asthma lms Flashcards
airway hyperresponsiveness
exxaggerated response to noxious stimuli
present in all asthmatics
leads to airway inflammation which leads to airflow obstruction
airway obstruction leads. to
smooth muscle hypertrophy
inflammatory cell infiltration
oedema
goblet cell / mucous gland hyperplasia
mucus hypersecretion
protein deposition eg. collagen
risk factors for asthma
atopy/allergy - high igG
genetics
pollution
smoking
obesity
triggers for asthma
viral upper and lower respiratory tract infections
exposure to pollutants
exposure to cold air
smoking
exercise
exposure to chemicals/irritants
cats and allergens
symptoms
breathlessness
wheeze
tight chest
cough
sputum
variable in severity and time
always worst at night
signs
when the patient is well there are no signs
when active there may be wheeze
resp rate increased and tachycardia
difficulty speaking if severe asthma attack
diagnosis
no single diagnostic test
good histroy
peak flow twice a day for a period of two weeks can reveal variable airflow obstruction
FEV1: better tesst but harder to perform
spiromtry and peak flow in a well asthmatic will be normal
good reponse to inhaled bronchodilators corticosteoids
bronchial provocation testing
if the diagnosis is really in doubt
to decide whether there is airway hyperresponsiveness - absense will rule out asthma
methacholine or histamine challenge
what is bronchial provocation testing
methacholine or histamine challenge
- increasing concentrations via nebuliser
FEV1 measured. at 1,3,5, and 10 minutes
continue until FEV1 drops by 20% or more
if FEV1 drops by 20% before a predetermined point, airway hyperresponsiveness is considered to be present
step 1 therapy
- aas required SABA
or - as required ICS + formoterol
step 2 therapy should be initiated when
symptoms or need for reliever therapy twice a month or more
step 2 therapy
regular daily low dose ICS plus as needed SABA
OR
as required low dose ICS + formoterol
when to step up to step 3 therapy
troublesome asthma most days or waking due to asthma, or poor control despite step 2 therapy
step 3 therapy
regular daily low dose ICS plus LABA and as required SABA
OR
regular daily low dose ICS plus formoterol plus as required low dose ICS plus formoterol
step 4 therapy
regular daily low dose ICS plus LABA and as required SABA
OR
regular daily medium dose ICS plus formoterol plus as required low dose ICS plus formoterol
consider referral to specialist and adding a LAMA while awaiting referral
step 5 therapy
refer to specialist for other therapies
consider
regular daily high dose ICS plus formoterol plus as required low dose ICS plus formoterol
consider adding a LAMA
SABA relievers
salbutamol
terbutaline
preventers
seretide
symbicort
flutiform
all contain ICS and LABA
non pharmacological issues
inhaler technique
compliance
triggers - pets, smoking
allergy testing
occupation
difficult asthma
harder to treat in obese patients
LTRA - montelukast, oral steroids
always involve a specialisst
management of acute asthma attack
oxygen
bronchodilators
(8-12 puffs salbutamol or via oxygen driven nebuliser 2.5-5mg)
oral steroids: prednisolone 30-40mg IV steroids have no real advantage
other agents that can be used. for acute asthma attack
Atrovent (MDI or nubulised) - can add if response is poor
Aminophylline - can give IV if severe, but potential for toxicity
magnesium sulphate
severity assessment of asthma attack
resp rate
pulse rate
PEFR or FEV1
speech
wheeze
pulse oximetry on air at presentation - not reliable if on oxygen
pCO2 and severity
mild/moderate asthma - CO2 will be low
severe asthma - CO2 will rise and be either normal or high
beware the asthmatic with a normal pCO2
