INFLAMMATORY DISEASES-I -ASTHMA

ASTHMA

ASTHMA a tracheobronchial  inflammatory disease in which air flow restrictions happen due to bronchospasm results in wheezing,breathing difficulty,cough and cold.Of the two types of asthma namely allergic and non allergic the allergic type is more common which 95% of the people suffer.

In many cases of asthma increased numbers of inflammatory cells such as eosinophils,lymphocytes and macrophages are found to be present in the alveolar fluids.These are not found much in the alveolar lavage of the normal individual.These inflammatory cells are even found in the asthmatic person's broncho alveolar lavage who's lung function is at normal baseline and no recent asthma exacerbations.These inflammatory cells are found in both allegic and non allergic asthmatic patients.

Hence asthma is purely an inflammatory disease. 
Causes of Asthma  
1.Inflammation of the bronchial wal
2.Constriction of the bronchial smooth muscle
3.Increased mucus secretions
Clinical symptoms
Shortness of breath
coughing
Wheezing
Use of accessary muscles of respiration such as mouth breathing
Chest tightness
Precipitators of Asthma
Allergens  
These agents stimulate mast cells to release various inflammatory agents like histamins,leucotriens,and chemotactic factors that promote bronchiolar spasm and thickening of the
 mucus.
Infections  
Like viral upper respiratory infections exclusively in children in whom commonly these infections precipitate asthma.
Psychological factors 
These factors like stress and other confused states may cause asthma but not readily recognizable 

Treatments

The treatment options are as follows and fortunately all the available asthma treatment options described below are safely and aggressively can be used for pregnant ladies without any harm.

1.Sympathomimetic agents 

Mostly beta-2 adrenergic agonists are more suitable in this class of drugs as they are powerfully dilating the bronchial trunk by increasing cyclic Adinosine Monophosphate (cAMP)

(e.g)Pirbuterol;

        Terbutalin

        Albuterol and

        Salmeterol

These medicines can be safely administered by inhalation and because heir absorption in the systemic circulation is poor and hence side effects are minimal

These are the drugs of choice to get immediate releif from an acute attack as the onset of their action is quick.

Side effects Tremor and tachycardia.

2.Corticosteroids

Steroids reduce inflammations by reversing mucosal edema,by decreasing the capillary permiability and they inhibit the release of inflammatory agents such as leucotrienes,and cytokines.

Corticosteroids can be used both acute and chronic asthma.Since corticosteroids are not broncho dilators and hence a bronchodilator also must be included in the treatment regimens.

For acute exacerbations systemic steroids should be given via oral or i.v. routes followed by a maintenance therapy by inhalation.

(e.g.) 1.Beclomethasone

          2.Flunisolide

          3.Triamcinolone

          4.Fluticasone.

Side effects

Inhaled steroids may sometimes produce cough,oral thrush and dysphonia

Systemic steroids like prednisone can cause glucose metabolism defects,increased hungry;weight gain;hypertension,adrenal deficiency

3.Anticholinergics

Anticholinergics can cause bronchodilation and decreased mucosal secretions by blocking cholinergic nervous system. 

(e.g.) Ipratropium (Atrovent) is the best example in this class of anti asthmatics.

Uses 1.Asthma

         2.Chronic Obstructive Pulmonary Disease (COPD)

Side effects

1.Dry mouth

2.Sedation

3.Blurred vision

4.Urinary retension

5.Constipation. 

Because of inhalation many of the above side effects may not be seen as the drug is poorly go into the circulation.

4.Leucotriene Inhibitors

They inhibit the formation of leucotrienes from ecosatetranoic acid (Arachidonic acid)

e.g. 1.Zileuton (Zyflo)

        2.Zafirlucast (Accolate)

They can be taken orally

These medicines are used for chronic maitenance therapy and should not be used for acute attacks.

Side Effects

1.Zileuton is causing liver damage

2.Zafirlukast-Allergy

5.Theophyllin

Similar to sympathomimetic agents this also causes bronchodilation by increasing cAMP level.It is also having anti inflammatory effect.

Drug interactions Serious drug interactions are observed if theophyllin is used concomitantly with cimetidine end erythromycin as the later medicines will increase the theophyllin plasma concentration by competitively inhibiting its metabolism by liver cytochrom 450 enzyme.

Side effects and symptoms of overdose

1.Tremor;2.Insomnia;3.G.I.distress.

6.Mast cell stabilizers

e.g.Cromolin and Nidocromil

Can be used for prevention

Side effects Cromolyn causes pulmonary edema,cough and wheezing

Nedocromil causes mouth bitterness 
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