Diagnosis of Asthma in Infants/Children

Long-term management decisions begin with diagnosis and an appreciation for factors that may influence the prognosis for asthma in children.

DIAGNOSIS OF ASTHMA

0–4 Years of Age: The Expert Panel recommends that essential elements in the evaluation include the history, symptoms, physical examination, and assessment of quality of life. A therapeutic trial with asthma medications will also aid in the diagnosis. Several studies show that as many as 50–80 percent of children who have asthma develop symptoms before their fifth birthdays. Diagnosis can be difficult in this age group and has important implications.

On the one hand, asthma in early childhood is frequently underdiagnosed (receiving such inappropriate labels as chronic bronchitis, wheezy bronchitis, reactive airway disease (RAD), recurrent pneumonia, gastroesophageal reflux, and recurrent upper respiratory tract infections). Therefore, many infants and young children do not receive adequate therapy. On the other hand, not all wheeze and cough are caused by asthma, and caution is needed to avoid giving infants and young children inappropriate prolonged asthma therapy.

Episodic or chronic wheeze, cough, and breathlessness also may be seen in other, less common, conditions, including cystic fibrosis, vascular ring, tracheomalacia, primary immunodeficiency, congenital heart disease, parasitic disease, and foreign-body aspiration. Diagnosis is complicated by the difficulty in obtaining objective measurements of lung function in this age group.

5–11 Years of Age: The Expert Panel recommends that the diagnosis in children 5 years of age and older should follow the same procedures recommended below.

Diagnosis of Asthma in Infants/Children

Consider a diagnosis of asthma and performing spirometry if any of these indicators is present.*

These indicators are not diagnostic by themselves, but the presence of multiple key indicators increases the probability of a diagnosis of asthma. Spirometry is needed to establish a diagnosis of asthma.

1. Wheezing—high-pitched whistling sounds when breathing out—especially in children. (Lack of wheezing and a normal chest examination do not exclude asthma.)
2. History of any of the following:
• Cough, worse particularly at night
• Recurrent wheeze
• Recurrent difficulty in breathing
• Recurrent chest tightness
3. Symptoms occur or worsen in the presence of:
• Exercise
• Viral infection
• Animals with fur or hair
• House-dust mites (in mattresses, pillows, upholstered furniture, carpets
• Mold
• Smoke (tobacco, wood)
• Pollen
• Changes in weather
• Strong emotional expression (laughing or crying hard)
• Airborne chemicals or dusts
• Menstrual cycles
4. Symptoms occur or worsen at night, awakening the patient.

• Hyperexpansion of the thorax, especially in children; use of accessory muscles; appearance of hunched shoulders; and chest deformity.
• Sounds of wheezing during normal breathing, or a prolonged phase of forced exhalation (typical of airflow obstruction). Wheezing may only be heard during forced exhalation, but it is not a reliable indicator of airflow limitation.
• Increased nasal secretion, mucosal swelling, and/or nasal polyps.
• Atopic dermatitis/eczema or any other manifestation of an allergic skin condition.

• Allergic rhinitis and sinusitis
• Obstructions involving large airways
• Foreign body in trachea or bronchus
• Vocal cord dysfunction
• Vascular rings or laryngeal webs
• Laryngotracheomalacia, tracheal stenosis, or bronchostenosis
• Enlarged lymph nodes or tumor
• Obstructions involving small airways
• Viral bronchiolitis or obliterative bronchiolitis
• Cystic fibrosis
• Bronchopulmonary dysplasia
• Heart disease
• Other causes
• Recurrent cough not due to asthma
• Aspiration from swallowing mechanism dysfunction or gastroesophageal reflux

• Additional pulmonary function studies (e.g., measurement of lung volumes and evaluation of inspiratory loops) may be indicated, especially if there are questions about possible coexisting COPD in adults, a restrictive defect, vocal cord dysfunction (VCD), or possible central airway obstruction. A diffusing capacity test is helpful in differentiating between asthma and emphysema in patients, such as smokers and older patients, who are at risk for both illnesses.
• Bronchoprovocation with methacholine, histamine, cold air, or exercise challenge may be useful when asthma is suspected and spirometry is normal or near normal. For safety reasons, bronchoprovocation testing should be carried out by a trained individual in an appropriate facility and is not generally recommended if the FEV1 is less than 65 percent predicted. A positive methacholine bronchoprovocation test is diagnostic for the presence of airway hyperresponsiveness, a characteristic feature of asthma that also can be present in other conditions (e.g., allergic rhinitis, cystic fibrosis, COPD, among others). Thus, although a positive test is consistent with asthma, a negative bronchoprovocation may be more helpful to rule out asthma.
• Chest x-ray may be needed to exclude other diagnoses.
• Allergy testing may be needed to identify environmental triggers.
• Biomarkers of inflammation. The usefulness of measurements of biomarkers of inflammation (e.g., total and differential cell count and mediator assays) in sputum, blood, urine, and exhaled air as aids to the diagnosis and assessment of asthma is currently being evaluated in clinical research trials.
• Recurrent episodes of cough and wheezing are due most often to asthma in both children and adults. Underdiagnosis of asthma is a frequent problem, especially in children who wheeze when they have respiratory infections. These children are often labeled as having bronchitis, bronchiolitis, or pneumonia even though the signs and symptoms are most compatible with a diagnosis of asthma. The clinician needs, however, to be aware of other causes of airway obstruction leading to wheezing.
• Cough variant asthma. Although chronic cough can be a sign of many health problems, it may be the principal—or only—manifestation of asthma, especially in young children. This has led to the term "cough variant asthma." Monitoring of PEF or methacholine inhalation challenge, to clarify whether there is bronchial hyperresponsiveness consistent with asthma, may be helpful in diagnosis. The diagnosis of cough variant asthma is confirmed by a positive response to asthma medication. Treatment should follow the stepwise approach to long-term management of asthma.
• Vocal cord dysfunction (VCD) often mimics asthma. VCD is characterized by episodic dyspnea and wheezing caused by intermittent paradoxical vocal cord adduction during inspiration (sometimes with abnormal adduction during expiration as well). The cause of VCD is not well understood, although some patients develop VCD in response to irritant triggers, such as fumes, cold air, and exercise. Although VCD is clearly distinct from asthma, it is often confused with asthma, leading to inappropriate medication of affected individuals with anti-asthma medications. Asthma medications typically do little, if anything, to relieve symptoms if the patient has pure VCD. VCD should be considered in the differential of difficult-to-treat, atypical asthma patients. It is important to note, however, that VCD and asthma may coexist and that VCD may complicate asthma management. Elite athletes, in particular, are prone to both exercise-induced bronchospasm (EIB) and VCD, so careful workup is warranted for athletes who present with exercise-related breathlessness. During severe VCD episodes, respiratory distress may be severe and lead to intubation. Once the trachea is intubated, the wheezing and distress abate in VCD but not in asthma. VCD can be difficult to diagnose. Variable flattening of the inspiratory flow loop on spirometry is strongly suggestive of the diagnosis, but abnormalities of the inspiratory loop may well be absent between episodes. The diagnosis of VCD comes from indirect or direct vocal cord visualization during an episode, during which the abnormal adduction can be documented. Therapy generally consists of speech therapy and relaxation techniques
• Several conditions that may coexist with asthma can complicate diagnosis: allergic bronchopulmonary aspergillosis (ABPA), obstructive sleep apnea (OSA), and gastroesophageal reflex disease (GERD).