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| Asthama |
Asthama
DEF#chronic imflamatory disease of airway charcterised by an increased responsiveness of tracheobronchial tree to variety
of stimuli.
Manifest as paroxysm of dyspnoea,cough,wheezing as result of musclespasm,mucosal oedema,&bronchial secreations.
CLASSIFICATION#
1.Erly onset asthama(atopic,allergic,extrinsic)
2.Late onset asthama(non-atopic,intrinsic,idiosyncratic)
ETIOPATHOGENESIS#
2major factors.
1.Bröchial hyperresponsiveness
2.Inflamatory reaction in bronchial wall
3.Roll of allergans
PATHOGENESIS_
cell triggers
[ [
Mediators___>bronchial
[ hyperresponse
] |
Inflamation |
| |
|_Symptoms__|
CELLS INVOLVED inreleas mediator
¤Mast cells¤macrophages
¤eosinophil¤lymphocytes
MEDIATORS
¤histamine¤prostaglandins(d2,f2,E2)¤thrombaxane¤PAF¤bradykinin
¤leucotrienes(B4,C4,D4,E4)¤subP
¤adenosine¤oxygen radicals
TRIGGERS
¤exercise¤hyperventilation
.¤cold air¤dust & fumes
¤respiratory viral infection
¤emotional stress¤tobaco smoke
¤aspirin,beta blockers
CLINICAL FEATURES
discussed under 3 headings
1.EPISODIC ASTHAMA
¤occurs in episodes with asymptomatic period between
¤spontaneos in onset triggered
by allergans,exerecise,viral infe
2.SEVERE ACUTE ASTHAMA
also called
status asthamaticus
symptoms persist instid of initial
Rx¤severe dyspnoea,unproductiv
cough
¤Signs-sweating,central cyanosis
tachycardia,pulsus paradoxus
3.CRONIC ASTHAMA
chronic cough with mucoid sputum,¤episodes of cough&wheeze during night
PHYSICAL SIGN IN CHEST
seen onely during attack
1.Tachycardia use of accesory
muscles of respiration
2.Percussion,Hyper-resonant
3.Breath sonds-vesicular
4.Rhonchi&wheeze
5.Silent chest airflow insufficient
to produce rhonchi
INVESTIGATIONs
1.Chest radiography
in attck lungs r hyperinflated
complications like pigeon chest,
lobar/segmental collapse may occur
2.Pulmonary function tests
forced expiratory volume in 1min
[FEV1] vital capacity[VC],peak
expiratory flo rate[PEF]
3.Arterial Blood Gas analysis
it shows hypoxia&hypocarbia
4.Skin hypersensitivity test for
allergans & there avoidance
5.Blood& sputum for eosinophilia
#MANAGEMENT#
3 broad headings
A].Avoidance of allergans
B] .Desensitisation imunotherpy
C].Drugs therapy
A].Avoidance of allergans
it is possible when there is single allergan
.B].Desensitisation
repeated S.C inj of extract of
allergans
.C].Drugs
seven catagories of drugs r use
1}.BETA-ADRENERGIC AGONISTS
b1=heart b2=bronchial smoothmu
¤adrenaline_dose0.3-0.5ml of1:1000 sol route-sc ripeated at
interval of 20minutes
¤salbutamol
dose2-4mg tds oraly/2puff 100ug
¤salmeterol
2puffs of25 ug each2/3timeday
¤formeterol
2puffs of6 ug each1/3times day
2}.METHYL XANTHINES
¤theophylline
dose:100-200mg tds 300mg bds
or450-600mg od
¤aminophylline
dose:loading 5mg/kg slowly ouer
20minute.Maitenance:0.5mg/kg/hr
3}CORTICOSTEROIDS
¤hydrocortisone
dose loading-4mg/kg iv followed
by2-3mg 6 hourly
¤prednisolone
40-60mg oraly single mornig dose
¤beclomethasone (200ug) budesonide(200ug),
4}CHROMONES
¤nedocromil sodium
route-inhalation 4mg2/4time
5}.ANTICHOLINERGICS
¤ipratropium bromide
2puffs of20ug each time 4/day
6}LEUKOTRIENE INHIBITORS
¤zafirlukast 20mg 4times a day
¤montelukast10mg once day
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