If the child's asthma is not well controlled on 400 mcg a day of beclomethasone or 200 mcg a day of fluticasone, then what should be the course of action? It is best to add a drug that has an additive effect with inhaled steroids. There are 3 such classes of drugs:

• Long-acting b2 -agonists.
• Leukotriene receptor antagonists
• Theophylline.

The most effective of these in school children, are the long-acting 2 -agonists. However, there are no trials in pre-school children. Although there is less strong evidence in support of using leukotriene receptor antagonists, there are studies in pre-school children. So this is the drug that can be used as add-on therapy in the child under the age of four or five. Theophylline is less effective. We have less data regarding its efficacy particularly during exacerbations. Also, it has a high risk of side effects. Therefore, long-acting 2 -agonists and leukotriene receptor antagonists are preferable to theophylline as add-on therapy.

 

The adolescent group with asthma is a difficult group to handle. Teenagers tend to be difficult and usually have problems getting along with others. From the medical point of view, the consequences of this in a teenager with asthma are:

• Underdiagnosis
• Undertreatment
• Increased risk of death.

 

The risk of death in a 15- to 20-year-old with asthma is six times more than that in a 5- to 10- year-old. Given the risk-taking behaviour of the teens, many children with asthma tend to take up smoking like their disease-free fellow teenagers. In the UK, this behaviour is more in girls. Girls grow into women and women have children. The impact of tobacco smoking is so much that if a normal child takes up smoking there is a more rapid decline in lung function in adult life. If a severe asthmatic takes up smoking, that effect is more dramatic and superimposed on an already abnormal lung function. (Fig. 20)

• Airway inflammation and consequent deterioration in lung function occurs in early childhood.
• Allergen exposure aggravates the progression of asthma.
• Passive and active smoking has additional adverse effects on lung function.
• Diagnosis is usually made on the basis of history but may require trial treatment.
• Low dose inhaled steroid treatment is ideal for children with persistent symptoms.
• Add-on therapy should be tried before increasing inhaled steroid dose above 400 mcg (beclomethasone).
• Better communication leads to better compliance.
• If asthma is attacked early in childhood, with the right treatment, then children can lead a happy life and progress to normal adulthood.

 

No, it is not a useful test in the diagnosis of asthma. There is no doubt that if you have airway inflammation the level of nitric oxide in your exhaled breath goes up. If you undergo treatment with inhaled steroids the level goes down. But that is a general statement. There are children with severe asthma who have normal levels of nitric oxide. There are people with respiratory infections who have high levels of nitric oxide but do not have asthma at all. So it can at best be a supplementary aid to diagnosis. It may not be sensitive or specific for use in routine management, even if we can afford the equipment and persuade the children to use it.

 

Yes, nitric oxide is one and eosinophil cation protein is another. But they are neither sufficiently sensitive nor specific to be used in clinical practice. Ultimately, airway inflammation can be determined only by bronchoalveolar lavage or bronchial biopsy, which is not advocated in routine practice.

 

There is no good non-invasive method of assessing ongoing airway inflammation in children. The non-invasive methods that have been used such as exhaled nitric oxide, the products of eosinophils, and so on are not sufficiently reliable to use in clinical practice.

So in the case of the child who becomes completely and genuinely asymptomatic (including full range of exercise tolerance), first reduce the dose of inhaled steroids and then stop it. If asthma returns over the next few weeks, it will indicate that airway inflammation persists. Then restart inhaled steroids. Parents in general will agree because they would have seen the consequences of stopping it.

 

The basis of the hypothesis is that an exposure to microbes, bacteria or virus, in early life may have a protective effect against the development of asthma. During development, certain types of TH-1 and TH-2 cells are produced. TH-1 cells are directed towards infection while TH-2 cells produce chemical compounds related to allergy. In early life, there is an option to go either way towards TH-1 or TH-2. The theory is that if you are exposed to a lot of something in bacteria or virus, that drives you towards the infective type of response and protects you from allergens.

Children who get a lot of viral infections in early life seem to be protected from getting asthma. Children who are youngest in a large family or children who go to the crÅche or nursery at a very early age are exposed to these infections. That is the first piece of evidence.

The second piece of evidence shown by some studies is that if you have a pet at home in the first year of life, that seems to have a protective effect against the development of asthma. The theory is that, microbes that the pet brings with it override the risk of developing allergy to the pet. The stronger evidence coming from six different countries is that children brought up on a farm and who live very close to farm animals during the first year or two of life are very less likely to develop asthma. It is on account of exposure to something in animals. The hygiene hypothesis suggests that it is exposure to dirt but more likely due to exposure to microbes around the place. We are not sure what is in those microbes. The current hypothesis is that it is endotoxin.

 

There are very important differences. Indeed, most asthma in adults starts at childhood. The most important difference is that, paediatricians get an opportunity to treat asthma before airway remodelling or airway inflammation becomes chronic. Paediatricians have the opportunity to diagnose it first and see the early stages of asthma.

There are other important differences too. Childhood asthma is changing all the time. As children grow, some outgrow their asthma, while in some others it becomes worse. The triggers are also different.

Children are more active than adults. So exercise- and activity-induced triggers are more important and have a greater effect on quality of life compared to adults.

Pre-school children experience more viral upper respiratory tract infections than adults. In children, these are major triggers of asthma attacks whereas in adults they are not.

 

Yes, but not very well. Theophylline given in low dosages regularly has some anti-inflammatory effect and some bronchodilatory effect. But it is very much a second choice and not to be used unless there are very good reasons or better options available.

 

There is a lot of work done on this by S. McKenzie in London, UK. It was concluded that less than 10 percent of pre-school children had cough. Rest of them would have wheeze which their parents might know or would be diagnosed by the doctor through provocation. The provocation in a pre-school child is to make him run up and down and then listen to the chest. While cough variant asthma is very uncommon it does exist.

 

The child is thriving, cough occurs only at night and with exercise, but is not productive with purulent sputum. There is no other diagnosis. The doctor should then observe if the cough goes away with asthma treatment.

 

The important answer is that if one uses a dose too high for the severity of asthma, then one may get growth suppression. If the dosage is appropriate according to the severity of asthma, then there is very little risk of growth suppression.

 

Judgement should be made about treatment every two months. If the child becomes asymptomatic on inhaled steroids, reduce the dose. Once the dose becomes the lowest possible and the child remains asymptomatic, stop the drug. If symptoms return and the parents agree that the child needs treatment, restart medication.

There is no place for immunotherapy in practice.

 

Some will come off permanently, because in some children asthma remits spontaneously. There is, unfortunately, no way of predicting this. So when the child becomes asymptomatic wean them off treatment and see if asthma comes back.

 

If high dose nebulised bronchodilator is used for acute asthma in a child under the age of five, there is a possibility that the oxygen saturation may fall. If a high dose of salbutamol is given by spacer, this does not happen. In general practice, it is better to carry a spacer rather than a nebuliser when going on visits.

 

One can give inhaled steroids at the age asthma is diagnosed. And one can even diagnose asthma in infancy provided the symptoms are frequent and severe enough to justify treatment.

There is no bottom age limit but one must assess the frequency and severity of symptoms, and other associated features that may suggest that asthma will persist. But inhaled steroids can be started in a child of just six months if these criteria are met.