Vol. 14 •Issue 3 • Page 42
Asthma Care from Cradle to Preschool
Diagnosis and Treatment of Young Children Present a Special Challenge
Despite advances in therapy, pediatric asthma care remains a clinical challenge, particularly in the infant and child less than 5 years old.1,2 These challenges range from making an asthma diagnosis, to individualizing treatment, to assuring consistent access to medical care.
Few controlled studies of various asthma controller therapies’ indications and effectiveness in the very young child have been published. Yet, early diagnosis and treatment of asthma is important because uncontrolled symptoms are associated with significant morbidity and expense.
Direct care costs such as emergency department visits, hospitalizations and physician office visits are disproportionately higher for ages 0 to 4.3 Indirect costs to families are also a concern. Recurrent wheezing episodes can increase anxiety and reduce the quality of life for both the child and family. Although rare, there’s always a chance of death from asthma.
Many infants and preschool children will experience at least one episode of acute wheezing in the first years of life.1 The Tucson Children’s Respiratory Research study found that nearly 50 percent of young children wheeze before age 6, and roughly one-third of these young wheezers will have persistent asthma.4
Longitudinal cohort studies such as the Tucson study shed new light on the course of typical early childhood episodic wheezing.2,4-8 It’s now recognized that early childhood wheezing isn’t a single disorder, rather it’s a spectrum of distinct phenotypes.2,5-7
Three phenotypic categories are used to describe early wheezing and asthma in this select age group: transient early wheezing, non-atopic wheezing and atopic wheezing. Even though risk factors and characteristics for each group can overlap, these categories are important to consider for diagnosis, treatment and long-term prognosis.
TRANSIENT EARLY WHEEZING
Transient early wheezing is the most common phenotype representing 60 percent of all recurrent wheezing episodes in infancy and early childhood. It begins in the first year of life and usually resolves by age 3 to 6.2,4
There’s no strong association with either personal or family history of allergic sensitization.5 Wheezing episodes occur almost exclusively in association with viral respiratory infections.
Researchers have noted that a significant association exists between maternal tobacco smoking during pregnancy and exposed infants having lower lung function at birth. This difference persists into later childhood, suggesting an alteration of the lung has occurred in utero.9 Postnatal smoke and exposure also increases the risk of wheezing.
Other environmental risk factors for transient wheeze include: day care attendance in the first months of life, having older siblings at home, and exposure to house dust endotoxin and cockroaches.2,7,10,11 Male gender, being born to a younger mother, having lower birth weight, and being bottle fed have been associated with early transient wheezing.2
Non-atopic wheezing represents 20 percent of recurrent wheezing episodes in the first three years of life. Symptoms begin during the first year of life, and the risk for recurrent wheezing significantly decreases by age 10.5 There isn’t a strong personal or family history of atopy.
Viral lower respiratory infections, particularly with respiratory syncytial virus within the first two to three years of life, significantly increase the risk for wheezing in this phenotype. Research suggests that there may be both a genetic predisposition and an acquired bronchial hyper-responsiveness involved.2 Premature infants and infants who are formula fed in the first months of life seem to be at higher risk for non-atopic wheezing.
ATOPIC OR IgE-ASSOCIATED WHEEZING
Atopic or IgE-associated wheezing occurs in about 20 percent of children with episodic wheeze before age 3. About 80 percent of cases of atopic asthma begin during the first six years of life.2
Initial presentation may be exactly the same as the other two phenotypes. Wheezing usually starts a little later, typically during the second or third year of life. Symptoms may be more severe and can be triggered with or without viral respiratory infections. In the Tucson cohort, the atopic group showed significant lung deficits by age 6.2
There’s no single marker or test that clinicians can use to reliably distinguish viral-induced wheeze from atopic asthma in infants and preschoolers. Twenty-five percent of persistent wheezers had elevated IgE levels at 9 months old.2 Those likely to have persistent wheezing can have a blood eosinophilia of ³ 4 percent in the first year of life and may have a higher peripheral eosinophil response to viral infections.2,12,13 In a chart review, researchers found that 56 percent of children diagnosed with asthma younger than 3 years old had a positive hypersensitivity skin test to aeroallergens suggestive of atopy.1
The child with atopic asthma is four times more likely to have a positive family history of asthma and two to three times more likely to have a personal history of atopic dermatitis.2,7,14 Many atopic wheezers have allergic rhinitis.
