asthma Flashcards
what is asthama
Asthma is a chronic inflammatory airway disease leading to variable airway obstruction. The smooth muscle in the airways is hypersensitive and responds to stimuli by constricting and causing airflow obstruction. This bronchoconstriction is reversible with bronchodilators, such as inhaled salbutamol.
typical symptoms of asthma?
Shortness of breath (dysponea)
Chest tightness
Dry cough
Wheeze
occasional sputum
symptom variability- often worse at beginning or end of the day, may have annual variation etc
risk factors for asthma
Hereditary
maternal smoking during pregnancy reduces lung development which can lead to asthma.
occupation
obesity, diet and hygiene may also be POSSIBLE risk factors
explain the hereditary impact for asthma
Atopy is the bodies predisposition to develop antibody called IgE in response to exposure to environmental allergens and its an inheritable trait.
explains why people are like to have a combination of asthma, hay-fever and eczema
taking a full history is important in diagnosing asthma- what are the key components?
Symptoms
evidence of variable symptoms
triggers (that cause variable symptoms)
PMH- history of asthma of other lung conditions or other atopic conditions
Drugs- current inhalers and medical compliance
family history- asthma and other atopic disease
social history- occupation, smoker, pets etc.
what will be seen on clinical examination of asthma?
breathless on exertion
wheeze
hyper inflated chest
intermediate probability of asthma, what more info is needed to make a diagnosis
evidence of:
airflow obstruction- FEV1/FVC<70% indicates asthma
or
variability/ reversibility of obstruction
-give patient bronchodilators and and see if that effects fev1/fvc
- can also give coticosteroids for two weeks which are antinflammtory drugs and repaet a peak flow chart. helps seperate asthma from copd
specialist investigations of asthma when spirometry is normal ?
chest x-ray
skin prick testing
total and specific IgE
full blood count, looking at eosionphillia
how is asthma assessed objectively?
ability to speak
heart rate
resp rate
PEF- peak flow
oxygen saturation/aterial blood gasses
how is the severity of asthma graded?
moderate
severe
life threatening
near fatal
moderate
presents with increasing symptoms
able to speak complete sentences
severe asthama
inability to complete sentences in one breath
HR over 110
RR over 25
PEF 33-50%
Sao2 over 92%
pao2 over 8kPa
life threatening
meets any one of the following:
Grunting
Impaired consciousness, confusion, exhaustion
Bradycardia/ arrhythmia/ hypotension
PEF < 33% predicted or best
Cyanosis
Silent chest
Poor respiratory effort
SaO2 < 92% (definitely needs blood gas!)
PaO2 < 8kPa
PaCO2 normal (4.6 - 6.0kPa)
near fatal
raised paco2
need for mechanical ventilation
how do asthamtic airways differ to normal one?
an asthmatic airway at ‘rest’ has an inflamed, thickened wall. during an attack the smooth muscle surrounding airways tighten, trapping air in alveoli.
