| Written by Dr.Md.Redwanul Huq (Masum) |
| Sunday, 15 January 2012 16:00 |
Definition:
Bronchial asthma is defined as a chronic inflammatory airway disease characterized by hyper responsiveness to lots of allergens leading to bronchospasm which is manifested by wheeze, cough, chest tightness, with or without breathlessness which is reversible in nature.
Classification of asthma (Types of asthma):
Bronchial asthma can be classified in following two ways-
a) Clinical classification
b) Etiological classification.
a) Clinical classification of asthma:
Clinically Bronchial asthma is classified as-
- Episodic or Paroxysmal asthma
- Chronic asthma
- Acute Severe asthma
There is a special type named cough-variant asthma where nonproductive cough is the dominant symptom.
b) Etiological classification of asthma (Causes of asthma):
Etiologically Bronchial asthma is classified as-
- Atopic asthma- genetically determined
- Non-atopic asthma ( Intrinsic asthma)- IgE mediated
Risk factors of asthma:
a) Endogenous factors:
1.Atopy (Increased level of IgE antibody in blood)
2.Genetic factor- Family history positive for different atopic or allergic diseases like bronchial asthma, allergic rhinitis, eczema etc
3.Hypersensitivity of the airway
4.Gender- more in male
b) Environmental factors:
1.Allergens (e.g. house dust mites, smoke, fumes, pollens, cosmetics, dirty clothes or carpets, prawn, brinjal etc)
2.Air pollutants (e.g. ozone, sulfur dioxide, diesel particulates etc)
3.Occupational exposure to sensitizing agents(e.g. trimellitic anhydride,toluene Diisocyanate etc)
4.Diet low in antioxidants and omega-3 PUFA (Polyunsaturated fatty acids) or high in sodium and omega-6 PUFA
5.Obesity.
Aggrevating factors of asthma:
- Physical exercise
- Allergens
- Viral infections of upper respiratory tract
- Stress
- Emotion
- Smoking
- Drugs like Beta blockers, Aspirin etc
- Exposure to cold air or water.
Episodic or Paroxysmal asthma
History:
1.Family history of Bronchial asthma or other atopic or allergic diseases like allergic rhinitis, eczema etc
2. Symptoms of Bronchial asthma from childhood.
Symptoms of paroxysmal asthma:
Occasional development of one or more of the following symptoms(which recover spontaneously or with bronchodilators)-
- Wheeze
- Cough
- Chest tightness
- Breathlessness
Signs:
1.Wheeze
2. Signs of respiratory distress like-
- Increased respiratory rate
- Pursing lip
- Cyanosis
- Tracheal tug
- Suprasternal and intercostal recession
- Prominent accessory muscles of respiration
3.Breath sound- Vesicular with prolonged expiration
4.Rhonchi- present bilaterally
5.Creps- may be present.
Investigations:
Described later.
Treatment of paroxysmal asthma:
1. Short-acting beta 2-adrenoreceptor agonist bronchodilators (e.g. salbutamol, terbutaline) is the first choice which is used only during episode. These drugs are available in inhaler and oral form between which the former is better.
Inhaler: 2 Puffs-when required.
Oral: 2mg or 4mg tab bid or tid.
2. If symptoms are not relieved even after use of the above drug steroid inhaler, e.g. Beclomithasone should be used- 2 puffs-bid.
Chronic asthma:
History:
1.Family history of Bronchial asthma or other atopic or allergic diseases like allergic rhinitis, eczema etc
2. Symptoms of Bronchial asthma from childhood.
Symptoms of chronic asthma:
Recurrent or persistent episodes of the following symptoms (characteristically show a diurnal pattern and PEF becomes worse in the early morning) –
- Wheeze
- Cough
- Chest tightness
- Breathlessness
- Tiredness with activities that one normally could complete easily
- Restless sleep or waking up tired
- Worsening allergy symptoms like persistent runny nose, dark circles under eyes or itching under the chin
Signs:
In asymptomatic patients-There may be no sign.
