Defination
Asthma is characterized by chronic airway inflammation and increased airway hyper-responsiveness leading to symptoms of wheeze, cough, chest tightness and dyspnoea.
It is characterised functionally by the presence of airflow
obstruction which is variable over short periods of time, or is reversible with
treatment.
Classification of asthma
- Aetiological
A. Intrinsic asthma : non-allergic, can begin at any age ,
esp. at late childhood. No role of allergen. Occurs due to stimuli such as
infection, cold air , exercise and
emotional upset.
B. Extrinsic asthma :
Allergic.
Starts in childhood.
Family history of allergic disease.
Precipitated by allergen.
Precipitating factors
Ø In
sensitive people, asthma symptoms can be triggered by breathing in
allergy-causing substances (called allergens or triggers).
Ø Common
asthma triggers include:
- Animals (pet hair or dander)
- Dust
- Changes in weather (most often cold weather)
- Chemicals in the air or in food
- Exercise
- Mold
- Pollen
- Respiratory infections, such as the common cold
- Strong emotions (stress)
- Tobacco smoke
- Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) provoke asthma in some patients.
Clinical features
Ø Most
people with asthma have attacks separated by symptom-free periods
A. Symptoms include:
- cough with mucopurulent sputum
- Shortness of breath that gets worse with exercise or activity
- Chest tightness
- Wheezing, which:
l Comes
in episodes with symptom-free periods in between
l May
be worse at night or in early morning
l May
go away on its own
l Gets
better when using drugs that open the airways (bronchodilators)
l Gets
worse with exercise
l Usually
begins suddenly
B. Signs
- Patient dyspnoeic , slightly bends forwards
- Tachycardia , tachypnoea
- Sweating
- Cyanosis
Investigations
- CBC : leucocytosis, eosinophilia
- Sputum for GM stain, C/S : Inflammatory cells, Curschmann's spirals and Charcot-Leyden crystals in sputum
- Increased serum level of IgE
- 4. CXR PA view : hyperinflation of lungs , low standing flat diaphragm
- Chest X-ray reveals
- Ø hyperlucency of lung fields
- Ø low standing and limited mobility of diaphragm
- Ø expanded intercostal spaces
- Ø horizontal rib position.
5. Pulmonary function tests: for diagnosis
- FEV1 > 15% increase after use of bronchodilator
- > 20% diurnal variation
- FEV 1> 15% decrease after exercise
Management
General management
- Patient education about the disease and its symptoms.
- Avoidance of aggravating factors: Removing animals from the home, replacing carpets with mite impermeable carpets, reduce the fungal exposure etc.
- Stop smoking.
2.
Pharmacolgical
management
A step wise approach
Step 1. occasional use of inhaled
short acting beta-2 agonist bronchodilators--- salbutamol or terbutaline
Step 2: inhaled beta 2 agonist + low dose
inhaled corticosteroids --- beclomethasone dipropionate, budesonide,
fluticasone
Step 3 : moderate dose inhaled
corticosteroids+ long acting beta-2 agonist (salmeterol or formeterol) or
leukotriene receptor antagonist
(montelukast)
Step down thepapy
Ø Once
asthma is controlled the dose of the drugs is decreased.
Complications of asthma
- Exhausted ,dehydrated
- Cor –pulmonale
- Respiratory failure
- Pneumothorax