MAKING A DIAGNOSIS
Pulmonary function testing to confirm the presence of reversible airway obstruction isn’t commonly available for the child less than 5 years.15-18 The diagnosis of asthma in young children must be based on symptom and medical history, physical examination, the exclusion of alternative diagnoses, and response to treatment.
A recent study found that parents incorrectly recognize wheezing 41 percent of the time.19 Recognition of wheezing can be improved by asking the parents to provide a clear description of what they call wheezing and demonstrating to them the medical signs and symptoms of wheezing.2
Other causes for acute wheezing exist besides asthma, and the younger the child, the greater the likelihood that an “alternative” diagnosis exists.18,20 The differential diagnosis of typical vs. atypical wheezing requires consideration of:
• Timing: First episodes of typical wheezing start at 2 to 5 months old and are usually associated with viral respiratory infections. If the onset of wheezing begins at birth or soon afterward, one should suspect atypical wheezing due to conditions such as congenital airway malformations, heart disease or cystic fibrosis.2 Acute first-time wheeze in a 2- to 5-year-old child is suspicious for foreign body aspiration.
• Pattern: The typical wheezing pattern is one of short recurrent exacerbations of cough and wheeze of varying severity and duration separated by long symptom-free intervals. Most exacerbations are induced by viral respiratory infections. Wheezing continuously for weeks is suspicious for an underlying atypical problem. Consider gastroesophageal reflux if recurrent vomiting occurs with or just after feeding together with airway symptoms.
• Severity: Most typical wheezy infants have mild, intermittent airway obstruction. Continuous, unremitting symptoms should arouse suspicion of atypical or alternative causes. Cyanosis, with or without feeding, or apnea suggest an atypical cause of airway obstruction.
• Physical examination: Failure to thrive (weight below the fifth percentile or crossing down more than two major percentile lines over time) usually denotes cystic fibrosis or some other serious underlying condition.
Typical wheeze is a high-pitched, musical or polyphonic sound and heard during expiration. Monophonic, nonmusical inspiratory sounds could occur with laryngeal stridor such as from tracheomalacia or impingement from vascular rings. Digital clubbing, an abnormal cardiac or neurological examination, or asymmetry of the chest should raise suspicion of an alternative diagnosis.
EFFECTIVE DELIVERY OF THERAPY
All children who have recurrent wheezing and a positive bronchodilator response should have access to a short-acting bronchodilator to use for acute symptoms. It’s important that the child’s caregivers understand when to use a “rescue” bronchodilator such as albuterol, how to deliver it effectively, and how to judge whether it’s helping.
A metered dose inhaler can be used in the young child with a valved holding chamber with face mask. I have often encountered families of young children who mistakenly have been given a spacer with a mouthpiece, told to just use the MDI mouthpiece, or think the spacer is to be used with only one type of inhaler. Of course, even a very young child can hold a mouthpiece like they can a drinking straw, but there’s less delivery to the airways. Inhaled delivery using a nebulizer is also popular though it’s less portable and more time-consuming.
Studies comparing the two delivery systems show similar effectiveness when using good technique. For both methods, a good seal with the face mask is important to assure optimal drug delivery. “Blow-by” treatments without a mask or with a poor seal can result in loss of half or more of the medication being delivered.21
Crying reduces delivery of inhaled medication to the lungs.22 Tips to address child cooperation with inhaled treatments include having the child “practice” taking a treatment using the mask without medicine. Start with very short times and hold the mask while counting. Use verbal praise and stickers as a reward. Try a distraction such as a book, song, video or toy. If the child cries or pulls the mask off, stop the activity. Don’t talk or restart until crying stops. Parents must practice using these techniques and be patient.
