DefinitionIt is a syndrome characterized by AIRFLOW OBSTRUCTION that varies markedly, both spontaneously and with treatment.Narrowing of the airways is usually reversible, but in some patients with chronic asthma there may be an element of irreversible airflow obstruction

pathologically by bronchial inflammation with prominent eosinophil infiltration physiologically by bronchial hype-reactivity, and clinically by variable cough, chest tightness and wheeze

EpidemiologyIt affects approximately 10-15% of children and 5-10% of adultsPrevalence is greater in industrialized countriesPrevalence is increasing world-wide

Pathology of asthmaInfiltration with inflammatory cells (esp. eosinophils and T-lymphocytes)Patchy epithelial sheddingAirway smooth muscle thickeningSubepithelial fibrosisMucus gland and goblet cell hyperplasiawidespread mucus plugging in fatal asthma

Mechanisms of asthmaInflammation underlies airway hyperresponsivenessThe inflammation is of characteristic pattern and it involves interaction between many inflammatory cellsThis results in the release of multiple inflammatory mediatorsInflammatory mediators result in bronchoconstriction, mucus secrition, exudation of plasma and airway hyperresponsiveness

Neural mechanism may amplify the asthmatic inflammationStructural changes may occur with subepithelial fibrosis, airway smooth muscle hyperplasia and new vessel formation. These changes may underlie irreversible airflow obstruction

Types of asthmaAllergic (extrinsic) asthmaNon-allergic (intrinsic) asthmaOccupational asthmaAspirin induced asthma Asthma of infancy(

Allergic asthmaOnset usually in childhoodMay persist into adulthoodRemission in adolescence is commonAssociated with allergic rhinitis and atopic dermatitis in variable combination

Intrinsic asthmaOnset in adultsNo external inciter is recognizedOften associated with perennial non-allergic rhinitisAccounts for approx. 10% of adult asthma

Occupational asthmaDue to exposure to chemical sensitizers at workUnrelated to atopic statusSome occur in atopics due to allergen exposure at work

Aspirin induced asthmaSpecial type of intrinsic asthmaIt is a metabolic, pharmacological disorderacute asthma attacks on first and subsequent exposure to aspirin and NSAID

Asthma of infancyRecurrent bouts of significant airflow limitation in small airways from viral infectionsOften remits as child gets oldernot associated with atopySometimes called wheezy bronchitis

Clinical features

Symptoms TriggersPhysical signs

SymptomsWheeze-- intermittent, worse on expiration, chracteristically relieved by an inhaled 2- agonistCough-- usually unproductiveChest tightnessSOB Prodromal symptoms may precede an attack

TriggersAllergens (house dust mite, pollen, animal dander, moulds)Irritants (tobacco smoke, air pollutants, strong odours, fumes)Physical factors (exercise, cold air, hyperventillation, laughter, crying)Upper respiratory tract viral infectionsEmotionsOccupational agents (chemical sensitizers, allergens)Drugs (beta blockers,NSAID)Food additives (metabisulphite,tartrazine)Change in weatherEndocrine factors (menstrual cycle, pregnancy,thyroid disease)

Physical signsExpiratory ronchi- widespreadHyperinflation of chestUse of accessory musclesAssociated signs: nasal polyps, flexure eczema

DD in adultsMechanical obstruction of airwaysCOPDHeart failurePEVasculitidesCarcinoid syndrome with hepatic secondaries

Principles of treatmentEducate patients to develop a partnership in asthma managementAssess and monitor severity with objective measurement of lung functionAvoid or control asthma triggersEstablish medication plans for chronic managementEstablish plans for managing exacerbationsProvide regular follow-up care

Clinical evaluation of severityNumber of daytime attacks lasting more than 24 hrs and needing extra medicationThe presence of completely symptom-free intervals lasting more than 4 weeks without medicationThe frequency of waking at night due to asthma symptomsThe amount of absence from work or school because of asthmaThe ability of the patients to keep up with peers in normal physical activityThe number and type of medications required on regular basisThe frequency of using extra relief medications on an as needed basisThe frequency of hospital admissionThe of life-threatening episodes

