Asthma

Asthma: Excerpt from The 5-Minute Pediatric Consult

Lee J. Brooks, MD

Asthma - BASICS

Asthma - description

• Characterized by 3 components:
  • Reversible airway obstruction
  • Airway inflammation
  • Airway hyperresponsiveness to a variety of stimuli
• Diagnosis (the 3 “R”s)
  • Recurrence: Symptoms are recurrent.
  • Reactivity: Symptoms are brought on by a specific occurrence or exposure (trigger).
  • Responsive: Symptoms diminish in response to bronchodilator or anti-inflammatory agent.

• Pitfalls:
  • Not recognizing that asthma can manifest as chronic cough; wheezing may not be evident
  • Reluctance to “label” child with having asthma (using terms such as reactive airways disease or bronchitis)
  • Frequent antibiotic or cough medicine use to treat asthma symptoms
  • “Recurrent pneumonias” often are actually asthma exacerbations; subsegmental atelectasis on chest x-ray misdiagnosed as an infiltrate
  • Underreporting of asthma symptoms; beware the child who “doesn’t like to play sports”; he/she may have learned that exercise causes dyspnea
  • Poor adherence with therapy when symptoms are controlle
  • Failure to use inhaled medications properly: Inhaled medication use must be taught and reviewed at each visit. A fixed-volume holding chamber should always be used with a pressurized metered-dose inhaler (pMDI), regardless of patient age. pMDIs should be refilled based on the number of doses used, not by estimating contents by shaking or spraying.

Asthma - epidemiology

Asthma - incidence

• Most common chronic illness in children
• Death from asthma in children more than tripled from 1979 to 1996, but has been decreasing since then, perhaps due to better recognition and increased use of anti-inflammatory medications. The incidence of death from asthma does not seem to correlate with severity.

Asthma - prevalence

• Wheezing in children is extremely common in the industrialized world (cumulative prevalence, 30–60%).
• In younger children, most episodes occur following viral infections.
• >50% of children who wheeze in early childhood stop wheezing by age 6 years.
• 14% of all young children (40% of those who wheeze during infancy) continue to wheeze.

Asthma - risk factors

Asthma - genetics

• Children of asthmatics have higher incidence of asthma.
  • 6–7% risk if neither parent has asthma
  • 20% risk if 1 parent has asthma
  • 60% risk if both parents have asthma
• Several genes are known to be associated with the development of atopy and bronchial muscle responsiveness.

Asthma - pathophysiology

• Immune and inflammatory responses in the airways are triggered by an array of environmental antigens, irritants, or infectious organisms.
• Atopy and asthma are related.
  • Eosinophilia and the ability to make excess IgE in response to antigen is associated with increased airway reactivity.
  • Asthma is more common in children who have allergic rhinitis and eczema.
• Viral infections, particularly respiratory syncytial virus (RSV), during infancy may play a role in the development of asthma or may modify the severity of asthma.
• Exposure to cigarette smoke and other airway irritants influences the development and severity of asthma.
• Airway is stimulated and primary inflammatory mediators released.
• Airway is invaded by inflammatory cells (mast cells, basophils, eosinophils, macrophages, neutrophils, B and T lymphocytes).
• Inflammatory cells respond to and produce various mediators (cytokines, leukotrienes, lymphokines), augmenting the inflammatory response.
• Airway epithelium is inflamed and becomes disrupted, and basal membrane is thickened.
• Airway smooth muscle is hyperresponsive, and bronchoconstriction ensues.
• Airway smooth muscle hypertrophy and airway epithelial hyperplasia are characteristic chronic changes resulting from poorly controlled asthma.

