Interstitial Lung Disease Flashcards
A high resolution CT scan of the thorax would show what in patients with interstitial lung disease?
“ground glass” appearance
What can be said about the prognosis of interstitial lung disease?
poor prognosis
irreversible damage
treatment is supportive rather than curative
What are some of the ways that restrictive lung conditions can be managed?
5
- smoking cessation
- pulmonary rehab
- LTOT (hypoxic at rest)
- pneumococcal and flu vaccine
- remove or treat underlying cause
What are some of the causes of pulmonary fibrosis?
3
- idiopathic
- drug induced
- secondary (to other conditions)
How does pulmonary fibrosis often present?
- patients >50
- dyspnoea
- dry cough >3 months
During examination of patient with pulmonary fibrosis, what clinical findings might be found?
- bibasal fine inspiratory crackles
- finger clubbing
- cyanosis
What is the prognosis of pulmonary fibrosis?
poor
2-5 year life exp. from diagnosis
Which medications have been known to cause drug-induced pulmonary fibrosis?
4
- amiodarone
- nitrofurantoin
- methotrexate
- cyclophpsphamide
Secondary pulmonary fibrosis may be brought about from which pre-existing conditions?
4
- alpha-1 antitrypsin deficiency
- rheumatoid arthritis
- lupus
- sclerosis
If the cause of the pulmonary fibrosis is not usual interstitial pneumonitis, what might be the cause?
hypersensitivity pneumonitis
What is hypersensitivity pneumonitis?
Type III hypersensitivity reaction to environmental allergen
How does hypersensitivity pneumonitis present?
- dry cough
- fever, myalgia
- crackles, tachypnoea, wheeze
- chills 4-9hrs after exposure to allergen
- precipitating antibody
What is the response to the allergens inhaled?
granulomatous response
raised lymphocytes/mast cells
What are some examples of specific causes of hypersensitivity pneumonitis (EAA)?
4
- bird droppings
- farmers lung (mouldy spores in hay)
- mushroom workers lung
- malt workers lung (mould in barley)
Which part of the lung is often affected by hypersensitivity pneumonitis?
upper zone
Most usual interstitial pneumonitis are either idiopathic or __________.
cryptogenic
What is cryptogenic organising pneumonia?
How is it triggered?
Focal area of inflammation of the lung tissue - very similar presentation to infectious pneumonia.
Triggers:
- infection
- idiopathic
- inflammatory disorders
- medication
- radiation
- allergens
How is cryptogenic organising pneumonia treated?
corticosteroids
What is honeycombing of the lung?
It is the attempted repair of fibrosis, it physically looks like honeycomb.
What can inhalation of asbestos lead to?
asbestosis - may take decades to present
What does asbestosis cause in the lungs?
fibrosis (it is fibrogenic)
cancer (it is also oncogenic)
What are the main problems which asbestos inhalation can lead to?
4
- lung fibrosis
- pleural thickening and pleural plaques
- adenocarcinoma
- mesothelioma
What would be the spirometry findings in a patient with interstitial lung disease?
FEFV1: reduced
FVC: reduced
FEV1:FVC - normal or low
Why? - not as much air is entering the lung to begin with
What is characteristic of Type 1 respiratory failure?
Why?
PaO2 low
PaCO2 normal or low
PaO2 is low due to reduced diffusion (e.g. fibrosis)
PaCO2 is normal as Co2 is much more soluble than O2 and is less affected
How is a fall in PaO2 due to hypoventilation corrected?
O2 therapy with increased FIO2
What is the normal V/Q ratio?
0.8 (around 1)
What is the most common cause of hypoxaemia?
low V/Q (i.e. low ventilation)