DAILY ASTHMA CONTROLLERS
The Tucson Children’s Respiratory Study showed a loss of pulmonary function between 1 and 6 years old in atopic asthma.5 The researchers suggested that it may be prudent to treat infants who are at high risk for persistent asthma early in order to change the natural course of the disease.20 Multiple studies show that use of inhaled corticosteroids provide good asthma control in older children and adults; however, there are few studies in children younger than 4.2,23
In 2002, the National Asthma Education and Prevention Program (NAEPP) Expert Panel provided updated recommendations for long-term control therapy for children age 5 and younger.14,24 The NAEPP report specifies that long-term controller therapy should be considered in young children who have:
• more than two asthma episodes per week requiring treatment and/or
• more than three episodes of wheeze in the past year with risk factors for asthma and/or
• experienced severe exacerbations of asthma less than six weeks apart.24
The NAEPP preferred controller treatment for mild persistent asthma in those 5 years and younger is a low-dose inhaled corticosteroid. Alternative therapies are inhaled cromolyn or an oral leukotriene receptor antagonist. For those with moderate persistent asthma who report daily symptoms or nocturnal symptoms more than one night per week, preferred treatment is either a low-dose inhaled corticosteroid together with a long-acting inhaled beta2-agonist or a medium dose of inhaled corticosteroid.24 These recommendations are based on expert opinion and extrapolation from studies in older children.
Clinical researchers have proposed treatment algorithms for infants and children 2 to 6 years old that are more aggressive than the NAEPP 2002 criteria.2 Their algorithms distinguish between children with an atopic or a non-atopic background, and treatment steps are based on the frequency of acute wheezing episodes. They recommend that young children with an atopic background and at least two wheezing episodes be given a trial of two to three months of inhaled corticosteroid.
Further research is needed to define who may benefit most from controller therapy. Little is known regarding the long-term safety of inhaled corticosteroid in the young child, although data in older children suggest that low doses are safe.2,23-26 The delivered doses of inhaled medication may differ in younger children due to variances in swallowed fraction, ventilation and cooperation. If a poor response is observed, remember I-C-E (check inhaler technique, compliance and environmental control) and to consider other diagnoses.
ESTABLISHING A PARTNERSHIP
Asthma care needs to be a partnership between the patient, family and clinicians.5,24 Good communication with a clear plan for when to call and how to initiate a change in therapy can help assure treatment is started early with acute illness and that asthma control is optimized.
All families should be given a written action plan. The action plan should include what to do every day to control asthma, what to do for acute symptoms, and when to seek emergency medical treatment. Include contact and follow-up appointment information.
Ask directly about the caregiver’s ability to read and his or her preferred language. For those with low literacy, use pictures like smiley and sad faces and color codes for medications.
At follow-up visits, ask about use of the action plan and medications, address any concerns the family may have, and check inhaled delivery technique. These actions will help make “well asthma visits” meaningful for families.
ENCOURAGE PREVENTATIVE BEHAVIORS
Remember to counsel families on preventative measures they can take to reduce the likelihood of asthma symptoms. Children over the age of 6 months with asthma should be given an annual influenza vaccine. Good hand washing is important in infection avoidance, and even young children can be taught.
All children should be in a smoke-free environment. Ask about exposure to tobacco smoke at each visit. Explain that tobacco smoke is an irritant that also can make it easier for other things to trigger asthma.
Encourage parents to quit smoking. Clinical practice guidelines are available to assist you in providing smoking cessation counseling and using pharmacotherapy.27 The National Cancer Institute offers a smoking quit line, (877) 44U-QUIT, to answer smoking-related questions in English or Spanish. The American Lung Association’s Freedom From Smoking program is available at www.lungusa.org.
Diagnosis and treatment of asthma in infants and children less than 5 years old remains a special challenge for clinicians. In managing infants and preschoolers with recurrent wheeze, clinicians must consider information obtained from their patient’s medical and family history, symptom history, physical exam and diagnostic assessment.
Infants less than 2 years old have a high probability of having their recurrent wheezing resolve between ages 3 and 6 and never develop asthma (transient early wheezing). Those infants who have a personal or family history of atopy have a greater likelihood of having persistent asthma that will continue into childhood and beyond (atopic asthma).
Preventing complications of asthma requires timely detection and diagnosis, tailored treat-ment, and patient and family self-management education.
Dr. Sockrider is a pediatric pulmonologist and an associate professor at Baylor College of Medicine, Houston. She is clinical director of the Children’s Asthma Center at Texas Children’s Hospital, Houston.
For a list of references, please call Mike Bederka at (610) 278-1400, ext. 1128, or visit www.advanceweb.com/respmanager.