Asthma - DIAGNOSIS

Asthma - signs & symptoms

Asthma - history

• Inquire about these symptoms: Coughing, wheezing, shortness of breath, chest tightness:
  • Frequency of symptoms defines severity.
  • Precipitating factor (trigger)
  • Response to bronchodilator or anti-inflammatory medication
  • Family history of asthma or atopy
• Pattern of symptoms:
  • Perennial versus seasonal
  • Continuous versus acute
  • Duration and frequency of episodes
  • Diurnal variation/nocturnal symptoms
• Do any of the following set off the breathing difficulty?
  • Infections (upper respiratory, sinusitis)
  • Exposure to dust (mites), animal dander, pollen, mold
  • Cold air or weather changes
  • Exercise or play
  • Environmental stimulants (e.g., cigarette smoke, strong odors, pollutants)
  • Emotional factors (e.g., laughing, crying, fear)
  • Drug intake (aspirin, nonsteroidal anti-inflammatory drugs, β-blockers)
  • Food additives
  • Endocrine factors (e.g., menses, pregnancy, thyroid dysfunction)
• Review of systems:
  • Symptoms of complicating factors (gastroesophageal reflux, sinusitis, allergies)
  • Dyspepsia, sour taste (gastroesophageal reflux); throat clearing, purulent nasal discharge, halitosis, cephalalgia, or facial pain (sinusitis); nasal itching, (“allergic salute”), eye rubbing, sneezing, watery nasal discharge (allergies)
• Impact of asthma:
  • Number of hospitalizations/intensive care unit admissions
  • Number of emergency room visits/doctor’s office visits
  • Asthma attack frequency
  • Number of missed school days/parent workdays
  • Limitation on activity
  • Number of courses of systemic steroids needed
• Environmental history:
  • Type of home
  • Location of home (urban, suburban, rural)
  • Heating system/air conditioning
  • Use of humidifier
  • Presence of molds, cockroaches, rodents
  • Fireplace
  • Carpeting
  • Stuffed animals
  • Pets
  • Exposure to cigarette smoke

Asthma - physical exam

• Pulmonary examination may be normal when asymptomatic.
• Assess work of breathing:
  • Level of distress
  • Intercostal/supraclavicular muscle retractions
• Chest shape (i.e., normal versus barrel-shaped)
• Lung auscultation:
  • Wheezing
  • End-expiratory involuntary cough
  • Prolonged expiratory phase
  • Crackles or coarse breath sounds
  • Stridor (indicates extrathoracic airway obstruction)
• Head, eyes, ears, nose, and throat examination. Signs of allergies or sinusitis:
  • Watery or itchy eyes
  • Allergic shiners
  • Dennie lines
  • Nasal congestion
  • Boggy nasal turbinates
  • Nasal polyps
  • Postnasal drip
• General examination (vital signs):
  • Blood pressure (pulsus paradoxus)
  • Respiratory rate (tachypnea)
• Skin: Evidence of eczema
• Extremities: Digital clubbing (very rare in asthma; suggests alternative diagnosis)
• Physical examination trick: Forced-exhalation maneuver to observe for wheezes or for precipitating coughing

Asthma - tests

Asthma - lab

• Pulmonary function tests:
  • Essential for the assessment and ongoing care of children with asthma
  • Spirometry measures the degree of airway obstruction and the response to bronchodilators.
  • Values obtained can measure absolute degree of airway obstruction.
  • Serial values can follow progress of disease and response to treatment.
  • Children as young as 4–5 years old can usually perform spirometry with practice.
• Provocational testing:
  • Exercise challenge: Determines effect of exercise on triggering airway obstruction
  • Cold-air challenge: Indirect test of airway hyperresponsiveness
  • Methacholine challenge: A positive test supports the diagnosis of asthma (useful in cases for which history is equivocal and pulmonary function test is normal), measures the degree of airway hyperreactivity
• Allergy evaluation:
  • Blood tests (eosinophil count, IgE level)
  • Skin testing (best test for assessing allergen sensitivity)
  • RAST testing (not as accurate as skin testing)
  • Sputum/nasal examination for presence of eosinophilia
• Other studies:
  • Gastroesophageal reflux evaluation
  • pH probe
  • Milk scan
  • Barium swallow (confirms normal anatomy)
• Peak flow meter (home testing):
  • Measures peak flow rate (PEFR)
  • Effort dependent
  • Assesses central, not peripheral airway obstruction
  • Used with patients who have poor symptom recognition or labile asthma
  • Dips in peak flow rate precede onset of clinical asthmatic symptoms.
  • Peak flow rate should be performed at least once a day.
  • Peak flow rate values are divided into 3 zones:
    • Green: ≥80% of baseline
    • Yellow: 50–80% of baseline
    • Red: 50% of baseline
  • Specific peak flow rate guidelines should be individualized for each patient based on the best measurement obtained during a 14-day period when the child is well.

Asthma - imaging

• Chest x-ray should be obtained if the diagnosis is uncertain or there is not the expected response to treatment, to rule out congenital lung malformations or obvious vascular malformations.
  • Findings can be normal.
  • Common findings are peribronchial thickening, subsegmental atelectasis, and hyperinflation.
• Sinus CT is useful if symptoms suggest sinusitis.
• Chest CT should be performed if bronchiectasis or anatomic abnormality is suspected.

