at 2 - Physiology in Clinical Practice Flashcards
What is asthma?
chronic inflammatory disorder of the airways leading to airflow obstruction
Describe the appearance of a peak flow trace when its:
- normal
- obstructive
- restrictive
Normal = increases linearly, then plateaus Obstructive = shallow gradient, can't blow out as quickly as possible but can blow out the same volume of air if given the time to do so. FEV1/FVC
How is asthma diagnosed?
> 12% incerase in FEV1 post bronchodilator
or >20% in PEFR diurnal variability
- also can test for airway hyperresponsiveness, given drugs to induce this and spirometry performed
Describe the pathogenesis of asthma.
Allergen activates dendritic cells, activate a Th2 lymphocyte cascade
B cells release IgE
Mast cells release inflamarotry mediators and leukotrienes
Other inflammatory cells are stimulated
eosinophils also attracted to lungs
What occurs when asthma is triggered?
hypertrophy of muscle increase in inflammatory cells sputum in airway smooth muscle contraction airways may become scarred effects can be temporary or permanent
What happens during an asthma attack?
airway narrowing caused by:
- contraction of smooth muscle
- swelling of epithelium
- increase mucus production
What are the 4 asthma symptoms?
coughing usually dry
wheezing - whistley noise on expiration
chest tightness
SOB
What are some asthma triggers?
allergens e.g. animal dander, pollen, foods
irritants e.g. smoke, aerosols, particulate matter
other e.g. viruses, changes in weather, exercise, endocrine factors
Give four examples of substances that can cause occupational asthma
isocyanates - paints, varnishes, plastics
colophony - soldering
proteolytic enzymes - cleaners
flour dust - bakers
What are the 4 components of an asthma management plan?
medication
identification of triggers
peak flow monitoring
emergency plan
What are the 2 forms of inhaled asthma therapy?
bronchodilators, B2 agonist, targets smooth muscle contraction
steroids, targets inflammation
When are oral steroids likely to be used?
rarely needed in maintenance therapy
play a role in acute exacerbations
What are the 5 steps of asthma medication?
1 = SABA 2 = inhaled steroid 3 = LABA 4 = increase steroid, try leukotriene antagonist or theophylline 5 = oral steroids
What is COPD?
chronic obstructive pulmonary disease
characterised by obstruction that is not fully reversible
What is the pathogenesis of COPD?
What are the components of COPD?
smoking
stimulate neutrophilic inflammation
release oxidants and proteases
parenchymal damage and mucus hypersecretion
- airway inflammation, bronchospasm, structural changes, mucociliary dysfunction, systemic components
What are the severity gradings for COPD?
FEV1/FVC 80%
moderate 50-80%
severe 30-50%
How do you differentiate between COPD and asthma:
- smoking status
- symptoms under age 35
- chronic productive cough
- breathlessness
- night time waking with breathlessness or wheeze
- signification diurnal variability of symptoms
COPD / ASTHMA
- nearly all / possibly
- rare / often
- common / uncommon
- persistent and progressive / variable
- uncommon / common
- uncommon / common
How is COPD managed in terms of drugs?
- SABA
- LABA
- ultimately use steroids
What is the only thing you need to diagnose COPD?
spirometry
FEV1/FVC ratio
What are the three features of an excacerbation in COPD?
What is the treatment?
increased breathlessness
green sputum
increased sputum volume
anitbiotics, steroids
What is pulmonary fibrosis?
scarring of the lung parenchyma
usually happens after inflammation
What are the clinical features of pulmonary fibrosis and the results of investigations>
dry cough and dyspnoea
fine end inspiratory reps at base of lungs
of the cause
cryptogenic
restrictive pattern on spirometry
CXR = reticular shadowing, honeycombing
High resolution CT = sub plural reticular shadowing
How is pulmonary fibrosis managed?
depends on cause, histology, severity
immunosupression
transplantation
monitor using PFT’s
What is the checklist for good asthma control?
no daytime symptoms no night time waking no need for reliever medication no exacerbations no limitation of physical activity normal lung function
