| What can interstital lung disease lead to | Leads to temporary or permanent changes in the interstitial tissues (development of fibrosis tissue)
Interfere gas exchange
Change mechanics of breathing
Stiff lungs - The development of fibrous tissue in the interstitium, makes lungs less compliant, to produce a 'restrictive' ventilatory defect |
| What is a interstitum | The 'interstitial space' is a potential space between alveolar cells and the capillary basement membrane, which is only apparent in disease states, when it may contain fibrous tissue, cells or fluid
Structures between the alveoli and capillaries |
| What are some investigations which can be used | Chest X-ray
Lung Function Test
In difficult cases, surgical lung biopsy might be necessary |
| What would you find on examination of patient with interstital lung disease | Cyanosis
Tachycardia
Tachypnea
Finger Clubbing ( important in Pulmonary Fibrosis )
Fine end inspiratory crackles
Signs of right heart failure such as peripheral oedema |
| What is the presentation of interstital lung disease | Progressive breathlessness with reduced exercise tolerance
Dry cough
Extra-pulmonary symptoms --> Fever, joint pain and lethargy etc. |
| What are the easy to remember inorganic inhaled dust | Asbestos
Silicates
Carbon ( Coal dust ) |
| What is the pathophysiology of asbestos | Asbestos fibres breathed in and lodge in distal air spaces ( less than 7mm )
Scavenged by macrophages
This can lead to pleural plaques, benign pleural effusion and diffuse pleuritic thickening
It can also be cardiogenic causing mesothelioma and broncho-carcinoma |
| What is Fibrosing Alveolitis | Progressive inflammatory condition in which the cause in unknown --> idiopathic
Pathogenesis is also unclear but histologically there is high number of macrophages hence could be an infection or pollutant
WBC cause damage to the alveoli by releasing proteases which leads to tissue destruction and fibrosis
Finger clubbing is present in this disease |
| What is an Extrinsic Allergic Alveolitis | Term used for a number of conditions in which the inhalation of an organic material triggeres a diffuse allergic reaction in the walls of alveoli and bronchioles
E.g. Farmers Lung due to exposure to an antigen from Thermophillic Actinomyocyetes |
| How can you differentiate between Extrinsic Allergic Alveolitis and Fibrosing Alveolitis | There is no finger clubbing in Extrinsic Allergic Alveolitis |
| What is hypersensitivity Pneumonitis | Caused by inhalation of variety of organic or inorganic antigens trigger a complex immune response
Alveolar walls thickened and infiltrated with immune cells
Lymphocytes and occasionally eosinophils |
| What is the difference between acute and chronic form of hypersenstivity pneumonitis | Acute form :
Produces dry cough and breathlessness on exertion
CXR findings – micro-nodularity denser towards the hilar
Chronic form :
Long-term exposure to antigens over months or years
malaise (feeling persistently unwell) dry cough and breathlessness
CXR findings → normal but may progress to pulmonary fibrosis affecting upper zones |
| What are some investigations for HP | Lung biopsy --> if everything is not working
Bronchoalveolar levage which has evidence of lymphocytosis ( greater than 20% is diagnostic ) |
| What can be used to distinguish between Sarcoidosis and TB/lymphoma | Characteristics features is the presence of non-caseating granuloma on a biopsy
Used to distinguish between TB and lymphoma |
| What might you see in investigations of sarcoidosis | Obstructive or restrictive patterns in lung functioning tests
ACE serum level raised
Hypercalcaemia |
| What are Idiopathic Interstitial Lung Disease | Inflammation of interstitial tissues of unknown cause |
| Pathophysiology of IPF | Cause is unknown
Progressive inflammatory condition of the lung
Histologically there is evidence of increased numbers of activated alveolar macrophages
Activated macrophages attract neutrophils and eosinophils which produce local lung damage by generation of reactive oxidant species and proteases. This results in tissue destruction and fibrosis |
| What are the different causes of pleural effusion | Excess fluid in pleural space
Hydrostatic pressure increases in capillaries – Heart failure
Permeability of capillaries increases – Inflammation, malignancy
Oncotic pressure decreases - hypoproteinaemia |
| What is the meaning of Empyema and Chylothorax | Empyema --> Pus
Chylothorax --> Chyle |
| What are the causes of transudate and exudate pleural fluid | Transudate → cardiac failure, liver failure, renal failure
Exudate → Cancer, infection or connective tissue disease |
| What are pleural plaques | Benign areas of thickening → post asbestos exposure
Usually asymptomatic patients |
| What are some congenital chest wall diseases | Pectus carinatum is a protrusion deformity of the anterior chest wall ( pigeon chest )
Pectus excavatum (funnel chest ) is a deformity of the chest wall characterized by a sternal depression
Scoliosis → abnormal lateral curvature of the spine
Kyphosis → Abnormal excessive forward curvature of the spine |
