Lecture 10: Restrictive lung disease Flashcards
Reductions in which lung volumes defines restriction?
RV, FRC and TLC
What do intralobular septa do?
Surround the alveoli, and are a thin layer between the alveoli and capillaries
What do interlobular septa do?
Outline the secondary lobules
Where the lymphatics and veins of the lungs are
What is an interstitial lung disease?
Diseases which cause inflammation or scarring of the interstitium of the lung
What are the two types of environmental exposure interstitial disease?
Allergic responses that affect the interstitium:
- Hypersensitivity pneumonitis
- Occupational lung disease, aka pneumoconioses
What may cause hypersensitivity pneumonitis?
Mould and bird proteins are the common causes
What are the main causes for occupational lung disease?
Coal miners lung (coal dust exposure)
Silicosis (silica exposure)
Asbestosis (asbestos exposure)
What are the three categories of ILD?
1: environmental exposure
2: idiopathic
3: systemic inflammatory
What are the two types of inflammatory disease?
Autoimmune disease - ILD
Sarcoidosis
What coal miners lung?
Very small coal dust particles reach airsacs
Engulfed by macrophages inflammation
Sometimes trigger massive fibrosis
Coal dust essentially lasts forever in the lung
What are the three lung diseases that are associated with asbestos?
Asbestosis
Mesothelioma
Lung cancer
What is the importance of pleural plaques in the lung?
The plaque wont turn into mesothelioma but is indicative of exposure to asbestos
What is mesothelioma?
Aggressive, fatal, occurs at high rate
What causes fine peripheral lines +/- “honeycomb” cysts
Asbestos
What exposure causes nodular disease?
Silica and coal dust
What is a granuloma?
Clusters of macrophages (with a few T cells typically in the periphery)
What is the mechanism behind hypersensitivity pneumonitis?
Patients breathes something in (mould), picked up by APC, recognised by T cell, creates inflammatory response, form granuloma with T cells on the outside
Granulomas build up in the bronchiole
What conditions can lead to fibrosis?
Hypersensitivity pneumonitis
What is idiopathic pulmonary fibrosis?
Disease of older age (rare before age 50)
Most patients have smoked, but the disease process is not well understood: “idiopathic”
Mostly affects the lower + peripheral aspects of the lung
Fine peripheral lines + honeycomb cysts
Lots of fibroblast cells (make collagen)
Minimal inflammation
What are the alveolar filling processes?
Pulmonary oedema
Pulmonary hemorrhage
Infection (ie pneumonia)
Cancer
What is resorptive atelectasis?
Collapse of (otherwise healthy) alveoli
As a result of dwindling alveolar size - eventually lung collapse
What is compressive atelectasis?
Collapse of (otherwise healthy) alveoli
As result of pleural process or lung mass
What are the two types of pneumothorax?
Spontaneous
Traumatic: procedural, penetrating trauma, rib fracture, baurotrauma
What are the three types of pleural disease?
PE
Pneumothorax
Haemothorax
What volume of liquid normally cycles through the pleural space?
1L
What causes influx of fluid into the pleural space?
Capillary leak (increased hydrostatic pressure or loss of oncotic pressure)
Pulmonary interstitium (crosses the visceral pleura)
Small holes, or “rents”, in the diaphragm allowing peritoneal fluid (if any is accumulating) to enter the pleural space
What causes efflux of fluid into the pleural space?
Lymphatics: resorptive stoma give the pleura large surge capacity (can increase absorption 20x), but if these become blocked (even partially) absorption will slow
Resorption is dependent on good oncotic pressure within lymphatics
What are the causes of transudative PE?
Congestive heart failure
Liver disease with portal hypertension and cirrhosis
Low albumin states (eg. nephrotic syndrome)
What are the causes of exudative PE?
Infection
- TB
- Acute bacterial infection: “parapneumonic” effusion or empyema
- Parasitic infection
Malignant (metastatic cancer)
Chylothorax
Pleurisy
What is the difference between transudate and exudate?
Transudate = leakage of water (doesn’t need to be drained)
Exudate = Leakage of water and proteins (needs to be drained)
What is transudative effusion?
Most common
Generally not harmful to patient, although can cause dyspnoea when large
The result of a non-pleural disease primary process
Will resolve if primary process is fixed
(Something wrong with normal fluid balance)
What is uncomplicated parapnuemonic effusion?
Altered (pleural) capillary permeability in pneumonia (vasodilatory effect of inflammation)
Effusion with increased inflammatory cells but no bugs
Drain by tap if effusion is not small
What is complicated parapnuemonic effusion?
Increased inflammatory cells with bacteria in the pleural space
Not frank pus, but the increased inflammation with bacteria needs to be drained by tube otherwise a pleural rind can form
This rind MUST be surgically removed (if left, it will decrease pleural expansion and lead to permanent restriction in that part of the lung)
What is empyema?
Frank pus
Needs to be fully drained, usually over several days, with a chest tube
What is chylothorax?
Due to retrograde spillage of lymphatic materials (which includes lots of fats which have have been absorbed from the GI tract) into pleural space
Most commonly this is due to thoracic duct injury
What is the definition of haemothorax?
When haematocrit value of at least 50% of the haematocrit of peripheral blood
What is pleurisy?
Sterile process of inflammatory cells and fluid accumulating in the pleural space due to autoimmune disease
What is a thoracentesis?
Procedure using a needle to sample or drain the effusion
How do you prevent re-expansion pulmonary oedema?
Limit drainage to 1.5L/day
How do you diagnose exudative effusion?
Light’s criteria
If one or more of the following criteria are met:
• Protein level in pleural fluid divided by level in serum is greater than 0.5
• Lactate dehydrogenase (LDH) level in pleural fluid divided by level in serum is greater than 0.6
• LDH in pleural fluid is more than two-thirds the upper limit of the normal level in serum
What are the fluid studies?
Protein and LDH
pH and glucose
Cell counts with WBC differential
Microbial stain and culture studies
Cytopathology to evaluate for cancer cells
Cholesterol levels and triglyceride (TG) levels
Less common: adenosine deaminase (ADA), RF titer, lupus erythematosus cells
How do you diagnose hepatic hydrothorax?
Cirrhotic fluid transverses the diaphragm into the pleural space
How do you diagnose parapneumonic effusion (complicated)?
Infected pleural space, pH < 7.2
Loculations can form
How do you diagnose parapneumonic effusion (uncomplicated)?
Sterile inflammation
pH > 7.2
Small / free flowing
How do you diagnose haemothorax?
Pleural fluid Hct > 50% of blood Hct
How do you diagnose cylothorax?
TG > 110 mg/dL
Usually appears milky
What is pneumothorax?
Pneumothorax: air collection in the pleural space due to rupture of alveoli near pleural surface
Spontaneous pneumothorax
Swings in intrapleural pressure and blebs are often invoked
Traumatic pneumothorax: procedural, penetrating trauma, rib fracture, baurotrauma
What are the causes of chest wall disease?
Weakness and myopathy
Skeletal and connective tissue restrictions
What are the different types of weakness and myopathy?
Degenerative spinal diseases; eg. motor neurone disease; polio
Myasthenia gravis
Global weakness
What are the causes of skeletal and connective tissue restrictions?
Kyphoscoliosis
Extensive burns which affect the chest wall
