Week 5 - Restrictive and Obstructive Lung Disease Flashcards
4
What does TLCO measure?
Measures how well oxygen and carbon dioxide are transferred between the alveoli (air sacs) and the blood in the pulmonary capillaries
How does KCO differ from TLCO?
KCO is TLCO that is adjusted for alveolar volume - i.e. measures the transfer of CO in alveoli that are ventilated.
Both are reduced by V/Q mismatch conditions.
KCO is not diminished by extra thoracic restrictive conditions -whereas TLCO is - therefore helps you distinguish the cause.
Why does the FEV1:FVC ratio increase in restrictive lung disease?
Restrictive lung disease - lungs are smaller - therefore FVC decreases, but less than FEV1 - therefore ration increases.
What can cause restriction to the lungs?
Damage to the parenchyma (inflammation and fibrosis) - e.g. pulmonary fibrosis, sarcoidosis, pneumoconiosis
Pleural disease (P Eff, pneumo/haemothorax, calcification, mesothelioma)
Obesity
Chest wall disease (NMD, palsy, kyphosis/scoliosis)
In lung fibrosis - where is the primary site of injury?
The interstitium - between the cells and basement membrane - thickens and stiffens = reduced transfer of O2
What are the RF for lung fibrosis?
How can Sx for lung fibrosis present?
SOB - worsening progressively
Cough
Fatigue
Weight loss
Crackles
How can you differentiate an AI cause for lung fibrosis?
AI / Collagen vascular - can also have difficulty swallowing, cold hands, joint pains, weight loss, skin rash
What are the clinical signs of lung fibrosis?
Clinical signs à ↑ RR, Tachypnoea, Dyspnoea, Clubbing, CVS - ↑ JVP, perip oedema, loud P2 heat (signs of cor pulmonale). Low O2 sats – desats on exertion.
If AI can have – RA, skin changes (telangiectasia, Raynaud’s), joint signs, eye signs
What is it called when we dont know what is causing fibrosis of the lungs?
Idiopathic pulmonary fibrosis (IPF)
M>F
What is the average length of surivival from diagnosis of IPF?
2.5-3.5 years
Often sudden exacerbation (infection) & decline – dramatic decrease in LF à death
What does honeycombing and bronchial dilation on CT suggest?
IPF
What does spirometry show in IPF?
What Rx is given for IPF?
Symptomatic
Antifibrotic
Palliative (if young poss transplant)
What investigations can you do to investigate whether a P has pulmonary fibrosis or not?
Bloods - FBCs, U&Es, AI screen
CXR
HRCT
Spirometry
TLCO and KCO
What type of respiratory failure is caused by pulmonary fibrosis?
T1
Which type of pulmonary fibrosis is associated with AI or collagen vascular disease?
Non-Specific Interstitial Pneumonia
(is actually pneumonitis not a pneumonia)
How does NSIP differ from IPF in terms of Ps?
Younger Ps affected
Not associated with smoking
M = F (whereas in IPF - M>F)