Bronchial Asthma ( Causes - C/P - Investigations - Treatment )

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Bronchial Asthma ( Causes - C/P - Investigations - Treatment )

Bronchial Asthma

Def. Asthma is an inflammatory disease of airways that is characterized by ­­ responsiveness of the tracheobronchial tree to a multiplicity of stimuli, characterized by paroxysmal attacks of dyspnea and wheezy chest.
Cause:
Extrinsic asthma:(Atopic)
Characterized by
1- Early childhood (early onset asthma)
2- + ve. F.H. of atopy

urticaria hay ever
3- IgE ­­
¯
Ag + IgE à mast cell à¯
release of mediators à bronchospasem
4- prognosis à good due to (Natural desensitization)
Types of Ag
1- Pollens 4- Dust
2- Animal dander 5- Mites
3- Drugs e.g. penicillin, Cephalosporines 6- foods
Intrinsic: (mostly non allergic)
Characterized by: 1- Age > 40 years
2- -ve Family History. (for atopy)
3- Ig A ­­ in some cases
4- prognosis not good.
Other types of asthma:
1- Aspirin sensitive . Aspirin inhibits P.G synthesisà­­ production of leukotrienes from arachidonic Acid, this is common in patient with nasal allergy and nasal polyps.
2- Exercise induced, asthma due to thermal changes within bronchial tree (Cooling and drying of bronchial mucosa)
3- Occupational e.g. Byssinosis, spray painting, bakers, varnishes.
4- Allergic bronchopulmonary Aspergillosis à Aspergillus Ab. in serum.
5- Cough variant asthma.
6- Chest infection due to respiratory syncytial virus.
7- Stress induced asthma.

Pathogenesis of asthma (A topic)
1- Ag. - Ab. over mast cell à mediators
2- Eosinophils à release O2 radicals, and major basic protein.
3- T lymphocytes à release interleukin-5.



C/P During attacks
Dyspnea + wheezy chest

O/E harsh vesicular, breathing. + rhonchi - signs of emphysema or hyperinflated chest

In between. Attacks

à free

Investigation:
1- X-ray à there is no diagnostic features of asthma on the chest X ray but it may be helpful in excluding pneumothorax.
2- Blood gases (during attacks)
☺mild cases à wash of Co2 due to hyperventilation so Co2 ¯
☺sever cases à hypoventilation so Co2 either normal or ­­
3- skin hypersensitivity test.
4- Blood Ig E à extrinsic
Ig A à intrinsic
eosinophilia
aspergillus Ab
5- Sputum: * Churchman’s spirals
= mucous that form a cast of the small airway.
* Charcot laden crystals
= breakdown products of eosinophils
Metacholine, histamine test indicates the presence of non specific bronchial hyper-reactivity à bronchospasm at lower dose in asthma.
Cold air challenge (i.e. inhalation of cold air à bronchospasm)

Treatment of Bronchsopasm during attack

Inhaled beta 2 – specific sympathomimetic

No response Good response
¯¯
40-60 mg methyl continue therapy, discharge,
prednisolone /6 hrs injection and arrange for follow up &
¯ treat as below
No response
¯
Anticholinergic inhalers
A minophyline injection

Scheme for treatment of bronchospasm in patients
(in between attacks) with stable disease

Occasional use of inhaled short acting B2 agonist bronchodilator

*Step 1

à

Regular inhaled B2 agonist as required + beclomethasone inhaler 800 mcg twice daily.

*Step 2

à

High dose inhaler (800- 2000 mcg/d) + B2 agonist

*Step 3

à

As step 3+ Aminophyline oral or B2 agonist oral or anticholinergic inhaler.

