Asthma Flashcards
What is the lifethreatening peak flow for asthma?
PEFR <33% baseline
Criteria for asthma patinet -> hospital
-Can’t finish sentence
Blue inhaler more than hourly
RR over 20
When is asthma worse
First thing morning and at night - diurnal variation in PEFR
What is asthma?
Chronic inflammatory condition of the AWs characterised by hyperresponsiveness and constriction in response to variety of stimuli
Intermittent symptoms but inflammation can lead to irreversible AW obstruction
Pathophysiology of asthma
Excessive Th2 mediated IgE immune response to exposure of environmental pathogen.
IgE bonds to bronchial mast cells -> degranulation + release of pro inflammatory mediators
Phases of inflamamtion
Acute phase - bronchosconstirction and AW oedema
Delayed phase - bronchial hyperresponsiveness
How does the delayed phase of asthma cause bronchial hyperresponsiveness?
Delayed phase = Pro inflammatory mediators eg IL5 recruit eosinophils, basophils and Th2 lymphocutes -> inflammation, sensitisation of sensory nerve endings, -> bronchial hyperresponsiveness
What is the acute phase of asthma?
bronchosconstriction + AW oedema - within minutes exposure, resolves within hours
Risk factors for asthma
Personal history of atopy - eczema, hayfever
FH asthma or atopy
Inner city environment, socioeconomic deprivation
Obesity
Prematurity and low birth weight
Viral infections in early childhood
Smoking
Maternal smoking
Early exposure to broad spectrum antibiotics
Asthma triggers
Resp inections
Cold air
Exercise
Pollution
Allergens eg pollen, dust mites, animals
Time of day
Work related
Drugs eg beta blockers, NSAIDs
Emotional factors eg stress, laughter
GORD
Symptoms of asthma
Intermittent SOB
Wheeze - polyphponic
Cough often nocturnal, with or without sputum
Asthma signs
Decreased chest expansion
Bilateral polyphonic wheeze
Tachypnoea
Tachycardia
Reduced air entry
Hyperinflated chest
Complications of asthma
Pneumonia
Pneumothorax
Pneumomediastinum
Respiratory failure and arrest
Pulmonary collapse
Investigations for acute asthma
Bloods
ABG - if sPO2 <92%
CXR - rule out pneumonia/pneumothorax, normal or hyperinflation and flattened diaphram
Peak flow - % of patients previous best value
ECG - often sinus tachycardia
Investigations for chronic asthma
Spirometry
Peak flow
FeNO
Bloods in acute asthma and what for
FBC - raised WCC + typically eosinophilia
U+Es - salbutamol -> hypokalemia
CRP - rule out infection
What spirometry value is considered obstructive?
FEV1/FVC ratio under 70%
What is the other option except spirometry for obstruction measuring?
Bronchodilator reversibility reversibility tes t indicated by improbement 12% FEV1 or more and increased involume 200ml
What is PEFR useful for in asthma?
Monitoring patients with established astham
Basic
Diurnal variation
What is FeNO?
Gold standard for diagnosing asthma, fractional exhaled nitric oxide
Measures level of NO in exhaled breath _ provides indication of eosinophilic inflammation in lungs - adults >40 = positive
Grading of asthma
Moderate
Severe
Life threatening
Near fatal
Moderate asthma parameters?
PEFR 50-75% predicted or best
Speech normal
RR <25/min
Pulse <110BPM
What is the SpO2, PaO2 and PaCO2 in life threatening asthma?
SpO2 <92%
PaO2 <8kPa
‘Normal’ PaCO2
Parameters for severe asthma
PEFR 33-50% best or predicted
Can’t complete sentences
RR > 25/min
Pulse >110BPM
Life threatening asthma symptoms
Altered consciousness level
Exhaustion
Arrhythmia
Hypotension
Cyanosis
Silent chest
Poor respiratory effort
Life threatening asthma symptoms
Altered consciousness level
Exhaustion
Arrhythmia
Hypotension
Cyanosis
Silent chest
Poor respiratory effort
When is life threatening asthma nearly fatal?
Raised PaCO2 and or requiring mechanical ventilation with raised inflation pressures
Management of acute asthma
Sit patient up and high flow oxygen 15 L
Nebulised beta 2 agonist - salbuatmol 5mg and nebulised antimuscarinic - ipatropium bromude 0.5mg
Corticosteroid: prednisolone (40-50mg) or IV hydrocortisone
Consider IV magnesium sulphate (1.2-2.0g IV over 20 min). If little response to above considerIV aminophylline
ITU referral
What is slabutamol?
Beta 2 agonist
What is an antimuscarinic used in treatment of acute asthma?
ipatropium bromide - 0.5mg
When refer acute asthma to ITU?
Fail to respond to theray eg
Deteriorating PEF, persisting or worsening hypoxia, hypercapnia, resp acidosis, exhaustion, feeble respiration, drowsiness, confusion, altered consciousness state, respiratory arrest
Management for acute asthma pneumonic
O SHIT ME
Oxygen
Salbutamol
Hydrocortisone
Ipatropium
Theophylline
Magnesium sulphate
Escalation
How does ipatropium work?
Antimuscarinic - prevent smooth muscle contraction in larger airways
Management chronic asthma phase 1
Short acting beta agonist SABA eg Salbutamol
If nto controlled on this SABA + low dose inhaled corticosteroid eg beclomethasone or budesonide
Second stage chronic asthma management
Add Leukotriene receptor antagonist (LTRA) eg montelukast 10mg OD to existing SABA and low dose ICS
What drug do you perscribe if a LTRA doesnt work in chronic asthma?
add a LABA (long acting beta agonist) eg formoterol, potnetially continuing LTRA if still responded a bit to it
What are the options for unresponding chronic asthma?
MART - maintenance and reliever therapy incl low dose ICS eg symbicort (budenoside with formoterol)
Long acting antimuscarinic receptor antagonist eg tiotropium , theophylline
What class of drug is theophylline, tiotropium
Long acting antimuscarinic receptor antagonist
Signs that asthma is unmanaged
Symtpoms are coming back - wheeze, tight chest, SOB, cough
Nocturnal, waking up
Symptoms interfering with ADL
Using reliever inhaler 3x or more a week
How many hours in between needing an inhaler counts as an asthma attack?
if more than every 4 hours - having an asthma attack, need to take emergency action
When is someone having an asthma attack?
Need a reliever inhaler more than every 4 hours
Difficult to walk or talk
Difficult to breathe
Wheezing a lot or have v tight chest or coughing a lot
What to do in an asthma attack
Sit up straight and try and keep calm
Take one puff of your reliever inhaler - blie every 30-60s, max of 10 puffs
If feel worse or dont feel better after 10 puffs call 999
Repeat step 2 after 15 minutes while waiting for an ambulance
See GP within 48 hours
What to monitor in asthma review?
- Peak flow
- Education
- Symptom recognition
- quality life indicators eg
- symptoms during day
- difficulty sleeping
- usuial activities
What to ask specifically in an asthma history?
- Best peak flow
- Home nebulisers
- Recent exacerbations and antibiotics
- ICU admissions
