Asthma is a condition in which the bronchi (tube-like structures that carry atmospheric air into the lungs) are hyperactive and undergo spasms due to various factors and become narrow resulting in obstruction to airflow.
Other factors contributing to airway blockage are swelling of the walls of the bronchi and collection of fluid in the cavity of the bronchi.
Asthma in children varies in severity from occasional mild episodes to frequent severe attacks requiring hospitalization and seriously interfering with normal life. Occasionally it may even be life-threatening.
Why do some children have such hyperactive airways? Modern medicine has not been able to answer this question. Genetic factors may play a role.
Asthma is prevalent all over the world. Many factors trigger an asthmatic attack. Respiratory infection, dust, smoke, exercise, animal dander, some foods and stress are all known to induce an attack. Some drugs can also precipitate an attack. Well known drugs are aspirin and NSAIDs (Non-Steroidal Anti Inflammatory Drugs).
An asthmatic attack causes obstruction to the flow of air through the airways. The obstruction is caused by swelling of the mucous membrane, contraction of the muscles and by accumulation of inflammatory fluid inside the airways. As the air ways are quite small in children the obstruction to air flow can be quite severe. Click here to know about the structure of the bronchi.
Clinical features: The onset of asthma can be sudden or gradual. Usually following some cough or cold the child may experience a sense of tightness in the chest and experience difficulty in breathing. He starts breathing faster and the chest may cave in when the child tries to breathe in. This is called chest retraction and is common in young children.
A wheeze may be heard without any aid. Wheeze is a sound produced when air is expelled through the constricted airways. The increased resistance to air flow is responsible for the sound. This can be easily demonstrated by blowing air through tubes of different diameters.
In severe attack child may become irritable or drowsy due to decreased oxygen supply to brain. Bluish discoloration of skin (cyanosis) can occur in very severe asthma. This is because of accumulation of hemoglobin devoid of oxygen.
Management of asthma in children: As the seventy and frequency of attacks vary from one child to the other treatment has to be individualized.
Children with infrequent mild attacks can be managed with bronchodilators (a bronchodilator is a medicine which causes relaxation of the bronchial muscles and hence widening of bronchi) using a nebulizer or inhaler and antibiotics when indicated during the attack.
A nebulizer is a device which converts liquid medication into a mist that is driven by a compressor. It can be used either with a mouth piece or a face mask. The latter is more suitable for young children.
An inhaler is a device which contains multiple doses of a bronchodilator. One dose is delivered when the inhaler is pressed once. Inhalers can be used in older children if they can learn how to coordinate their breathing while pressing the inhaler.
For younger children a device called spacer can be used with a mask. One end of the spacer is attacked to an inhaler. When the inhaler is pressed the medicine collects in the spacer and the child can inhale the medicine through the mask.
If for some reason nebulizer or inhaler cannot be used bronchodilators can be given orally if the attack is mild. Commonly used oral bronchodilators are beta-2 agonists like salbutamol, terbutalize and orciprenaline.
The beta 2 agonists are drugs which act on receptors on the bronchial muscle and reverse the spasm of the muscles which cause narrowing of the airways. These receptors are called beta 2 receptors.
Those with frequent attacks require daily medication to ensure near normal life. The available drugs are anti-inflammatory drugs, long acting bronchodilators and leukotriene inhibitors.
As pointed out above inflammation also contributes to the narrowing of airways. During an attack some chemicals which cause inflammation of the bronchial wall are released. These chemicals act on the blood vessels resulting in leakage of fluid into the cavity of the bronchi and swelling of the mucous membrane of the bronchi.
Corticosteroids suppress the inflammation and hence play an important role in the management of asthma. Systemic steroids (orally administered or given by injections) can cause serious adverse effects and are reserved for those with severe asthma.
Inhaled steroids are far safer and are widely used in the treatment of asthma in children. Commonly used steroids are Beclomethasone, Budesonide and Fluticasone. Inhalers containing these drugs are available. These drugs are also available in combination with long acting beta-2 agonists. This combination is very effective in the management of moderate and severe asthma.
Another device used to deliver asthma medicines is a Rotahaler. It consists of two parts which can be detached. A capsule called rotacap containing the drug is inserted into the device and the upper part of the device is turned so that a projecting part inside the Rotahaler cuts through the capsule.
The drug collects in the lower piece of the rotahaler and can be inhaled. As the drug remains in the lower chamber the child can inhale several times till the drug is completely inhaled. Thus there will be no wastage unlike in an inhaler. Both beta 2 agonists and corticosteroids are available as inhalers and rotacaps.
Long acting beta 2 agonists used for asthma in children are Salmeterol and Formeterol, They are available as inhalers and rotacaps. Combination preparations of a long acting beta 2 agonist and a steroid are available-for example Formeterol with Budesonide and Salmeterol with Fluticasone.
Other oral drugs: As inflammation plays an important role in asthma attacks lot of research has been done to find out suitable anti-inflammatory drugs. During an asthma attack certain substances called leukotrienes are released.
These substances are responsible for the inflammatory response which leads to swelling of the mucous membrane, increased secretions and constriction of the bronchial muscles. Hence drugs which block the actions of leukotrienes help in preventing asthma in children.
Montelukast is one such drug which is beneficial in preventing asthma attacks. It is available as tablets, chewable tablets and granules for young children. It is not useful for treating an attack. The drug may not be very useful if used singly but when used in conjunction with inhaled corticosteroids with or without beta 2 agonists it does reduce the frequency of attacks.
Histamine is another substance which is released during asthma attacks and is responsible for the inflammatory reaction. Hence drugs which block the actions of histamine are also used in preventing asthma in children.
Ketotifen is an antihistamine which is useful is some children. Please do not confuse this with Ketoprofen which is a non steroidal anti inflammatory drug (NSAID) and can precipitate an asthma attack.
Exercise induced asthma: Some children develop an asthmatic attack after doing exercise. This may be prevented by the use of a short acting beta 2 agonist about 15 minutes before starting exercise. Regular use of long acting beta 2 agonists may also prevent exercise induced asthma. Other drugs used for this are sodium cromoglycate and nedocromil.
Other measures: As asthma in children can be triggered by many factors it is necessary to adopt a multi-pronged strategy to control asthma.
Dust: If dust is causing asthma every effort should be made to minimize exposure to dust. Vacuum cleaning should be used instead of sweeping. Wearing of masks is another useful practice.
Pets: Often a pet animal is the culprit. It may be a bit difficult to convince a child to part with his pet animal.
Stuffed toys and pillows can also cause asthma in children. Cigarette smoking is certainly harmful. A child may be exposed to passive smoking.
Psychological problems: Mind has profound influence on the body. Psychological problems are also believed to predispose to asthma. Hence sufficient attention should be given to psychological health of children.
Yoga: Some yogasanas are claimed to benefit asthmatic patients. While definite proof may not be available children and adolescents with asthma should be encouraged to practice yogasanas as they are certainly good for general health.
Skin testing may help in identifying the allergen in some patients but is not helpful in all patients.
High humidity is another risk factor. Hence asthmatic patients should avoid going to places with high humidity.
It is better to avoid carpets and upholstered furniture. Any respiratory infection should be promptly treated as infection can trigger asthma in children. Gastro-esophageal reflux also predisposes to asthma and should be identified and treated.
Diet: There is no specific diet for asthma in children. If any food is precipitating an attack it should be avoided. Parents should ensure that children get a healthy diet containing all the vitamins and trace minerals. Anti-oxidants are believed to help in controlling asthma. It is better to avoid foods containing preservatives, artificial colors and flavors as far as possible.