In symptomatic patients-
1.Wheeze
2. Signs of respiratory distress like-
- Increased respiratory rate
- Pursing lip
- Cyanosis
- Tracheal tug
- Suprasternal and intercostal recession
- Prominent accessory muscles of respiration
3.Breath sound- Vesicular with prolonged expiration
4.Rhonchi- present bilaterally
5.Creps- may be present.
Investigations:
Described later.
Treatment of chronic asthma:
Stepwise treatment of chronic bronchial asthma-
| Steps | Asthma status/ symptoms | Treatment |
| STEP 1 | Mild intermittent asthma (Symptoms appear less than once in a week for 3 months and less than two nocturnal attacks per month) | For more than 5 years to adults: Short-acting beta2 -agonist bronchodilator (e.g. salbutamol, terbutaline) inhaler- 200 mcg (2 puffs) at a time when required, up to 4-6 times per day. Additional 2 puffs before exercise or heavy work.
For 5 years or less: Short-acting beta2 -agonist bronchodilator inhaler- 100-200 mcg (1-2 puffs) at a time when required, up to 4-6 times per day. Additional 1-2 puffs before exercise or sports. |
| STEP 2 | Mild persistent asthma ( When patient has one or more of the followings-1.Symptoms appear three times or more in a week2.Has developed an exacerbation of bronchial asthma in last 2 years3.Wake up in one night for asthmatic attack per week 4.Used beta 2 -agonist inhalers three times or more in a week) | STEP 1 +
For more than 5 years to adults: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) Low dose-For 5-12 years: 200-400 mcg per day preferably in two divided doses.For more than 12 years to adults: 400-800 mcg per day preferably in two divided doses. For 5 years or less: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) Low dose- 100-250 mcg per day preferably in two divided doses. [Fluticasone and Mometasone exert similar efficacy at half the dosage of Beclomethasone or Budesonide] |
| STEP 3 | Moderate persistent asthma(Symptoms are not well controlled even after use of ICS low dose) | STEP 2 +
LABA(Long-acting beta2 -agonists, e.g. Salmeterol,Bambuterol or Formoterol) bronchodilator inhaler Or, Leukotriene antagonists (e.g. Montelukast 5-10 mg daily) Or, SR(Sustained release) Theophylline Or, Ipratropium bromide inhaler ALTERNATIVE TREATMENT: STEP 1+ For more than 5 years to adults: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) High dose-For 5-12 years: up to 800 mcg per day preferably in two divided doses. For more than 12 years to adults: up to 2000 mcg per day preferably in two divided doses. For 5 years or less: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) Medium dose- 250-500 mcg per day preferably in two divided doses. [Fluticasone and Mometasone exert similar efficacy at half the dosage of Beclomethasone or Budesonide] |
| STEP 4 | Severe persistent asthma(Symptoms are not well controlled even after getting treatment of STEP 3) | STEP 1 +
For more than 5 years to adults: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) High dose-For 5-12 years: up to 800 mcg per day preferably in two divided doses.For more than 12 years to adults: up to 2000 mcg per day preferably in two divided doses. + LABA (Long-acting beta2 -agonists, e.g. Salmeterol,Bambuterol or Formoterol) bronchodilator inhaler &/Or, Leukotriene antagonists (e.g. Montelukast 5-10 mg daily) &/Or, SR(Sustained release) Theophylline &/Or, Ipratropium bromide inhaler For 5 years or less: ICS (Inhaled corticosteroids, e.g. Beclomethasone or Budesonide) High dose- 500-800 mcg per day preferably in two divided doses. OR, ICS High dose +LABA(Long-acting beta2 -agonists, e.g. Salmeterol,Bambuterol or Formoterol) bronchodilator inhaler Or, Leukotriene antagonists (e.g. Montelukast 5 mg daily) Or, SR(Sustained release) Theophylline Or, Ipratropium bromide inhaler. [Fluticasone and Mometasone exert similar efficacy at half the dosage of Beclomethasone or Budesonide] |
| STEP 5 | Very severe persistent asthma (Symptoms are poorly controlled with all above measures) | STEP 4 +
Oral corticosteroids (usually prednisolone or prednisone) 30 – 45 mg od in the morning for 5-10 days, then the lowest dose required to control symptoms(usually 7.5-10 mg od in the morning) should be continued if necessary. |
Step Down Therapy: When the symptoms of asthma are under control, the therapy should be decreased slowly to the lowest dose at which effective control of symptoms of asthma is maintained.
