Obstructive Lung Disease Flashcards
What are the two types of restrictive lung disease?
What is the pathology behind each type?
Restrictive lung diseases: impaired total lung function: Extrinsic OR Intrisic
Intrinsic: pathology arises from lung parenchyma inflammation and scarring. Causes redued alveolar function & alveolar gas transfer
Extrinsic: pathology arises from abnormal function of chest wall, pleura & neuromuscular apparatus. Causes impaired ventilator function &
respiratory failure
What is intrinsic restrictive lung disease caused by? [1]
Name two pathologies that cause extrinsic restrictive lung disease caused by? [2]
Intrinsic: Interstitial Lung Diseases
Extrinsic: Obesity & Myasthenia Gravis (rare long-term condition that causes muscle weakness)
What are the two major interstitial lung diseases? [2]
Idiopathic Pulmonary Fibrosis
Sarcoidosis
Describe the aetiology of IPF xx
Describe the pathophysiology of IPF
Occurs due to:Unknown cause [1]
Environmental factors, chronic viral infections, smoking, Fx causes scarring and honeycombing of the lungs: airway remodelling. Causes impaired oxygen transfer.
Airway remodelling cccurs due to:
- fibroblast remodelling and activation: causes fibroblast plaques occurring & collagen deposition. Causes Traction bronchiectasis: where there is irreversible dilatation of bronchi and bronchioles within areas of pulmonary fibrosis
- ↓ Epithelial cell integrity
- Accelerated ageing-associated changes
- Exaggerated fibroblast expansion
Describe symptoms of IPF [3]
- exertional dyspnoea
- clubbing
- dry cough
What would the lung sound like on physical examination of a Ptx with IPF? [1]
Fine, high-pitched bibasilar inspiratory crackles (velcro-like sounds
What is the key diagnostic test for identificaiton of IPF?
How do you calculate this?
DLCO (Diffusing capacity of the lungs for CO): measures the quantity of carbon monoxide (CO) transferred per minute from alveolar gas to red blood cells (mL/min/mm Hg)
DLCO = Lung surface area available for gas exchange (Va) X rate of capillary blood CO uptake (Kco)
(Kco is particularly affected by IPF)
Describe the diagnostic pathway for IPF xx
- Suspected ILD
- ID the cause? If yes - not IPF
- If no, conduct Chest High Resolution CT Scan. If you see usual interstitial pneumonia (honeycombing lungs) then v likely to have IPF.
Still unsure? - Lung biopsy
- MDT Diagnosis
- IPF / Not IPF
Which drugs would you use to manage IPF ? [3]
How would you treat IPF via non-pharmacotherapy?
Pharmacotherapy:
- Pirfenidone: anti fibrotic agent, decreases pyhysiological deterioration
- Nintedanib : Tyrosine kinase inhibitor. ↓FVC decline
- Antiacid therapy:IPF with gastro-oesophageal reflux
Non-pharmacotherapy:
- Pulmonary rehab (MDT Team & QoL
- Oxygen therapy
- Lung treatment
Which drugs should you NOT combine to treat IPF?
Prednisone, Azathioprine & NAC = Harmful AEs
Treatment pathway for IPF?
What FVC and DLCO would you continue pharmalogical treatment of IPF?
What drug would you use?
Treat using Pirfenidone if:
FVC less than 10%
and
DLCO less than 15%
IF WORSE - assess Pirfenidone use - use with NAC instead? Clinical trials?
What would a Ptx’s FVC and DLCO be to start pharmalogical treatment of IPF?
Mild - moderate disease:
FVC greater than 50%
DCLO greater than 35%
Define sarcoidosis
Caused by multi system granulomas (is a tiny cluster of white blood cells and other tissue that can be found in the lungs). Inflammation causes multi-system granulomas
Most cases are acute, self-limiting (needs no medicinal treatment)
About 90% of diagnosed cases are deemed to be pulmonary sarcoidosis.
Idea of physiopathology causing sarcoidosis?
Unknown BUT:
Antigen (bacteria?) phagocytosed by antigen-presenting cells
Presentation of antigen to T cells by HLA class II molecules
Formation of sarcoid granuloma
How do you diagnose sarcoidosis? (probably dont need to know)
Clinicoradiographic data / CXR:
- Bilateral hilar adenopathy on the chest radiograph
- Lofgren syndrome (erythema nodosum skin rash + bilateral hilar adenopathy on chest radiograph +/- fever and arthritis)
What pharmacological treatment consider for sarcoidosis?
Treat with corticosteroids (but has negative impact on immune system).
Remember than patients may have spontaneous resolution so have to weigh up options !!
Explain MoA of corticosteroids
- A patient inhales an ICS, and it arrives at the lungs
- It crosses the cytoplasm and binds to the glucocorticoid receptors (GR) - the GR is the endogenous receptor that mediates the actions of ICS
- The now activated GR translocate from the cytoplasm, into the nucleus where it may bind to glucocorticoid response elements (GRE) which leads to increased gene expression of anti-inflammatory genes. These are genes that code proteins that fight against inflammation.
Alternatively, the activated GR may recruit transcriptional machinery and proteins that leads to downregulation of gene expression of pro-inflammatory mediators
