Respiratory Flashcards
How many generations of airways from trachea to alveoli?
How many have cartilage support?
23 generations total
16 have cartilage
What is the gene involved in AAT deficiency?
Which alleles are highest risk for cirrhosis?
Which are highest risk for emphysema?
Gene is called SERPINA1 on chromosome 14
Usually occurs in those homozygous for Z or M(malton) alleles
ZZ homozygotes ot ‘null’ alleles
What is the mechanism of COPD development in AAT deficiency?
Results from imbalance between neutrophil elastase in lung, and AAT
- Increased elastase burden
- Increased destruction of elastin
- Lung proteolytic degradation
What is the function of alpha-1 trypsin?
AAT is a protease inhibitor, which inhibits elastase.
Thus deficiency leads to excessive elastin destruction
What is “Samter’s Triad” in AERD?
Nasal polyps, asthma, and sensitivity to aspirin
What is the main substance implicated in AERD?
Leukotrienes
What does high FENO indicate?
Predicts response to ICS
Measure of eosinophilic inflammation
What is the most effective strategy to halt progress in COPD?
Smoking cessation
What are the 3 interventions in COPD with mortality benefit?
Smoking cessation
Long term O2 therapy if meeting criteria
Transplant / lung reduction surgery
PaO2 cut offs for home O2?
PaO2 <55 PaO2 <60 in - RHF - Pulmonary HTN - Secondary polycythaemia
Most common side effect of ICS?
Hoarse voice
Most common bacterial cause of COPD exacerbation?
Haemophilus influenzae
What is the BODE Index?
Predictor of mortality in COPD
B - BMI low
O - Obstruction (FEV1)
D - Dyspnoea score
E - exercise tolerance
MOst common genetic mutation in Type 1 pulm HTN?
Bone morphogenetic protein receptor type 2 (BMPR2) mutations
Most common genetic mutation in Type 1 pulm HTN?
Bone morphogenetic protein receptor type 2 (BMPR2) mutations
What is the most common genetic mutation in CF?
Delta F508
What does the CFTR protein do when functioning normally?
CFTR protein functions mainly as a chloride channel
- also regulates activity of other chloride and sodium channels on cell surface
- Active at the apical membrane of epithelial cells
- Regulates movement of sodium and water across cell membrane
What are the mechanisms of hypoxia which will give a raised A-a gradient?
V/Q mismatch
Shunt
Diffusion abnormality
What is the equation for A-a gradient calculation?
[150 - (PaCO2 x 1.25)] - PaO2
What is a normal A-a gradient?
Should be around Age/4 + 4
What are the mechanisms of hypoxia which will give a normal A-a gradient?
Hypoventilation
Low FiO2
What are the two main mechanisms for hypercapnia?
Decreased minute ventilation
Increased dead space
What are the 2 main mechanisms for decreased minute ventilation?
“can’t breathe” - decreased respiratory drive
“won’t breathe” - decreased nerve / muscle function, or thoracic cage limitation
What is the criteria for obstruction on PFTs?
FER <0.7
What is the criteria for reversibility of obstruction on PFTs?
Improvement of >12% and >200ml in FEV1 or FVC
What causes reduced DLCO in absence of significant restriction or obstruction?
Pulmonary vascular disease (e.g. thromboembolic disease, pulmonary HTN)
When are MIP / MEP useful to measure in PFTs?
To evaluate for respiratory muscle weakness
What is the 12 month mortality after an exacerbation of COPD requiring admission?
25%
What is the PBS criteria for triple therapy in COPD?
FEV1< 50 and history of repeated exacerbations with significant symptoms despite dual therapy
What is the biological therapy option for severe allergic asthma?
Omalizumab
- IgE mab
What is the biological therapy option for severe eosinophilic asthma?
Mepolizumab
- anti-IL 5 ab
What are the classic pathological features of Usual Interstitial Pneumonia (IPF)?
Honeycombing
Traction bronchiectasis
Reticular opacities
What is nintedanib?
Common SE?
Anti-fibrotic for IPF
Multi-kinase inhibitor
SE: diarrhoea
What is pirfenidone?
Anti-fibrotic for IPF
Inhibits TGF-beta and fibroblast proliferation
What are the classic pathological features of Non-specific Interstitial Pneumonia?
Ground glass opacity
Traction bronchiectasis
Reticular opacities
Which immune cells are key to sarcoidosis pathogenesis?
Th1 cells
What is the leading cause of pulmonary HTN worldwide?
Schistosomiasis
What class of drugs are ambrisentan, macitentan, bosentan?
How do they work?
Endothelin receptor antagonists
Work to block endothelin receptor, which inhibits vasoconstriction
Which 2 medication classes should NOT be used in combination in pulmonary HTN?
sGC stimulators (Riociguat) + PDE5 inhibitors - increased risk of hypotension and death
What is the role of azithromycin in bronchiectasis?
For patients with 3 or more exacerbations per year
Dosing 500mg 3x / week
Anti-inflammatory, reduces exacerbation frequency
Where is the brain centre for inspiration?
Dorsal medullary centre
Where is pulmonary surfactant produced?
Type 2 alveolar epithelial cells
3 ILD conditions linked to smokng?
Respiratory bronchiolitis - associated
Desquamative
Langerhans histiocytosis
Main site of airway resistance in lungs?
Medium-sized bronchioles
What causes NSIP pattern (~4)
CTD
HIV
Drugs
Hypersensitivity
What is Light’s criteria?
If at least one of the following three criteria is fulfilled, the fluid is defined as an exudate:
- Pleural fluid protein/serum protein ratio >0.5
- Pleural fluid LDH/serum LDH ratio >0.6
- Pleural fluid LDH greater than 2/3 the upper limits of the laboratory’s normal serum LDH
What are pleural fluid tumour markers for mesothelioma?
Mesothelin
Fibulin 3
What are 3 common presentations of adult-diagnosed CF?
GI symptoms
Diabetes
Infertility
