Asthma Flashcards
the most common chronic respiratory disorder
asthma
asthma
chronic inflammatory disorder of the airways
secondary to type 1 hypersensitivity
variable and recurring symptoms manifest as reversible bronchospasm resulting in airway obstruction.
asthma risk factors
atopy
antenatal factors:
- maternal smoking
- maternal viral infection (RSV)
birth factors:
- low birth weight
- not being breastfed
environmental:
- smoke
- allergens (house dust mite)
- air pollution
‘hygiene hypothesis’:
number of patients with asthma are sensitive to?
aspirin
patients who are most sensitive to asthma often suffer from?
nasal polyps
asthma signs & symptoms
symptoms: cough (nocturnal), dyspnoea, wheeze
signs:
auscultation: expiratory wheeze
PEFR (peak expiratory flow rate): reduced
typical spirometry results in asthma?
FEV1 - significantly reduced
FVC - normal
FEV1% (FEV1/FVC) < 70%
asthma adults investigations
exclude occupational asthma
spirometry + a bronchodilator reversibility (BDR) test
FeNO test
asthma children (5-16 y/o) diagnosis
spirometry + a bronchodilator reversibility (BDR) test
FeNO test
asthma children (<5 y/o) diagnosis
clinical judgement
FeNo positive test
in adults level of >= 40 parts per billion (ppb)
in children a level of >= 35 parts per billion (ppb
what does a reversbility test measure?
FEV1
positive reversibility test
FEV1 improvement of 12% or more
how does FeNO work?
nitric oxide is produced by 3 types of nitric oxide synthases (NOS).
one of the types is inducible (iNOS) and levels tend to rise in inflammatory cells, particularly eosinophils
levels of NO therefore typically correlate with levels of inflammation.
asthma management in adults
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS + LABA
continue LTRA depending on patient’s response to LTRA
maintenance and reliever therapy (MART)
a form of combined ICS and LABA treatment
a single inhaler (ICS + LABA) used for daily maintenance therapy and the relief of symptoms as required
Describe low, moderate and high doses of ICS
<= 400 micrograms budesonide or equivalent = low dose
400 micrograms - 800 micrograms budesonide or equivalent = moderate dose
> 800 micrograms budesonide or equivalent= high dose
paeds 200/ 200-400/ >400
asthma management in <5
- SABA
- SABA + an 8-week trial of MODERATE-dose inhaled corticosteroid (ICS)
- SABA + low-dose ICS + LTRA
- Stop the LTRA and refer to an paediatric asthma specialist
when should we consider stepping down asthma treatment?
every 3 months or so
take into account duration of treatment, side-effects and patient preference
when reducing the dose of inhaled steroids the BTS advise us to do this by what increments?
25-50%
acute asthma features
worsening dyspnoea, wheeze and cough that is not responding to salbutamol
maybe triggered by a respiratory tract infection
moderate acute asthma
PEFR 50-75% best or predicted
Speech normal
Pulse < 110 bpm
RR < 25 / min
PSPR
severe acute asthma
PEFR 33 - 50% best or predicted
speech: can’t complete sentences
Pulse > 110 bpm
RR > 25/min
PSPR
life-threatening acute asthma
P - PEFR < 33% best or predicted
S - Exhaustion, confusion or coma
P - Bradycardia, dysrhythmia or hypotension
R - Silent chest, cyanosis or feeble respiratory effort
Oxygen sats < 92%
PSPR
normal pCO2 in an acute asthma attack is a good sign
FALSE
indicates exhaustion and should, therefore, be classified as life-threatening.
near-fatal asthma
fourth category
characterised by a raised pC02 and/or requiring mechanical ventilation with raised inflation pressures
important step in further assessment of acute asthma?
arterial blood gases for patients with oxygen sats < 92%
CXR is routinely performed in acute asthma attacks
not routinely recommended
unless:
life-threatening asthma
suspected pneumothorax
failure to respond to treatment
when should patients be admitted to hopsital?
life-threatening asthma
severe acute asthma & fail to respond to initial treatment
previous near-fatal asthma attack
pregnancy
attack despite using oral corticosteroid
presentation at night
acute asthma attack management
oxygen: 15L of supplemental via a non-rebreathe mask
SABA
hydrocortisone or prednisolone (40-50mg) for at least five days
ipratropium bromide
IV aminophylline
IV magnesium sulphate
ITU/HDU
acute asthma attack discharge criteria
stable on their discharge medication (no nebulisers or oxygen) for 12–24 hours
inhaler technique checked and recorded
PEF >75% of best or predicted
asthma in children: how do you assess acute attacks?
severe attack or life-threatening attack
severe asthma attack in kids
SpO2 < 92%
PEF 33-50% best or predicted
Too breathless to talk or feed
Heart rate
>125 (>5 years)
>140 (1-5 years)
Respiratory rate
>30 breaths/min (>5 years)
>40 (1-5 years)
Use of accessory neck muscles
life threatening asthma attack in kids
SpO2 <92%
PEF <33% best or predicted
Silent chest
Poor respiratory effort
Agitation
Altered consciousness
Cyanosis
chemicals associated with occupational asthma
isocyanates - most common cause
spray painting and foam moulding using adhesives
platinum salts
soldering flux resin
glutaraldehyde
flour
epoxy resins
proteolytic enzymes
