asthma%20(pediatric)
ASTHMA (PEDIATRIC)

Asthma is a chronic inflammatory disease of the airways in the lungs of children and adults.
The patient usually complains of shortness of breath, chest tightness and coughing with wheezing.

A diagnosis of asthma in young children is more likely if they have symptom patterns, presence of risk factors for development of asthma and therapeutic response to controller treatment.
Goals of treatment are effective symptom control with minimal or no exacerbations, minimal or no nocturnal and daytime symptoms, no limitations on activities, minimal or no need for reliever treatment, and minimal adverse effects of medication.

Asthma%20(pediatric) Diagnosis

Diagnosis

  • A diagnosis of asthma in children is more likely if they have:
    • Symptom patterns [wheeze, cough, breathlessness (typically manifested by activity limitation), and nocturnal symptoms or awakenings]
    • Presence of risk factors for development of asthma
    • Therapeutic response to controller treatment
    • Episodic symptoms of airflow obstruction or airway hyperresponsiveness
    • Airflow obstruction is at least partially reversible
    • Alternative diagnoses are excluded

History

  • Identify the symptoms likely to be due to asthma
  • Support the likelihood of asthma (eg patterns of symptoms, family history of asthma and atopic disease)
  • Determine symptom pattern for the past 3-4 months
    • Focus on symptoms that occurred in the past 2 weeks
  • History of variability is essential in the diagnosis of asthma
    • Variability refers to improvement or worsening of symptoms and lung function occurring over a period of time (eg day to day, month to month or seasonally)

Key Indicators for Considering a Diagnosis of Asthma

  • Episodes of wheezing occurring more than once a month or symptoms occur >3 episodes/year
    • Wheezing occurring during sleep, activity, laughing, or crying, and with increasing recurrence is likely due to asthma
  • Activity-induced cough, usually accompanied by wheeze or heavy breathing
  • Nighttime cough or wheeze in the absence of viral infection
  • Heavy breathing, shortness of breath, or difficult breathing during exercise or activity, that is noticeably recurrent increases the likelihood of asthma
  • Persistence of asthma symptoms beyond age 3 year
  • Symptoms triggered or exacerbated by animal fur, aerosol, temperature changes, dust mites, drugs, etc
  • Symptoms (eg cough, wheeze, heavy breathing) lasting longer than 10 days in the presence of an upper respiratory tract infection (URTI)
  • Symptoms improve with asthma medication
  • Presence of patient history or family history of allergic disease (eg atopic dermatitis, allergic rhinitis)

Physical Examination

  • Perform a thorough exam with focus on observation of forced expiration and nasal inspection
  • Hyperexpansion of the thorax
  • Wheezing during normal breathing or prolonged forced exhalation
  • Increased nasal secretion, mucosal swelling or nasal polyps
  • Signs of allergic skin condition
  • Occasionally, wheezing may not be seen in severe asthma attacks due to markedly reduced airflow and ventilation
    • Other signs may be present (eg cyanosis, drowsiness, tachycardia, difficulty speaking)

Laboratory Tests

Pulmonary Function Testing

Spirometry

  • Preferred diagnostic method
    • Measures airflow limitation and determines reversibility
    • All measurements should be done before and after administration of inhaled short-acting bronchodilator
  • Generally valuable in children ≥5 years of age
    • Some children cannot correctly execute the required maneuvers until age 7 years
  • Forced vital capacity (FVC) is a measure of the maximal volume of air exhaled from the point of maximal inhalation
  • Volume of air exhaled during the 1st second of this maneuver is called forced expiratory volume in 1 second (FEV1)
    • FEV1 indicates risk for exacerbations
  • FEV1/FVC appears to be a more sensitive measure of severity of impairment
  • Increase in FEV1 ≥12% after administration of a bronchodilator indicates reversible airflow limitation

Peak Expiratory Flow (PEF) Measurements

  • Important in diagnosis and monitoring of asthma

Bronchodilator Response

  • Determines reversibility of airflow limitation in response to treatment

Fractional Concentration of Exhaled Nitric Oxide (FENO) Measurement

  • Associated with increases in eosinophilic levels
  • An increase in fractional concentration of exhaled nitric oxide (FENO) >4 weeks after an upper respiratory tract infection (URTI) in preschool children with recurrent symptoms may help in the diagnosis and in predicting intranasal corticosteroid use by school-age
  • Further studies are needed to prove the use of fractional concentration of exhaled nitric oxide (FENO) measurement as a guide for adjusting asthma treatment

Other Tests

  • There are several lung function tests that do not rely on patient’s cooperation or the ability to perform the required maneuvers
    • May be valuable in children 2-5 years of age
    • These are not evaluated as diagnostic tests for asthma
    • Commonly used in research studies and specialist centers
    • Eg impulse oscillometry, specific airway resistance, measurements of residual volume
  • Chest radiograph may be used to rule out other pathologies and structural abnormalities

Allergy Tests

  • Presence of food-specific immunoglobulin E (IgE) and/or atopic dermatitis increases the risk of sensitization to inhaled allergens and may be predictive of developing asthma

In vivo Test

  • Skin prick test

In vitro Test

  • IgE panel test/radioallergosorbent test (RAST)
    • May be done if in vivo test cannot be performed (eg cases of severe dermatitis)
    • May be performed if current antihistamine therapy cannot be discontinued, or if there is a known possibility of a life-threatening reaction to food or inhalant

