19 - Benign lung pathology

What 3 factors about the nature of tubes affect the conduction of air into the lungs?

1) Lumen size

2) Wall strength

3) Wall support

What affects the rate of diffusion across alveolar walls?

- Difference in partial pressure

- Surface area

- Thickness of walls

- V/Q ratio

Inflammation in the lungs can have what 2 functionally depleting consequences?

1) Tissue loss

2) Fibrosis

What respiratory condition is characterised by the loss of lung tissue?

Emphysema

What respiratory condition is characterised by the fibrosis of lung tissue?

Chronic interstitial lung disease

What is asthma?

Reversible intermittent narrowing of conducting airways due to inflammation

Is asthma obstructive or restrictive?

Obstructive

What is the epidemiology of asthma?

- Children and young adults (atopic): allergic

- Adults (non-atopic): non-allergic

What triggers asthma?

- Allergens

- NSAIDs

- Cold

- Exercise

- Infections

- Emotions

What is the pathology of asthma?

- Inflammation and so thickening of bronchiole walls

- Smooth muscle contraction so lumen narrowing

- Mucus

What are the symptoms of asthma?

- Dyspnoea

- Wheeze

- Cough

- Hyperinflation

What is the short-term treatment for asthma?

- SABAs: salbutamol

- Anticholinergics: ipratropium

- Corticosteroids: prednisone, methylprednisone

What do anticholinergics do for asthma?

Prevents bronchiconstriction

What is the long-term treatment for asthma?

- Inhaled corticosteroids: budesonide, beclomethasone

- LABA: salmeterol

- Leukotriene receptor antagonists: montelukast

- Methylxanthines: theophylline

What do methylxanthines do for asthma?

Cause bronchidilation

What is bronchitis?

Inflammation of the bronchi with increased goblet cells and so mucus production

What is COPD?

A combination of chronic bronchitis and emphysema

What is the aetiology of COPD?

- Smoking (90%)

- Environment (toxins & pollutants)

- Genetics (alpha1-antitrypsin deficiency)

What is the pathology of COPD?

- Chemicals and heat induce inflammation in bronchi and lung parenchyma

- Causes inflammation, fibrosis and mucus hyperplasia as well as emphysema

What is bronchiectasis?

Permanent dilation of bronchi and bronchioles secondary to chronic necrotising infection

What is the aetiology of bronchiectasis?

- Obstruction

- Infection

Is bronchiectasis obstructive or restrictive?

Obstructive

What is the pathology of bronchiectasis?

Obstruction causes infection inducing inflammation with dilation

What are the symptoms of bronchiectasis?

- Productive cough

- Haemoptysis

- Repeat infections

What is chronic interstitial lung disease?

Scarring and inflammation of the lung which reduces compliance

Is ILD obstructive or restrictive?

Restrictive

What are the common types of ILD?

- Idiopathic pulmonary fibrosis (IPF)

- Pneumoconiosis

- Sarcoid

- Hypersensitivity pneumonitis (HP)

What is idiopathic pulmonary fibrosis?

- Idiopathic progressive patchy interstitial fibrosis in lower lung which is fatal

What is the epidemiology of IPF?

- M>F

- >60 years old

What are the symptoms of IPF?

- Dry cough

- Dyspnoea

What is pneumoconiosis?

Lung damage secondary to particle inhalation - usually coal, dust, silica from mining, asbestos from occupational exposure

What is the epidemiology of pneumoconiosis?

- Mainly male due to occupational exposure

What is the aetiology of pneumoconiosis?

Chronic particle inhalation

What is the pathology of pneumoconiosis?

Particles are ingested by macrophages triggering fibrosis

What is sarcoid?

Multisystem granulomatous disease that involves lymph nodes and lungs

What is the epidemiology of sarcoid?

- 20-60 years old most common

- M=F

- African or Northern European

- Non-smokers

What is the aetiology of sarcoid?

Idiopathic

What is the pathology of sarcoid?

Granulomatous inflammation causing fibrosis

What are the symptoms of sarcoid?

- Nodal enlargement

- Cough

- Dyspnoea

- Fever

- Fatigue

- Weight loss

- Sweats

What is cystic fibrosis?

Disorder of cell membrane causing thickened mucus production

Is cystic fibrosis obstructive or restrictive?

Obstructive

What is the aetiology of cystic fibrosis?

- Autosomal recessive of CFTR gene

What is the pathology of cystic fibrosis?

- Reduced sodium and chlorine in the lumen of respiratory tract, GI tract and seminiferous tubules

- Causes dehydrated mucus which is thicker and blocks lumen

What are the symptoms of cystic fibrosis?

- Chronic cough

- Persistent lung infections

- Malabsorption

- Eventually right sided heart failure

What is the treatment for cystic fibrosis?

- Mucolytics: pulmozyme

- Bronchodilators: albuterol

- Ivacaftor

- PERT: pancreatic enzyme replacement therapy

- Fat soluble vitamin replacement: A, D, E, K