Acute Severe asthma:
History:
1.Family history of Bronchial asthma or other atopic or allergic diseases like allergic rhinitis, eczema etc
2. Symptoms of Bronchial asthma from childhood
Symptoms of acute severe asthma:
1.Increased wheezing, chest tightness and breathlessness even after taking usual treatment
2.Breathlessness may become so severe that patient cannot complete sentences in a single breath.
Signs:
General examination-
1.Patient looks exhausted, may be in confusion or coma
2.Signs of respiratory distress
3.Decubitus-Upright, fixing the shoulder girdle
4.Sweating may be present
5.Central cyanosis may be present in asthma attack
6.Pulse-Tachycardia (Pulse rate: 110 or more/min),In very severe cases there may be bradycardia,
Pulsus paradoxus may be present
7.Hypotension
Examination of Respiratory system-
1.Inspection–
Increased respiratory rate- 25 or more/min
There may be feeble respiratory effort or even silent chest in very severe cases
2.Palpation-
Movement of the chest wall- diminished, symmetrically (may be absent in very severe cases)
Chest wall expansion- reduced
Vocal fremitus-may be diminished symmetrically or absent(in silent chest)
3.Percussion-
May be hyper resonant on both sides
4.Auscultation–
Breath sound- vesicular with prolonged expiration (No breath sound in silent chest)
Rhonchi (High pitched) – both inspiratory and expiratory (No rhonchi in silent chest)
Investigations:
Described later.
Treatment of acute severe asthma attack-
Immediate treatment:
1.Position: Propped up position of the patient
2.Oxygen: High concentrations of oxygen (4-6 liters/min) should be given by face mask to maintain the oxygen saturation more than 92% in adults
3.Nebulization: Respiratory solution of short-acting beta2-agonist bronchodilator (e.g. salbutamol, terbutaline etc) with(if needed) or without Ipratropium bromide are given stat by nebulizer to reduce symptoms of asthma
4. Intravenous (IV) beta2- agonist: In patients with impending respiratory failure- IV beta 2-agonist can be given
5.Parenteral or Oral Steroids: Inj. Hydrocortisone 200 mg IV or Oral Prednisolone 30-60 mg stat
6. Intravenous fluids: Dehydrated patients should be given Intravenous fluids
Subsequent treatment:
If patient improves:
1. High concentrations of oxygen should be continued until cyanosis persists or blood gas analysis shows normal levels
2.Nebulization should be reduced- 4 hourly, 6 hourly, 8 hourly, 12 hourly and then inhalers should be started
3. Inj. Hydrocortisone 200 mg IV should be reduced- 6 hourly, 8 hourly, 12 hourly and then oral prednisolone should be started at a dose of 30 – 45 mg od in the morning for 5 – 10 days, then the lowest dose required to control symptoms (usually 7.5-10 mg od in the morning) should be continued if necessary.
If patient does not improve:
1. High concentrations of oxygen should be continued
2. Nebulization should be repeated after 30 minutes and continued hourly until patient improves
3. Magnesium sulfate may be given IV or by inhaler in patients with PEF < 30% predicted
4. Slow infusion of Aminophylline can be administered as following-
Inj. Aminophylline 125 mg/5ml amp- 2 amp in 500 ml Normal Saline IV @ 10-15 drops/min
5.Antibiotic(s) should be used when there are signs of Pneumonia
6.Assisted Ventilation is needed in following conditions-
- Exhaustion,
- Drowsiness,
- Confusion,
- Coma,
- Respiratory arrest
- PaCO2 is more than 6 kPa (45 mmHg) and increasing
- PaO2 is less than 8 kPa (60 mmHg) and decreasing
- pH is low and decreasing i.e. H+ concentration is high and increasing
Treatment monitoring:
1. PEF of the patient should be monitored every 15-30 minutes and then 4-6 hourly
2. Oxygen saturation should be monitored by pulse oximetry and maintained more than 92% in adults
3.Arterial blood gas analysis should be repeated if there are indications of assisted ventilation.
