease : antiprotease imbalance Leads to malfunction of alpha 1 antitrypsin and similar enzymes Causes inflammation in the lungs which also causes damage These enzymes try to repair the damaged tissue but they cant so the tissue damage occurs and stays

Most important factor in the pathology of emphysema

Loss of alveolar attachments

Causes of respiratory alkalosis

PE Anxiety leading to hyperventilation CNS disorders e.g. stroke, SAH, encephalitis Altitude Pregnancy

Causes of respiratory acidosis

COPD Opiate overdose Life threating decompensated asthma NM disease Obesity hypoventilation syndrome Benzodiazepines overdose