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.
Thoracentesis
Procedure that involves using a needle to sample or drain a pleural effusion.
No more than 1.5L of fluid should be drained to avoid re-expansion pulmonary oedema.
Studies of pleural effusion fluid
pH
Cell counts
Microbial stain + culture studies
Cytopathology- identification of cancer cells
Protein, LDH, glucose and cholesterol levels.
Triglyceride levels
Light’s criteria for determining exudative effusion
Effusion is exudative IF:
Protein levels in pleura/ Protein levels in serum > 0.5
Lactate dehydrogenase level in pleural / LDH level in serum > 0.6
LDH in pleura > 2/3 upper limit of normal in serum.
Empyema
Infection in pleural cavity which causes collection of pus in the cavity.
Requires complete evacuation to prevent development of fibrous visceral pleural peel —> leads to a trapper lung.
Parapneumonic effusion
Effusion caused by pneumonia.
Indications:
Sterile inflammation
pH> 7.2
Small, free flowing fluid.
This effusion usually heals as the pneumonia heals.
Haemothorax
Blood in pleural cavity
Indications:
Pleural fluid hematocrit> 50% of blood HCT.
Requires complete evacuation to prevent development of fibrous visceral pleural peel —> leads to a trapper lung.
Hepatic hydrothorax
Occur when cirrhotic fluid transverses across the diaphragm, via rents, into the pleural space.
Chylothorax
Pleural effusion where triglyceride levels are greater than 110 mg/dL in the pleural fluid.
Triglycerides drain from cisternal cyli, via thoracic duct.
Spontaneous pneumothorax
Collection of air in the pleural cavity.
This is causes by formation of small air sacs (blebs) which rupture and leak air into the pleural space.
Traumatic pneumothorax
Collection of excess air in the pleural space caused by trauma that is: Penetrating Procedural Pressure (barotrauma) Ribe fracture.
Weakness and myopathic chest wall diseases
Degenerative spinal disease
Myasthenia gravis
Global weakness- muscle weakness
Degenerative spinal disease
Conditions that affect the chest wall structure and can cause restrictive lung disease:
Motor neurone disease
Polio
Myasthenia gravis
Serious skeletal muscle weakness
This causes chest wall disease that implicates ventilation- restrictive lung disease
Skeletal and connective tissue restrictions that cause chest wall diseases
Kyphoscoliosis
Extensive burns around the chest wall.
Kyphoscoliosis
Abnormal curving of the spine at both the coronal and sagittal plane.
This distorts the chest wall and causes restrictive lung disease.