Investigations for bronchial asthma:
Bronchial asthma is diagnosed apparently from its history, symptoms & signs and
confirmed by following investigations:
| Investigations | Expected findings | ||
| Episodic or Paroxysmal asthma | Chronic asthma | Acute Severe asthma | |
| 1.Lung function tests | |||
| a) PEFR(Peak Expiratory Flow Rate) [Diagnostic] | Diurnal variation in PEF of more than 20% with morning deeping (lowest value of PEF is in the morning) | Diurnal variation in PEF of more than 20% with morning deeping (lowest value of PEF is in the morning) | Diurnal variation in PEF of more than 20% with morning deeping (lowest value of PEF is in the morning) |
| b) Spirometry | Reduced FEV 1 and FEV 1 /FVC ratio | Reduced FEV 1 and FEV 1 /FVC ratio | Reduced FEV 1 and FEV 1 /FVC ratio |
| Demonstration of reversibility: FEV 1 is increased by 15%(200 ml)- 15 min after an inhaled short-acting beta 2 -agonist [Diagnostic] | Demonstration of reversibility: FEV 1 is increased by 15%(200 ml)- 15 min after an inhaled short-acting beta 2 -agonist [Diagnostic] | Demonstration of reversibility: FEV 1 is increased by 15%(200 ml)- 15 min after an inhaled short-acting beta 2 -agonist [Diagnostic] | |
| 2. CBC(Complete blood count) | Usually normal | Eosinophilia in atopic asthma, Neutrophilic leucocytosis-if associated with RTI(Respiratory tract infection) | Eosinophilia in atopic asthma, Neutrophilic leucocytosis-if associated with RTI |
| 3. Total serum IgE | Increased in atopic asthma | Increased in atopic asthma | Increased in atopic asthma |
| 4. Allergen-specific IgE | Increased in presence of specific allergen in blood in allergic asthma | Increased in presence of specific allergen in blood in allergic asthma | Increased in presence of specific allergen in blood in allergic asthma |
| 5. Sputum for cytology | Increased count of Eosinophil in atopic asthma | Increased count of Eosinophil in atopic asthma | Increased count of Eosinophil in atopic asthma |
| 6. Skin prick test | Positive in allergic asthma and negative in nonatopic asthma | Positive in allergic asthma and negative in nonatopic asthma | Positive in allergic asthma and negative in nonatopic asthma |
| 7. Chest X-ray(P/A view) | Usually normal | Usually normal | May show hyperinflated lung fields, pneumothorax and lobar collapse |
| 8. High-resolution CT (HRCT) | Usually normal | Usually normal | May show areas of bronchiectasis in lungs |
| 9. Arterial blood gas analysis | Usually normal | Usually normal , Pa CO 2 may be increased and Pa O 2 may be decreased | Pa CO 2 increased and Pa O 2 decreased |
Complications of asthma:
1.Respiratory failure
2.Pneumothorax
3. Lobar collapse
4.Pigeon chest
5.Growth retardation in children
6. Cor- Pulmonale.
Lifestyle modification for prevention of asthma:
- Avoid allergens (eg, dust,pollens,smoke,cosmetics,dirty clothes or carpets,prawn, brinjal etc) to prevent asthma if you have allergy to these.
- Practice breathing exercises/yogasana (physical postures)/ pranayama (breath slowing techniques)/dhyana (meditation) for 65 minutes daily.
Diet in Asthma:
- Decrease dietary intake of antioxidants (found in fresh fruit)
- Take more margarine and polyunsaturated fatty acid
- Eat less butter and oily fish.