Asthma Diagnosis in Children ≤5 Years

  • Objective measurements of lung function may be difficult in this age group
  • Atopy is a major risk factor for subsequent development of asthma in this age group and it also predicts severity once asthma develops
  • To help establish a diagnosis of asthma, a diagnostic trial of asthma medications, in addition to a thorough medical history and physical exam, may be useful
  • Consider asthma if >3 episodes of reversible bronchial obstruction have been noted within the last 6 month
    • Patients may have virus-induced asthma which is common in this age group

Assessment

ASSESS THE LEVEL OF CONTROL OF ASTHMA (FOR THE PAST 4 WEEKS)
Controlled
(All of the following)
Partly Controlled
(Presence of 1-2 of these)
Uncontrolled
(Presence of 3-4 of these)
Children ≤5 years old Adolescents and Children 6-11 years old Children ≤5 years old Adolescents and Children 6-11 years old
Frequency of daytime symptoms None >Few min, >once a week >2x/week >Few min, >once a week >2x/week
Limitation of activities None Any Any Any Any
Nocturnal waking up or coughing due to asthma None Any Any Any Any
Need for reliever medication* None >once/week >2x/week >once/week >2x/week
*Reliever medications taken prior to exercise excluded.
Note: Lung function is not a reliable test for children <5 years old.
Adapted from: Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention: Updated 2020.

Severity Assessment of Asthma Exacerbation

  • Asthma exacerbation is an acute or sub-acute deterioration in symptom control that is sufficient to cause distress or risk to health and would need specialist consult or requires treatment with systemic corticosteroid
    • Episode of progressive increase in wheeze and shortness of breath, cough especially when the child is asleep, lethargy or reduced exercise tolerance, impairment of daily activities (including feeding) and poor response to reliever medication
  • Severity must be assessed immediately through history, physical examination, and objective measures of lung function while initiating treatment with short-acting beta2-agonist and O2
    • Peak expiratory flow (PEF) or forced expiratory volume in 1 second (FEV1) and arterial oxygen saturation should be measured to determine the degree of hypoxemia
      • PEF or FEV1 are more reliable indicators of airflow limitation severity and may also help determine patients who require hospitalization (eg patients with pre-treatment FEV1 or PEF <25% predicted or personal best or patients with post-treatment FEV1 or PEF <40% predicted or personal best)
    • Evaluate patient’s severity for risk of death based on the following:
      • Past history of near-fatal asthma requiring intubation and mechanical intubation
      • Prior (within 1 year) hospitalization or emergency care visit due to asthma exacerbation
      • Currently using or recently stopped oral glucocorticosteroids
      • Currently not on inhaled glucocorticosteroids
      • Overdependent on rapid-acting inhaled beta2-agonists (eg use of >1 canister per month)
      • History of psychiatric disease or psychosocial problems
      • History of poor compliance with asthma medication or asthma action plan
      • Difficult to perceive airflow obstruction or severity
  • Severe asthma attack requires close supervision as it may be life threatening
    • Treatment should continue until PEF or FEV1 has returned to their previous ideal value or plateau
    • Asthma phenotyping is recommended for patients diagnosed with severe asthma
      • Patients with residual type 2 airway inflammation are likely to respond to add-on biologic type 2-targeted therapy (eg Omalizumab, Mepolizumab, Benralizumab, Dupilumab)
  • Immediate medical attention is needed when:
    • There is a presence of acute distress in the child
    • Inhaled bronchodilator did not relieved promptly the child’s symptoms
    • Progressively shorter period of relief after doses of rapid acting beta2-agonist
    • There is a need for a child <1 year to have repeated inhaled rapid acting beta2-agonist administration over several hours
  • Immediate hospital transfer is indicated in children ≤5 years old with any of the following:
    • Inability to speak or drink
    • Cyanosis, subcostal retractions
    • SaO2 at <92% when without breathing support
    • Silent chest sounds upon ausculation
    •  No improvement seen after initial bronchodilator treatment: Unresponsive to 6 puffs of inhaled short-acting beta2-agonist within 1-2 hours or persistent tachypnea after 3 doses of inhaled short-acting beta2-agonist even if with clinical signs of improvement
    • Availability of acute treatment is affected by patient's environment or caretaker's ability to manage acute asthma at home

Initial Assessment of Acute Asthma Exacerbation

Mild-Moderate

  • No altered consciousness
  • Arterial O2 saturation (SaO2) at >90-95% (≥92% for children 5 years)
  • Talks in phrases/sentences
  • Pulse rate <100 beats/minute; ≤200 bpm (0-3 years)/≤180 bpm (4-5 years) pulse rate
  • No central cyanosis
  • Increased respiratory rate
  • Variable wheeze intensity

Severe

  • Agitated, confused, drowsy
  • SaO2 at <92%
  • Talks in words
  • Pulse rate >120 bpm (>5 years); >200 beats/minute (0-3 years) or >180 beats/minute (4-5 years)
  • Cyanosis may likely be present
  • Subcostal and/or subglottic retractions present
  • Hunched forward while sitting
  • Respiratory rate >30/minute
  • Wheeze may not be present

Life-threatening

  • Unable to speak 
  • Drowsy, confused or silent chest
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