Restrictive lung disease Flashcards
Restrictive lung diseases
Pulmonary conditions that reduces lung volumes:
TLC
FRC
FVC
Conditions prevent the lung from expanding to normal volumes.
Lung interstitium
The interstitial space- between cells.
Intralobular- location of the capillaries which surround alveoli.
Interlobular- surround secondary lobules. Location of lymphatics and veins.
Interstitial lung disease
Condition characterised by abnormal interstitium due to:
Inflammation
Scarring
There causes:
Environmental exposure
Idiopathic
System inflammatory diseases
Environmental exposure causes of ILD
Hypersensitivity pneumonitis
Occupational lung disease
Hypersensitivity pneumonitis
A type of ILD causes by the lungs having an excessive immune response to mould or bird proteins, usually.
APCs present the particles and activates T cells.
T cells activate macrophages to form granulomas and also inflames the bronchioles and intralobular septa.
Occupational lung disease
Also called pneumoconiosis
A type of ILD caused by exposure to specific substances associated with certain occupations:
Silicosis- silica exposure
Coal miners lung- coal dust exposure
Asbestosis- asbestos exposure.
Silicosis
Pneumoconiosis caused by excess inhalation of silica.
This causes nodular fibrosis - progressive massive fibrosis
Asbestosis
Pneumoconiosis caused by inhalation of asbestos.
The asbestos fibres form honeycomb cysts which can be seen on CT scans.
Pleural plaques can occur and turn into mesothelioma tumours.
Idiopathic pulmonary fibrosis (IPF)
A common ILD
Usually present in older people, over 50.
Commonly seen in individuals who have smoked, but the mechanism is still not understood.
Forms honeycomb cysts seen in CT scans and affects the lower and peripheral aspects of the lungs.
There isn’t that much inflammation, instead there are many fibroblasts that makes XS collagen- type III.
Resorptive atelectasis
Collapse of alveoli due to endobronchial obstruction.
Air becomes trapped inside the alveoli- when left too long, the gases are absorbed into the blood.
This deflates the alveoli, due to the loss of its distending pressure.
Compressive atelectasis
Alveoli collapse due to the formation of a pleural process or lung mass.
This pushes the lung, forcing it to collapse.
Systemic inflammatory diseases that cause ILD
Autoimmune disease ILD
Sarcoidosis
Coal miner’s lung
A type of pneumoconiosis cause by coat dust particle inhalation.
The particles are very fine and enter alveoli, where they are engulfed by macrophages.
This triggers inflammation which can can trigger massive fibrosis.
Coal dust stays in the lung forever.
Pleural effusion
IL of fluid cycles the pleural cavity every day.
When the fluid is >25mL, this is a pleural effusion.
This occurs when influx of fluid exceeds efflux of fluid.
Influx of pleural fluid
Methods in which pleural fluid enters the pleural space:
Capillary leak- high HP/ very low oncotic pressure
Fluid from pulmonary interstitium crosses visceral pleura.
Peritoneal fluid enters via rents in the diaphragm into pleural space.
Efflux of pleural fluid
Method of pleural fluid leaving the pleural space:
Resorptive stoma in the pleura allows fluid to drain into lymphatics.
Percussion of a chest with pleural effusion
This will show dullness at the base due to fluid filling the base of the lung.
Causes of pleural effusion
Congestive heart failure
Liver disease with portal HT and cirrhosis
Low albumin states- nephrotic syndrome
Infections: TB, empyema, parasites
Malignancies
Pleurisy
Cylothorax
Transudative effusion
Most common type of pleural effusion where fluid is mainly water.
It usually arises from a non-pleural disease process.
The effusion will resolve if primary problem is fixed
Exudative effusion
A pleural effusion that contains protein rich fluid in the pleural space.
This will not resolve itself, so always needs to be drained.
Conditions that cause altered pleural membrane permeability leading to exudative pleural effusions.
Infection
Cancer
Autoimmune disease
Conditions that cause altered capillary membrane permeability leading to exudative pleural effusions.
Pneumonia- has a vasodilatory effect
Mechanisms of exudative effusions
Entry of tumour cells via lymphatics- cancer
Thoracic duct injury- spills lymphatic material into pleural space.
Penetrating trauma- causes blood in the pleural space
Tube thoracostomy
Placement of a chest tube to usually drain a exudate pleural effusion.