*Step 4

à

As step 4+ oral steroids in the lowest dose that control symptom (single daily dose)

*Step 5

à

Treatment of bronchial asthma: à (drugs used in treatment of bronchial asthma)

I- During attacks
A- inhalers MDI (metered dose inhaler)
Salbutamol (ventoline)
= B2 agonist
¯
bronchodilator
Advantages à No side effects of systemic B2 agonist
Rapid action
Dose: 2 puffs then, 1-2 puffs /20 m till improvement (100 ug/puff)

B- Aminophylline I.V.
Dose: Loading dose: 5mg/kg (very slowly) maintenance dose
­ in acute sever asthma: 0.5 mg/kg/hr.
N.B. = old age, heart disease, liver diseases௯ dose of
Aminophylline
= Smokers & phenytoin à­­ dose of Aminophylline.
C- Cortisone: à Hydrocortisone (rapid action) 100-300 I.V.
Action: reduce airway obstruction

anti - inflammatory antiallergic
D- Adrenaline: the patient must be

non hypertensive non cardiac patient
Dose: solution (1/1000 - amp. lml)
0.5 ml. à S.C. it can be repeated after 20-30 minutes


II-In between Attacks:

A- Aminophylline
The best is long acting preparation 200 mg/12 hr.
= Quibron (Anhydrous Aminophylline)



Dose: 1/3-1/2 tab. /12 hr.
Advantages: Less GIT irritation, long acting.
Mechanism: inhibits phosphodiasterase enzymeà­ action of C.A.
through ­ the level of C.A.
B- B2 agonist: (bronchodilator)
* Salbutamol ventoline
Salbuvent
* Terbutaline Bricanyl
* Side effects Tremors
Tachycardia (palpitation)
* Dose 2-4 mg/D
C- Inhalers (Disodium cromoglicate [intal]):
stabilizes the membrane of mast cell
¯
¯¯ release of mediators
D- Ketotifen:(zaditen)
• Like Intal but oral (mast cell stabilizer)
Dose : 1 mg tab / 12 hrs
Q : Mediators of bronchial asthma :
Histamine, Bradykinies, P.G., leukotrienes platelets
activiating factos.
E- Bisolvon: dissolve secretion (tab. 1 x 3)
F- Cortisone:
a- Local inhalers Becotid) = Beclomethazone
Dose: 2-3 puffs/d (250 ug per puff)
Side Effects: oropharyngeal candidiasis, To avoid we can wash the mouth by water after use.
b- Systemic steroids: à prednisolone
Dose: 30- 40 mg/d à till improvement then low dose maintenance 5 - 10 mg/d


III. Treatment of status asthmatics:

Def. status asthmaticus Is a severe form of asthmatic attack which is prolonged & not responding to usual therapy. = (Acute severe asthma)
1- Hospitalization.
2- O2 therapy.
3- Aminophylline • loading dose 5mg/kg
• maintenance 0.5 mg/kg/hr
4- Hydrocortisone à 200 mg I.V/6 hrs for 24 hrs. then prednisolone 60 mg/d orally for 2 weeks, then gradual withdrawal then we can use steroid inhaler.
5- Bisolvon à amp. I.M. à to dissolve secretions.
6- Fluids à to overcome dehydration and dissolve secretion.

N.B • we can give B2 agonists by nebulizer, (5 mg/4 hrs)
• We can mix B2 agonists + normal saline & inhaled over
5-15 minutes.

7- Bronchial lavage à to dislodge the viscid secretion.
8- Ventilator à indication when Co2 ­­ = bad sign
(I.e. hypoventilation)
9- Ab. for infection
Sedatives are contraindicated as à R.C depression with hypoventilation.

Other measures in treatment of bronchial asthma
1. Anticholinergic (Ipratropium Bromide) inhaler.

2. Avoid Ag if possible.

3. systemic desensitization: by gradual S.C injection of small doses of Agàto form Ig.G (blocking Ab) so when Ag introduced once more it well be attacked by Ig G and not by Ig E.

4. Tryptizole small dose 10 mg/d.


Tricyclic Antidepressant sedative

anticholinergic
5. Methotrexate: low dose may be useful in management of steroids dependent asthma allowing reduction in steroid dose.

Signs of severe asthmatic attacks
1- Tachycardia >120/m.
2- Exhaustion
3- Pulsus paradoxius.
4- Silent chest (No rhonchi)
5- Cyanosis, pt can’t speak
6- Dehydration due to hyperventilation
7- O2 ¯ - Co2 ­
8- Peak expiratory flow < 60% of the expected value by peak flow meter.

Source: Internal Medicine Book of Dr.Osama Mahmoud (Ain Shams University)