Management of asthma Asthma is a reversible airways obstruction in which sensitization and inflammation play an important role. There are two phases, initial phase mediator-induced bronchospasm, followed by a second or late phase ( 6 to12 hours later ) which is believed to be a manifestation of the inflammatory response being more refractory to b\ds treatment than the initial phase, corticosteroids give a better effect. Management of asthma Asthma is a reversible airways obstruction in which sensitization and inflammation play an important role. There are two phases, initial phase mediator-induced bronchospasm, followed by a second or late phase ( 6 to12 hours later ) which is believed to be a manifestation of the inflammatory response being more refractory to b\ds treatment than the initial phase, corticosteroids give a better effect.

Clinically, asthma is divided into extrinsic and intrinsic. Extrinsic asthma is a manifestation to immunologic reactivity to environmental agents. Patients with this type give a history of atopy, onset during childhood or adolescence, seasonal occurrence, and response to environmental stimuli. Intrinsic asthma occurs in the third or fourth decade of age, there is no identifiable extrinsic allergen associated with the asthmatic attack.

Principles of MT : The goals of therapy are to prevent attacks and effectively reduce hyperresponsiveness in patients who suffer attacks. Before initiating therapy, it is important to verify that wheezing is not due to a non- asthmatic cause such as pulmonary oedema, embolism, foreign body or infection. Principles of MT : The goals of therapy are to prevent attacks and effectively reduce hyperresponsiveness in patients who suffer attacks. Before initiating therapy, it is important to verify that wheezing is not due to a non- asthmatic cause such as pulmonary oedema, embolism, foreign body or infection.

MT of acute attacks and chronic active disease : Most patients with acute asthmatic attacks can be managed as on an out- patient basis, provided that therapy is promptly and properly instructed. Most of the patients seeking ER care do not need parenteral therapy. Most of them presented to ER they have no available medication, relied on over- counter, preparations, used fixed combination tablets or suppository forms that do not permit proper dosing

Anti- inflammatory therapy ( AIT ) : Gluco- corticosteroids, cromolyn and nedocromil now emerge as the corner-stone of treatment, with bronchdilators relegated to an adjunctive role. All patients with active disease should started and maintained on continuous AIT and B\Ds should be used only for symptomatic relief of mild acute exacerbations and for prevention of post-exertional flares. Anti- inflammatory therapy ( AIT ) : Gluco- corticosteroids, cromolyn and nedocromil now emerge as the corner-stone of treatment, with bronchdilators relegated to an adjunctive role. All patients with active disease should started and maintained on continuous AIT and B\Ds should be used only for symptomatic relief of mild acute exacerbations and for prevention of post-exertional flares.

Glucocorticosteroides are AIT of choice in most adults with asthma. Their action is 6 to 12 hours after administration. The inhaled preparations ( beclomethasone, triamcinoline, flunisolide ) are preferable to oral therapy because systemic absorption is minimal and hence steroids adverse effects are eliminated. Although highly effective, oral and parenteral systemic glucocortcoids ( prednisone, methylprednisalone, hydrocontisone ) should be reserved for refractory cases and used for a short period. Their prolonged daily use side effects are osteoporotic fractures, adrenal suppression, skin changes, aseptic necrosis of bone and aggravation of diabetes mellitus. Glucocorticosteroides are AIT of choice in most adults with asthma. Their action is 6 to 12 hours after administration. The inhaled preparations ( beclomethasone, triamcinoline, flunisolide ) are preferable to oral therapy because systemic absorption is minimal and hence steroids adverse effects are eliminated. Although highly effective, oral and parenteral systemic glucocortcoids ( prednisone, methylprednisalone, hydrocontisone ) should be reserved for refractory cases and used for a short period. Their prolonged daily use side effects are osteoporotic fractures, adrenal suppression, skin changes, aseptic necrosis of bone and aggravation of diabetes mellitus.

Inhaled glucocorticoids, topically active have got the advantage of long steroid therapy without systemic side effects. The principal metered- dose – inhaler ( MDI ) preparations include beclomethasone dipropionate ( vanceril, beclovent ), flunisolide ( aerobid ), and triamcinoline ( azmacort ), they can be used up to 20 puffs \ day. Tapering dose should be considered when switching from prolonged systemic oral steroids to MDI,to prevent adrenal suppression. Oral thrush and hoarseness are sometimes problems with prolonged use of MDI, but can be prevented by rinsing and gargling with water after each dose or by using a spacer. The onset of action is within 2 to 8 hours and their response lasts 6 to 8 hours. The daily dose is 2 to 4 doses, but in refractory cases up to 20 puffs \ day may be used, then reduced gradually as the condition improves.

Prednisone 5 mg, half – life 12 to 24 hours, a short term course 7 to 10 days, beginning with a high dose ( 40 to 60 mg \ day ) and rapidly tapering dose is optimal for control of a severe acute attack that is refractory to all other measures, only patients with chronic disabling bronchospasm refractory to all measures should be considered as candidates for long – term daily systemic steroid therapy. Prednisone 5 mg, half – life 12 to 24 hours, a short term course 7 to 10 days, beginning with a high dose ( 40 to 60 mg \ day ) and rapidly tapering dose is optimal for control of a severe acute attack that is refractory to all other measures, only patients with chronic disabling bronchospasm refractory to all measures should be considered as candidates for long – term daily systemic steroid therapy.

