Submitted by: Submitted by damlexy
Views: 10
Words: 692
Pages: 3
Category: Other Topics
Date Submitted: 10/25/2015 10:34 AM
2
PATHOPHYSIOLOGY OF LUNG DISEASE
2.1
Introduction
Diseases that affect lung function cause one of two patterns of dysfunction –
‘obstructive’ and ‘restrictive’. Obstructive diseases include diseases characterised by a
reduction in airflow and airflow limitation including asthma, chronic bronchitis, chronic
obstructive pulmonary disease (COPD) and emphysema. Restrictive lung diseases are
characterised by a reduction in lung size or an increase in lung stiffness resulting in a
decrease in the maximum volume of air that is able to be moved in and out of the lungs
e.g. pulmonary fibrosis, asbestosis. Restrictive disorders may also occur as a result of
mechanical abnormalities such as respiratory muscle weakness (neuromuscular
disorders) and abnormalities of the chest wall (e.g. kyphoscolisis, thoracic wall
deformity). Other systemic diseases are also known to affect the function of the lung
including rheumatoid arthritis, congestive heart failure, and scleroderma. Furthermore,
certain commonly used drugs are known to cause abnormalities within the lung e.g.
methotrexate, amiodarone.
These two patterns of lung dysfunction may arise from one of five main abnormalities:
• Respiratory disorders e.g. fibrosis, oedema, congestive heart failure (CHF),
pleural disease, resection, emphysema
• Airway disease e.g. asthma, COPD
• Pleural cavity e.g. effusion, enlarged heart, tumour
• Chest wall e.g. scleroderma, ascites, pregnancy, obesity, kyphoscoliosis
• Muscle disorders e.g. neuromuscular disease, polio, diaphragmatic paralysis
Figure 2.1
Classification of respiratory disorders
CHEST
WALL
LUNG
Airflow Obstruction
Fibrosis
Tumour
Resection
Atelectasis
Scleroderma
Kyphoscoliosis
Pregnancy
Obesity
Ascites
MUSCLE
Polio
Neuromuscular Disease
Diaphragmatic
Paralysis
THORACIC
CAVITY
Tumour
Enlarged Heart
Effusion
27
2.2
Obstructive Lung Disorders
Obstructive diseases of the lung are extremely common and second only to heart
disease as a cause of disability, with...