MEDICATIONS

SteroidsBeta-agonistsCromolynMethylxanthinesLeukotriene modifiersAnticholinergics

CORTICOSTEROIDSProven most effective benefit for chronic controlInhaled form preferredInhibit inflammatory cell migration and activationDecrease airway responsivenessReverse beta-receptor down regulationImprove spirometry

CORTICOSTEROIDSSide effects include thrush, cough, dysphoniaDexamethasone not includedRisks for children and growth suppression not an issueUsed for any classificationSystemic steroids reserved for severe

CROMYLYN/NEDOCROMILAnti-inflammatory effect from blockage of chloride channels for mast cellsHelp inhibit allergy response and exercise responseProven to improve improve peak flow and reduce beta-agonist useDosage usually 4 times per daySafety well knownLess predictable response than corticosteroids

LONG ACTING BETA AGONISTSNot to be used for acute exacerbationsDirectly stimulates beta receptors to relax bronchial smooth muscleEspecially useful for nocturnal symptomsStudies show that tolerance does not developCan cause tachycardia, hypokalemia, prolonged QT interval

METHYLXANTHINES? Mechanism but does provide mild bronchodilationNot the preferred chronic therapy Numerous adverse effects, risk of toxicity, drug interactions, and lab monitoring

LEUKOTRIENE MODIFIERS

Use in children not widely approvedFew side effects-reported liver effectsDrug interactions with theophylline, warfarin, terfenadineOral formulations once dailyWork to decrease leukotrienes and decrease inflammationStudies mostly on mild asthma-improves sx and increase peak flow

QUICK RELIEF DRUGSShort acting beta-agonist work within 30 minutesAll asthma patients should have this availableAnticholinergics can give relaxation of bronchial smooth muscle-no role in long term management

STEPWISE APPROACH

Severe PersistentHigh dose corticosteroidLong acting bronchodil.Oral steroidsModerate PersistentAnti-inflammatoryLong acting bronchodil.Mild PersistentAnti-inflammatory orLeukotriene modMid IntermittentNo daily medications

Asthma is a chronic inflammatory disorder of the airway which manifest by symptoms such as episodic breathlessness, wheezing, chest tightness and cough particularly at night and the early morning.

Inflammation makes the airways sensitive to stimuli such as allergens, chemical irritation, tobacco smoke cold air or exercise.

Bronchial asthma is one of the most common chronic disease, is of all asthmatic patients suffer from chro nic symptoms recuiri continuous administration of anti asthmatic drugs.

Chronic asthma is the asthma for which we should give continuous and cautions treatments in drily clinical practice.

Chronic asthma is characterized by : Clinically : recurrent episodes of dyspnea and wheezing caused by reversible airway narrowing. 2. Physiologically : increased airway responsiveness. 3. Pathologically : by inflammation of the airway Eo infiltration and damage to the airway epithelioma.4. Immunologically : increased Ig eproduction.

Ask patients : Dose the patients have ;Reccurent attacks of wheezing Cough or wheeze at night?Cough or wheeze after exercise Cough, wheeze of chest tightness of exposure to allergens or pollutants

Classive severity of asthma : Step I: INTERMITTEN Step II: MILD PERSISTENT Step III : MODERATE PERSISTENT Step IV : SEVERE PERSISTENT

1. QUICK RELIEF SABA ANTI CHOLENERCKSSHORTACTING THEOPHYLLIN ADRENALIN INJECTION 2. LONGTERM PREVENTIVE Corticosteroid Soding cromoglycate Nedocromil LABA Sustained released theophylline Ketotifen

Monitoring the course of asthma :

Review of symptoms Measurement of lung function as much as possible Long-term peak flow monitoring for patients with persistent asthma is important for providing objective measurement of the course of the disease.

THE BEST way to stop asthma attacks is presentation. Identify and avoid triggers eg : Domestic dust mites Animal allergens Tobacco smoke Cackroach Rold Smoke Cold Physical activity

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