Asthma is a disease of the airway passages characterized by inflammation and narrowing of these airways in response to certain triggers which lead to difficulty breathing. Children's airways are narrower than those of adults so triggers that may cause only a slight response in an adult can be much more serious in children.
Mutasim Abu-Hasan, MD, pediatric pulmonologist at University of Iowa Children's Hospital, says children with strong family history of allergies or asthma are at increased risk of asthma. "We know that asthma runs in families due to genetic factors that are not yet well described. Also children exhibiting allergy symptoms such as allergic rhinitis (hay fever), atopic dermatitis (eczema), or allergic conjunctivitis (eye allergies) are at increased risk of developing asthma.
"In addition to allergies, viral infections seem to herald the onset of asthma in children. Severe respiratory synsycial virus (RSV) infection in infancy is a risk for later development of asthma symptoms especially with subsequent respiratory viral infections (colds). Finally, exposure to second hand tobacco smoke is associated with higher incidence of asthma symptoms and asthma diagnosis," he says.
The exact cause(s) of asthma in children are not known. "We know that asthma is triggered by different infectious and environmental factors. These triggers lead to inflammation and increased responsiveness of the airways (i.e. exaggerated bronchospasm). It is also widely accepted among researchers that allergic asthma develops in genetically predisposed children after timely exposure to environmental risk factors. Small airways in some children might be the reason for developing asthma symptoms during viral infections. So, it is a complex interplay between genes and environment that is not completely understood," Abu-Hasan says.
The Surgeon General recently released a warning about the affects of secondhand smoke. Abu-Hasan says children of smoking parents more likely to develop asthma. "Numerous epidemiologic studies support this statement. The risk for asthma increases with the number of adult smokers living with the child. More importantly, smoking during pregnancy interferes with lung growth of the fetus and increases the risk for asthma after birth as well as other serious health detriments.
A cough is the most common symptom of pediatric asthma, and may be the only symptom. Abu-Hasan says the asthma cough is typically worse at night. It starts as a dry cough and becomes productive after short period of time and can last for long time unless treated unlike coughs from a cold which are usually resolved in one to two weeks.
"More serious symptoms of asthma include wheezing, dyspnea (shortness of breath) and respiratory distress. The presence of such symptoms indicates narrowing of airway passages. If airway obstruction is very severe to the extent of impairing gas exchange, more ominous symptoms such as cyanosis (turning blue) or even loss of consciousness might occur.
"Several tests can be performed in children suspected to have asthma to support the diagnosis of asthma. This includes lung function testing which can detect airway obstruction due to bronchospasm. If no airway obstruction is detected, patient can be challenged with a known trigger of bronchoconstriction and see if it produces excessive response. Testing for allergies can also be done to detect the presence of allergies. Unfortunately none of these tests is a certain diagnostic of asthma. Diagnosis remains by large based on clinical judgment," he says.
Treatment of asthma consists basically of two groups of medications. One is directed towards relieving bronchospasm, called bronchodilators and usually given in an inhaled form. Albuterol is the most widely used drug of this sort and is commonly used to provide immediate relief from symptoms (i.e. rescue medications).
The second group is directed towards the airway inflammation, steroids being the most commonly used one of this group of medications. Oral steroid are usually given in short courses to treat asthma attacks. Inhaled steroids are given to control daily symptoms and prevent acute attacks in the future.
Not all children who develop asthma also have asthma as adults. "On the contrary," Abu-Hasan says, "the majority of childhood asthma improves or even completely subsides with age, especially viral induced asthma. Allergic asthma can continue during adolescence and adulthood."
Is the University of Iowa Children's Hospital involved in any research with regard to asthma in children?
Several important asthma related studies have already been done at University of Iowa Children's Hospital and the results of these studies have been published. There is also ongoing asthma research in both clinical and basic arenas attempting to improve diagnosis of asthma, better understand the mechanism of the illness, and test new therapies. |
