REACTIVE AIRWAY DISEASE: CAN I USE THE TERM?

Frequently one finds the diagnosis written on discharge cards as “reactive airways” and “reactive airways disease”. Perhaps what the physician wanted to convey is a diagnosis of asthma. The terms though highly nonspecific are increasingly used more so by pediatricians. Diagnosing asthma in early childhood is difficult and the tests for asthma especially the lung function tests are not accurate before the age of six years. Thus in such situations describing the clinical condition as reactive airway disease has become a common practice.

Asthma is defined as hyper responsive airways and Reactive Airway Disease (RAD) is also used denote conditions in which the airways (bronchi) in the lungs overreact to certain things. Often the term “reactive airway disease” is used when asthma is suspected but not yet confirmed. It is usually applied when a child presents with the constellation of symptoms of coughing, wheezing or shortness of breath. Asthma also usually presents with these symptoms. The features of asthma in children vary from child to child with some children presenting only with night time cough. In children asthma may present with any of the following symptoms:

• Frequent coughing spells, which may occur during play, at night, or while laughing or crying
• A chronic cough (which may be the only symptom)
• Less energy during play
• Rapid breathing (intermittently)
• Complaint of chest tightness or chest "hurting"
• Whistling sound when breathing in or out — called wheezing.
• See-saw motions in the chest from labored breathing. These motions are called retractions.
• Shortness of breath, loss of breath
• Tightened neck and chest muscles
• Feelings of weakness or tiredness.

Though these signs signify asthma, they may also be the presenting symptoms of other childhood respiratory illness. Diagnosis of asthma is difficult in children as the definitive tests like spirometry need the child’s cooperation. It is very rare that patients have had measurement of airway reactivity to methacholine, histamine, or hypertonic saline. Infants with repeated attacks of symptoms attributable to asthma like wheezing with shortness of breath or cough will outgrow their symptoms by 6 years of age. Yet half of them would proceed to be classified as asthma in later life. Which of the children would continue to have symptoms is difficult to predict. Because of this dilemma most pediatrician use the term RAD in early life. Subsequently if the child is cooperative then s/he would be subjected to the definitive tests.

Airway hyperreactivity is an important component of the diagnostic criteria for asthma. When the airways are described as hyper reactive , it implies that they exhibit a bronchconstictor response to substances at doses that normally have no bronchoconstrictor effect . Airway hyperreactivity includes both airway sensitivity and airway hyperresponsiveness. While airway hyperreactivity is characteristic of asthma and chronic obstructive pulmonary disease in an adult , it is also described in patients with allergic rhinitis without asthma, cystic fibrosis and even in irritable bowel syndrome. Thus airway hyperreactivity is a highly specific term with definite meaning. It implies a physiological abnormality rather than a diagnosis.

Brooks in 1985 first used the term reactive airway dysfunction syndrome (RADS) to describe asthma like illness in adults after a single exposure to high levels of irritant vapors, smoke and fumes. These patients have methacholine hyperrectivity but other pulmonary function tests are usually normal. In patients with RADS the symptoms can persist for years even after a single exposure. RADS differs from asthma in that there is no prior sensitization of the airways. RADS is recognized as a distinct disorder by the American Thoracic society and American College of Chest Physicians.

Diagnosis of asthma is established when one documents reversible airway obstruction or airway hyperreactivity.  Labeling a patient as “reactive airways disease” reflects the inability of the physician to confidently establish the diagnosis of asthma. This is usually the case in children in whom “reactive airways disease” could mean wheezy bronchitis, viral bronchiolitis , pneumonia or asthma.

In children asthma can begin at any age. Risk factors for the development of asthma include low birth weight, low socioeconomic status, black ethnicity, frequent respiratory infections, exposure to tobacco smoke before or after birth, nasal allergies and family history of allergies.

Children with asthma should always be kept away from all sources of smoke. Avoiding triggers, using medications regularly and evaluating daily for symptoms before it becomes a full blown attack are the ways to control asthma in children of all ages. Proper use of medication that is the right medicine in the right dose at the right time is the basis of good asthma control. Inhaled steroids may be key to managing infants with chronic asthma or wheezing which would include RAD other than asthma also. Once a person’s airways become sensitive, they remain that way for life. Though they may remain symptom free if the allergen is avoided for life. About 50% of children experience a noticeable decrease in asthma symptoms by the time they become adolescents, therefore appearing to have "outgrown" their asthma. About half of these children will develop asthma symptoms again as adults.