Asthma Flashcards
What causes narrowin of airways?
Inflammation caused by over reactive immune system
Narrowing of airways due to smooth muscle contraction.
Name one distinguishing feature of Asthma
It is reversible obstruction of airways.
How is FEV1/FVC affected?
Restriction on airflow= harder for air to flow in and out= lower ratio <70% (during an attack)
What methods can we use to diagnose asthma?
Peak flow monitoring
Spirometry- FEV1/FVC PFT
Reversibility - bronchodilators and steroids.
Name 6 risk factors relating to asthma
- Genetic atopic tendency (IgE)
- Occupation
- Diet- low in polyunsaturated FA
- Environmental- less exposure= more asthma.
- Indoor Pollution- aerosols, chemicals
- Obesity- high BMI=high risk.
Name some other causes of wheeze;
- Cystic Fibrosis
- COPD
- Lung cancer (obstruction)
- Pneumonia (obstruction)
- Bronchiectasis
- Bronchiolitis
Name the symptoms of Asthma
- Wheeze
- Intermittent dry cough
- Breathlessness on exertion
- Relieved by inhalers.
- Worse at night/ in the morning
- Chest pain (tight band around chest)
What is a bronchial provocation test?
A test done in a controlled environment which artificially causes bronchial constriction by introducing histamine or methacholine.
Why use pulmonary function tests?
To exclude COPD and emphysema
How long would you wait after giving Salbutamol before measuring the response and what are the doses?
- 15 mins
- 400 micro grams/ 2.5 nebuliser
How would you measure the response to oral steroids?
Give prednisolone 0.6mg/kg for 14/7
- Give peak flow chart to monitor
- Show if breathlessness is reversible.
Other investigations?
CXR
Skin Prick
IgE
FBC (look for elevated eosinophils in infection)
Name the levels of severity and one defining feature.
Moderate- no impact on speech
Severe- struggles to complete sentences
Life threatening- no speech, o2 <92%, cyanosis
Near Fatal- high Pa Co2
