Bronchial asthma which is often referred to as Asthma is caused by irritation of the airways.

When irritation of the airways occur, the airways contract and hence the width of the respiratory passages decrease and they get filled with secretions causing respiratory difficulty.This inflammation reduces the amount of air flowing through the air passages and cause violent respiratory efforts.

Etiology of bronchial asthma

There are many factors which can trigger an asthma attack,house dust,pollen,cotton dust,cobwebs etc. are some allergens which trigger an attack of asthma.Asthma can also be triggered by exercise, stress, tobacco soke, cold etc.

Children are the most susceptible for asthma.Some children get spontaneous remission in the 11-14 age group.The explanation given is that,as the child grows the child’s immune system gets adapted to the great number of allergens it comes across.

Most of the children affected will have a family history of asthma or atopy.They will have skin manifestations like contact dermatitis, eczema etc.

Mechanism

Allergens like pollen cause degranulation of mast cells.When mast cells degranulate, histamine gets released.Histamine causes the airway mucosa to swell and smooth muscles in the bronchiolar walls to contract causing symptoms of asthma.Histamine also causes local irritation and causes accumulation of secretions in the airway causing further irritation.

Clinical features

Cough

Shortness of breath

Chest tightness

Wheeze

Intercostal retraction

Tachycardia

In severe asthma the wheeze may be audible without a stethoscope. There maybe bluish tinge to lips and tongue(cyanosis) due to increased carbon dioxide(carboxy hemoglobin) in blood.

Investigations

Spirometry

Lung function tests

Chest Xray

Allergen assay

Blood investigations

Treatment

1.Beta 2 agonists like salbutamol,terbutaline etc. are used in emergency management of bronchial asthma.These drugs helps in dilating the bronchial pathways thus allowing more air to pass through.
Salbutamol is available in the form of nebulization and tablets.
In emergency situations salbutamol nebulization is given.

2.Anticholinergic drugs -Ipatropium,Thiotropium

These drugs are given as nebulization along with beta 2 agonists.These drugs help in reducing secretions and help in relieving the bronchial muscle spasm.

3.Steroids- Steroids like dexamethasone are the mainstay of management for bronchial asthma.Steroid reduce the inflammation of the airways and give immediate relief.

For long term treatment of asthma a combination of a long acting beta 2 agonist(terbutaline) and a steroid is usually given.

4.Lekotriene antagonists -Monteleukast and Zafirleukast

5.Inhibitors of mast cell degranulation- Chromolyn sodium.These drugs are mainly used for the treatment of seasonal asthma triggered by pollen, cotton dust etc.

Precautions to be taken

Since dust is the major cause of asthma, frequent cleaning of rooms to avoid accumulation of dust is needed.

Window panes should remain shut during spring season when pollen grains disseminate.

Using of face masks while travelling on motorbikes is a necessary precaution to avoid triggering of asthma due to exhaust fumes.

Compliance and regular use of inhaled drugs as per the advice of the physician.