Restrictive lung disease Flashcards
Define restrictive lung disease
Reduced lung volumes (TLC, FRC and FVC)
These conditions cause trouble when fully expanding lung
Describe parenchymal lung disease.
Which four conditions cause restriction in the parenchyma?
Transient problems of alveoli filling processes (water, blood, pus etc)
- Pulmonary oedema
- Pulmonary haemorrhage
- Infection (e.g. pneumonia)
- Infiltrative cancer
Describe the types of interstitial disease (connective tissue) that can occur
Intralobular septa- surround individual alveoli where capillaries are found
Interlobular septa- outline the secondary lobes. This is where the lymphatics & veins of the lungs are
Usually not seen by CT, only when expanded by blood/pus etc
Thickened septa may be caused by left heart failure or lymphangtic spread of cancer
Normal interstitial structures can be affected by inflammation or fibrotic scarring
Outline the causes of interstitial lung disease
Environmental exposure
- Hypersensitivity pneumovitus (e.g. mould and bird protein)
- Occupational (e.g coal, silica, asbestos) PERMANENT PARTICLES
Idiopathic
- Vasculitis
- Idiopathic pulmonary fibrosis
- Lymphangioleiomyomatosis (LAM)
Systemic inflammatory disease
- Autoimmune disease- ILD (rh.arthiritis)
- Sarcoidosis (granulomatous)
Describe the pathophysiology of occupational interstitial lung disease, specifically coal.
Small coal dust particles reach air sac (Lasts forever in lung)
Engulfed by macrophages= inflammation
may trigger massive fibrosis
May lead to progressive lung fibrosis
What kind of disease does silica and coal dust cause?
Nodular disease is common
Areas of dense fibrosis
What does asbestos exposure look like on a CT?
Fine peripheral lines on CT
'’Honeycomb cysts”
Can also cause pleural plaques (calcified) which can turn into mesothelioma tumours
Describe what happens in hypersensitivity pneumonitis
Antigen-presenting cell expresses antigen on MHC complex
T cell becomes sensitised to antigen
Stimulates macrophages activation which leads to granuloma formation
Also causes inflammation along bronchioles and alveoli
Can be acute (weeks) or chronic, fibrotic teases which could lasts months/years. The fibrosis occurs as the body attempts to repair the problem
Describe a typical patient who might present with Idiopathic pulmonary fibrosis
What does the disease look like?
> 50, smoker or previous smoker
Mostly affects the lower and peripheral aspects of long
Fine peripheral lines
Honeycomb cysts
Lots of fibroblasts which make collagen type 3 which is not helpful n stretching, minimal inflammation
IT IS PROGRESSIVE
What is atelectasis?
Describe the different kinds
Incomplete expansion as alveolar are not able to fill with air properly
- Resorptive atelectasis endobronchial obstruction –> Dwindling alveolar size –> Eventual lung collapse
- Compressive atelactasis: pleural process or lung mass causes loss of transmural distending pressure promoting alveolar expansion (It is in this way that effusions cause restriction)
Can occur as a result of post-op pain –> less ventilation–> prone to alveolar collapse
Describe the normal contents of the pleural space.
Normally 1L of fluid cycles through pleural space/day
(At any one time scant/radiologically undetectable amount in pleural space)
It lubricates pleural surface
What is a pleural effusion?
Effusion occur when influx of fluid> efflux
It is the abnormal accumulation of >25ml
Influx comes from:
- Capillary leak
- Pulmonary interstitium
- Small holes in diaphragm allowing peritoneal fluid to enter the pleural space. E.G ascites(more common on RHS)
Efflux:
Lymphatics: resorptive stoma give the pleura large surge capacity (can increase absorption 20x)
What are the symptoms of pleural effusion?
What does it look like on a CXR?
In effusion, patient complaints of dyspnoea, dullness to percussion
Fuzzy diaphragm borders
What are the causes of pleural effusion?
- Congestive heart disease
- Liver disease with portal hypertension and cirrhosis
- Low albumin states (e.g nephrotic syndrome)
- Infection (TB, parapneumonia, empyema)
- Malignant cancer
- Sterile inflammation/autoimmune: pleurisy
- Chylothorax
A pleural effusion can either be described as transudate or exudate. Describe each.
TRANSUDATE
Most common
Imbalance in hydrostatic/oncotic capillary pressures
Not harmful, dyspnoea
Caused by non-pleural disease primary process
Resolved if primary process fixed
SOMETHING WRONG WITH NORMAL FLUID BALANCE
EXUDATE Will not resolve alone (drain) Needle aspiration OR (chest) tube thoracotomy Caused by primary pleural disease Varies by subtype SOMETHING WRONG WITH PLEURA