Asthma - diag proced-surgery

Bronchoscopy can rule out:

• Anatomic malformations
• Foreign bodies
• Mucus plugging
• Vocal cord dysfunction
• Assess for aspiration (lipid-laden macrophages)

Asthma - differencial diagnosis

• Infectious:
  • Pneumonia
  • Bronchiolitis
  • Chlamydia infection
  • Laryngotracheobronchitis
  • Sinusitis
  • Immune deficiency
• Mechanical:
  • Extrinsic airway compression
  • Vascular ring
  • Foreign body
  • Vocal cord dysfunction
  • Tracheobronchomalacia
• Miscellaneous:
  • Cystic fibrosis
  • Bronchopulmonary dysplasia
  • Pulmonary edema
  • Gastroesophageal reflux
  • Recurrent aspiration
  • Bronchiolitis obliterans

Asthma - TREATMENT

Asthma - general measures

Asthma - diet

• Avoid foods or food additives (if truly allergic).
• Food-induced asthma is uncommon.

Asthma - special therapy

Asthma - comp alt-medicine

• Miscellaneous drugs used in severe cases
• Steroid-sparing agents:
  • Troleandomycin (TAO): Macrolide antibiotic; decreases clearance of corticosteroids, thus prolonging the effects of corticosteroids on the lung; lower corticosteroid dosing required
  • Methotrexate: Potent immunosuppressive drug; needs further investigation in children
  • Cyclosporine: Shown to have steroid-sparing effect in adult population with asthma; side effects are significant and may limit use
  • Magnesium sulfate (MgSO
  • Helium:
    • May improve airflow in severe asthma
    • Can improve ventilation and potentially oxygenation
  • Immunotherapy:
    • Efficacy in asthma is controversial
    • Most effective if a single antigen can be identified
    • Used only in select cases if medical management and environmental control measures are ineffective

  Asthma - medication

  • Corticosteroids (anti-inflammatory agents):
    • Most effective anti-inflammatory agents
    • Inhaled: Reduce airway inflammation and hyperresponsiveness more than any other inhaled agents; inhibit production and release of cytokines and arachidonic acid–associated metabolites; enhance β-adrenoceptor responsiveness; side effects include oral thrush; may minimally affect growth velocity at moderate or high doses
    • Dosage individualized to each patient. Agents vary in topical potency and systemic bioavailability; available as pMDIs, dry-powder inhalers (DPIs), or nebulized. Fluticasone (Flovent) 44, 110, 220 mcg/puff pMDI; budesonide (Pulmicort) 200 mcg/puff DPI; 250- and 500-mcg vials for nebulizer; beclomethasone (Beclovent, Vanceril, Qvar) 40, 42, 80, 84 mcg/puff; triamcinolone (Azmacort) 100 mcg/puff; flunisolide (Aerobid) 250 mcg/puff
    • Oral: Used for asthma exacerbations or for severe asthma that cannot be otherwise controlled. Exacerbations: Prednisone 1–2 mg/kg/d for 3–7 days or longer; usually tapered if >7 days of therapy required or if systemic steroids are used frequently. Ongoing therapy: 0.5–1 mg/kg/d daily or every other day for patients with severe asthma. Undesirable side-effect profile. When used daily, assess bone density and for cataract formation at least yearly.
    • IV: Methylprednisolone (Solumedrol) 1–2 mg/kg IV q6–12h until improved and able to take oral medication
  • Leukotriene modifiers (anti-inflammatory agents):
    • Block the synthesis and/or action of leukotrienes
    • 5-Lipoxygenase inhibitors, zileuton: May cause hepatic dysfunction
    • Leukotriene receptor antagonists: Aafirlukast (10 mg; Accolate) and montelukast (4, 5, and 10 mg; Singulair)
    • Indicated as monotherapy for mild or exercise-induced asthma and in combination with an inhaled corticosteroid for more effective symptom control or using a lower dose of inhaled corticosteroid
  • Mast-cell stabilizers
    • Weak anti-inflammatory agents
    • Preparations: Cromolyn sodium (Intal); nedocromil sodium (Tilade)
    • Decrease bronchial hyperresponsiveness
    • Can be used prior to exercise for exercise-induced symptoms
    • No significant side effects
    • Inhaled: Nebulizer; MDI
  • βTheophylline (bronchodilator): 2nd-line agent used when more conventional therapies are unsuccessful; indications are chronic, poorly controlled asthma, and nocturnal asthma (if no gastroesophageal reflux); adjunctive therapy with β
  • Anticholinergic agents (bronchodilators): Adjunctive bronchodilators, may be useful in patients who only partially respond to β-agonists; preparations include Ipratropium bromide MDI or ampule for nebulization (Atrovent)
  • Monoclonal antibodies against IgE (Xolair) can be given as a monthly SC injection in severe asthma patients with moderately high IgE levels.