Beta-agonists : The selective inhaled beta-agonistsare the b\ds for treatment of asthma, because of their relative selectivity for bronchial beta-receptors, their rapid onset of action ( 2 to 5 min. ) when taken as MDI, sustained duration of action ( up to 6 hours ) and paucity side effects. Albuterol ( provventil, ventolin ), metapioterenol ( aluperit, metraprel ), bitolterol ( tornalate ), terbutaline ( brethine, bricanyl ) and pributerol ( maxair ) are the main drugs in this class. Most of them are available in both oral and inhalation forms, terbutaline is available in s\c injections. Inhaled forms are preferred because of rapid onset and less systemic side effects. Oral terbutaline may cause troublesome tremor. Albuterol is a reasonable choice for most patients requiring an inhaled semiselective beta- agonists.

Theophylline and its derivatives : The methylxanthines ( theophylline & aminophylline ) were the first orally active b\ds. Their role has become limited as faster, safer, more effective therapies,beta-agonists have been developed. The theophyllines low cost, clearly measured therapeutic range ( gm\ml ) and availability of sustained-release preparations facilitate their utilization. They help patients bothered by nocturnal exacerbations, and they can reduce systemic steroid requirements in some patients with refractory disease. Adverse effects are proportional to their serum level with levels > 20gm\ml associated with a marked increase in risk of toxic side effects. When levels > 35gm\ml, life-threatening ventricular arrhythmia can occur. Theophylline and its derivatives : The methylxanthines ( theophylline & aminophylline ) were the first orally active b\ds. Their role has become limited as faster, safer, more effective therapies,beta-agonists have been developed. The theophyllines low cost, clearly measured therapeutic range ( gm\ml ) and availability of sustained-release preparations facilitate their utilization. They help patients bothered by nocturnal exacerbations, and they can reduce systemic steroid requirements in some patients with refractory disease. Adverse effects are proportional to their serum level with levels > 20gm\ml associated with a marked increase in risk of toxic side effects. When levels > 35gm\ml, life-threatening ventricular arrhythmia can occur.

Anticholinergics : Ipratropium, a topically active muscarinic blocking agent similar to atropine, is available in MDI preparation. It is useful in COPD, but its efficacy is less in asthma.

Leukotriene receptor antagonists : These are drugs that inhibit leukotriene activity ( e.g. zileuton ). These agents show a possible future role in treatment of asthma. They achieve b\d and symptomatic improvement. Leukotriene receptor antagonists : These are drugs that inhibit leukotriene activity ( e.g. zileuton ). These agents show a possible future role in treatment of asthma. They achieve b\d and symptomatic improvement.

Prophylaxis: Once an acute attack subsides, the goal of MT shifts to prevention of episodes by : identification of the responsible allergen skin antigenic screening test and desensitization avoidance of the offending agents anti-inflammatory therapy, and reduction in dependence on chronic b\d treatment cromolyn sodium, the inhaled steroids, and prednisone are the important anti-inflammatory agents for prophylaxis teach the patient the proper use of PEFM, MDI, spacer ( spacehaler ) and breath-activated inhalers for persons who can not use MDI.

Choice of therapy : 1. Mild intermittent disease ( MID ) : Inhaled beta-adrenergics are the drugs of choice in MID and exercise-induced asthma. 2. Mild chronic disease ( MCD ) : Inhaled topical steroid is the treatment of choice. Nocturnal attacks can be prevented by a long-acting-controlled-release theophylline before bed time, serum theophylline levels should be monitored. 3. Acute disease : An inhaled beta-agonist ( e.g. albuterol 3 puffs 6 hourly ) is the Rx of choice. Those with bronchospasm that lessens but does not resolve within 24 hours are candidates for short, rapidly tapering course of oral steroids ( 7-10 days course of prednisone, starting with full doses mg\day ). Tapering should be followed by a course of inhaled steroid. 4. Chronic refractory disease ( CRD ) : Daily doses of oral corticosteroid, regular use of inhaled steroid ( 20 puffs \ day ) may be an effective alternative.

Monitoring therapy : Patients subjective assessment of severity, inspiration \ expiration ratio, PEFR, FEV1.0, pulsus paradoxus, sternocleidomastoid retraction are among the meaningful guides to assess the clinical status and severity of disease. Monitoring therapy : Patients subjective assessment of severity, inspiration \ expiration ratio, PEFR, FEV1.0, pulsus paradoxus, sternocleidomastoid retraction are among the meaningful guides to assess the clinical status and severity of disease.

Indications for admission : Some authors have developed an index to predict need for admission : Ps> 120\min, RR> 30\min, pulsus paradoxus > 18mm Hg, PEFR 120\min, RR> 30\min, pulsus paradoxus > 18mm Hg, PEFR< 120L\min, moderate to severe dyspnoea, accessory muscle use, and wheezing. Lacking more definitive means of prediction, clinical status and response to therapy remain the most helpful guidelines for decision making. Admission is indicated for those with an acute attack, who manifest one of the following : Lacking more definitive means of prediction, clinical status and response to therapy remain the most helpful guidelines for decision making. Admission is indicated for those with an acute attack, who manifest one of the following : 1. Subjective report of severe difficulty in breathing 2. Failure to respond fully and promptly to inhaled beta-agonist therapy that is followed promptly by full doses of prednisone. 3. Use of accessory muscles of respiration ( sternocliedomastoid retraction ) 4. Pulsus paradoxus > 10 mm Hg 5. FEVi.o < 1.0 L\sec 6. Arterial PCO2, inappropriately high for respiratory rate 7. Underlying cardiac condition 8. Inadequate home situation or a history of incompliance.