  Asthma - FOLLOW UP

  Long-term follow-up is essential to maintain normal activity and pulmonary function. All patients should use a valved holding chamber with pMDIs, and technique for all inhaled medications should be reviewed regularly.

  Asthma - disposition

  Asthma - issues for referral

  • A patient who requires hospitalization more than once a year, or who has required intensive care
  • A patient who requires frequent bursts of systemic corticosteroids
  • A patient whose airway obstruction is not easily reversible
  • A patient who has clinical features suggesting another pulmonary process

  Asthma - prognosis

  With proper therapy and good adherence to treatment regimen: Excellent

  Asthma - complications

  Morbidity:

  • Frequent hospitalizations and absence from school
  • Psychologic impact of having a chronic illness
  • Decline in lung function over time

  Asthma - patient monitoring

  Signs that may indicate problems:

  • Increased symptoms (cough day or night, wheeze)
  • Exercise limitations or symptoms during exercise
  • Decrease in peak flow rate
  • Increasing use of inhaled bronchodilators
  • Subject not improving on enhanced home therapy

  Asthma - bibliography

  1. Crater SE, Platts-Mills TA. Searching for the cause of the increase in asthma. Curr Opin Pediatr. 1998;10(6):594–599.
  Hakonarson H, Grunstein MM. Management of childhood asthma. In: Barnes P, Grunstein MM, Leff A, et al., eds. Asthma. Vol. 2. New York: Raven Press; 1997:1847–1868.
  2. Kercsmar CM. Current trends in management of pediatric asthma. Respir Care. 2003;48:194–205.
  3. Liu AH, Szefler SJ. Advances in childhood asthma: Hygiene hypothesis, natural history, and management. J Allergy Clin Immunol. 2003;111:S785–S792.
  National Asthma Education and Prevention Program. Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. NIH-NHLBI publication. Washington, DC: U.S. Government Printing Office; August 2007.
  4. Reid MJ. Complicating features of asthma. Pediatr Clin North Am. 1992;39:1327–1341.
  5. Salvatoni A, Piantanida E, Nosetti L, et al. Inhaled corticosteroids in childhood asthma: Long-term effects on growth and adrenocortical function. Paediatr Drugs. 2003;5:351–361.
  6. Silverstein MD, Mair JE, Katusic SK, et al. School attendance and school performance: A population-based study of children with asthma. J Pediatr. 2001;139(2):278–283.
  7. Stempel DA. The pharmacologic management of childhood asthma. Pediatr Clin North Am. 2003;50:609–629.
  8. Turktas I, Ozkaya O, Bostanci I, et al. Safety of inhaled corticosteroid therapy in young children with asthma. Ann Allergy Asthma Immunol. 2001;86(6):649–654.

  Asthma - ADDITIONAL READING

  Allen JL, Bryant-Stephens T, Pawlowski NA. The Children’s Hospital of Philadelphia Guide to Asthma. Philadelphia: Wiley-Liss; 2004.

  Asthma - CODES

  Asthma - icd9

  493.00 Childhood asthma

  493.01 Childhood asthma with status asthmaticus

  493.02 Childhood asthma with acute exacerbation

  Asthma - PATIENT TEACHING-MED

  Asthma - activity

  • Most patients with asthma can participate fully in sports, even at a high level, with close follow-up. Extra medications such as albuterol and/or cromolyn may be required before vigorous exercise. All athletes should have their quick-relief medications on hand at all times.
  • Athletes with asthma may need to report their medications to the governing bodies of their sport.

  Asthma - prevent

  • Patient and caregiver education is mandatory to establish provider/caregiver partnership and ensure adherence with treatment plan.
  • Every patient/caregiver should be taught that asthma is a chronic, inflammatory condition that can be controlled with proper therapy.
  • All medications should be explained and potential risks (side effects) and benefits reviewed.
  • A written asthma management plan should be provided, outlining daily therapy and an “action plan” for managing exacerbations of asthma.
  • Environmental counseling:
    • Avoid airborne irritants (tobacco smoke, wood stoves, noxious fumes).
    • Minimize dust-mite exposure.
    • Minimize stuffed animals, quilts, books, and clutter.
    • Use dust mite–proof coverings on mattresses, pillows, and box springs.
    • Wash pillows, blankets, and sheets in hot water.
    • Avoid molds by decreasing relative humidity to 50%.
    • Remove pets from child’s bedroom, and from house if patient is allergic to the animal.

  Asthma - FAQ

  • Q: Will my child outgrow his or her asthma?
  • A: Family history and allergies affect the ultimate outcome. Wheezing during the 1st 3 years of life is extremely common, with 40–50% of all children wheezing at some time. Many of these children do not develop asthma and “outgrow” their illness by school age. Some patients develop asthma again as young adults.
  • Q: Can my child become dependent on asthma medications?
  • A: Children do not become “dependent” on these medications as they would with narcotic agents. Daily asthma medications are required to maintain airway patency and to control airway inflammation.
  • Q: Will my child be on medications for the rest of his or her life?
  • A: This depends on the severity of the asthma. The types, doses, and frequency of asthma medications will change over a patient’s lifetime.
  • Q: Do inhaled steroids affect patient growth?
  • A: There is some transient and slight decrease in growth velocity seen in children who receive moderate-dose inhaled corticosteroids (~0.5 mg/d). Ultimate height does not seem to be affected.

  Book Source Details

  • Book Title: The 5-Minute Pediatric Consult
  • Author(s): M. William Schwartz MD; et al.
  • Year of Publication: 2008
  • Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
  
  

  More About Asthma

  • Back to disease: Asthma: Introduction
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  • More Book Extracts: All Online Books for Asthma

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  Review other book chapters online related to Asthma:

  Medical Books Excerpts
  • STRIDOR
  • "Algorithmic Diagnosis of Symptoms and Signs" (2003)
  • [ read ]
  • WHEEZING
  • "Algorithmic Diagnosis of Symptoms and Signs" (2003)
  • [ read ]
  • Stridor & Wheezing
  • "In a Page: Signs and Symptoms" (2004)
  • [ read ]
  • Stridor
  • "In A Page: Pediatric Signs and Symptoms" (2007)
  • [ read ]
  • Wheezing
  • "In A Page: Pediatric Signs and Symptoms" (2007)
  • [ read ]
  • STRIDOR AND SNORING
  • "Differential Diagnosis in Primary Care" (2007)
  • [ read ]
  • Stridor
  • "Handbook of Signs & Symptoms (Third Edition)" (2006)
  • [ read ]
  • Wheezing [Sibilant rhonchi]
  • "Handbook of Signs & Symptoms (Third Edition)" (2006)
  • [ read ]
  • Wheezing
  • "A Pocket Manual of Differential Diagnosis" (1999)
  • [ read ]
  • Asthma
  • "Professional Guide to Diseases (Eighth Edition)" (2005)
  • [ read ]
  • Stridor
  • "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
  • [ read ]
  • Wheezing [Sibilant rhonchi]
  • "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
  • [ read ]
  • Stridor
  • "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
  • [ read ]
  • Wheezing
  • "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
  • [ read ]
  • Wheezing
  • "Field Guide to Bedside Diagnosis" (2007)
  • [ read ]
  • Asthma
  • "Handbook of Diseases" (2003)
  • [ read ]
  • Stridor
  • "Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series" (2007)
  • [ read ]
  • Wheezing
  • "Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series" (2007)
  • [ read ]
  • Stridor
  • "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
  • [ read ]
  • Wheezing
  • "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
  • [ read ]
  • Wheezing
  • "The Diagnostic Approach to Symptoms and Signs in Pediatrics" (2006)
  • [ read ]
  • Stertor, Stridor, and Airway Obstruction
  • "The Diagnostic Approach to Symptoms and Signs in Pediatrics" (2006)
  • [ read ]
  • Stridor
  • "Nursing: Interpreting Signs and Symptoms" (2007)
  • [ read ]
  • Wheezing [Sibilant rhonchi]
  • "Nursing: Interpreting Signs and Symptoms" (2007)
  • [ read ]
  • STRIDOR AND SNORING
  • "Differential Diagnosis in Primary Care" (2007)
  • [ read ]
  • Assure adequate oxygenation for asthmatic patients receiving albuterol
  • "Avoiding Common Pediatric Errors" (2008)
  • [ read ]
  • Assure that patients with severe asthma and status asthmaticus receive adequate intravascularvolume expansion
  • "Avoiding Common Pediatric Errors" (2008)
  • [ read ]
  • Asthma
  • "The 5-Minute Pediatric Consult" (2008)
  • [ read ]
   

  Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

  
  

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  More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

  
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