asthma
ASTHMA
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.
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.

Monitoring

Good Response

  • Patient’s response is maintained x 60 minutes after last treatment
  • Normal physical exam
  • PEF >70%
  • Patient is free of distress
  • O2 saturation >90% (>95% in children)
Incomplete Response
  • History of high-risk patient
  • Mild-moderate symptoms on physical exam
  • PEF <60%
  • O2 saturation not improving
Poor Response
  • History of high-risk patient
  • Severe symptoms, drowsiness, confusion on physical exam
  • PEF <30%
  • PaCO2 >45 mmHg
  • PaO2 <60 mmHg
Consider Admission to ICU if:
  • Severe asthma & no response to initial therapy in the emergency dept or worsening asthma despite therapy
  • Signs of imminent resp arrest (eg confusion, drowsiness, loss of consciousness)
  • Hypoxemia despite supplemental O2 which is indicative of impending resp arrest:
    • PaO2 <60 mmHg (8 kPa) &/or PaCO2 >45 mmHg (6 kPa) or SaO2 by oximetry 90% in children

Intubation

  • Consider if there is continued deterioration despite optimal therapy
  • Exhausted patient &/or PaCO2 is increasing

Consider Home Discharge

  • PEF >60-80% predicted/personal best, SaO2 >94% room air & is sustained on oral/inhaled medication

Prevention

  • Avoiding or reducing risk factors is an effective way to prevent the development of asthma & decrease exacerbation

Prevention of Asthma

  • Preventing the development of atopy & asthma in infants & children may be started before & after birth
    • Avoid tobacco exposure
    • Breastfed infants have lower incidence of wheezing illnesses during early childhood
      • Infants who are exclusively breastfed on their 1st month have lower risk for childhood asthma
    • Broad-spectrum antibiotic use should be avoided during the 1st year of life 
    • There is insufficient data supporting the need for prescribing antigen-avoidance diet to high-risk pregnant mothers & for the role of probiotics
Prevention of Asthma Symptoms & Exacerbation
  • Treating modifiable risk factors & comorbidities is the key to asthma exacerbation prevention
  • Asthma exacerbation is usually triggered by various factors (eg allergens, viral infections, pollutants, drugs)
    • Decreasing patient’s trigger exposure improves asthma control & reduces medication use

Indoor Allergens

  • Domestic mites
    • Encasing mattresses, washing linens with hot water, removing dusts & reducing habitats of mites may help decrease exposure
  • Furred animals
    • There are conflicting evidences on the effect of pet allergens on patients with asthma 
    • Elimination from home is encouraged, however, allergen levels are only decreased many months after complete removal of the animal
  • Cockroaches
    • Eliminate suitable environment, limit their access, control by use of chemical or trapping
  • Fungi
    • Dampness, visible mold and mold odor should be eliminated as studies suggested that exposure to these home allergens increase the risk of developing asthma

Outdoor Allergens

  • Reduce exposure by closing the doors or windows, staying indoors when pollens & mold counts are high, & by using air conditioners

Outdoor Air Pollutants

  • Increased level of air pollution is associated with asthma exacerbation
  • Thunderstorms, temperature & humidity changes occasionally increases asthma symptoms
  • Patients with uncontrolled asthma should not be engaged in any strenuous physical activity in cold weather, low humidity, or high air pollution
    • They should refrain from any smoke-filled area
    • They should stay in a climate-controlled place

Occupational Exposure

  • Responsible for considerable number of asthma cases in adults
  • Early recognition of work sensitizers & avoidance of exposure are important

Food & Food Additives

  • Common primarily in children
  • When food allergy is confirmed, it should be avoided
  • Sulfite, a common preservative found in processed potatoes, shrimp, wine, beer, dried fruits, etc, is usually implicated in asthma exacerbation

Drugs

  • Aspirin & NSAIDs have been implicated in asthma exacerbation
  • Beta-blockers may aggravate bronchospasm
  • Excessive use of short-acting beta2-agonists (>1 200-dose canister/month) may exacerbate flare-ups

Influenza Vaccination

  • Yearly vaccination is recommended in patients with moderate to severe asthma

Obesity

  • Increased body mass index (BMI) is associated with asthma, but reason behind is still unknown
  • Weight reduction improves lung function, symptoms, disease occurrence & health status of obese asthmatics

Physical Activity

  • Light to moderate tolerable exercise should be encouraged especially for patients with comorbidities caused by weight problems
    • Sufficient warm-up before training may increase tolerance for exercise
  • Lack of exercise in children may lead to poor metabolism & may lead to obesity
  • Patients with exercise-induced asthma should be advised accordingly
    • A reliever medication prior to exercise may be prescribed

Others

  • Extreme emotional expression & panic attacks may cause hyperventilation & hypocapnia, which leads to airway narrowing
  • History of intubation or confinement to ICU for asthma increases the risk for exacerbations
  • Rhinitis, sinusitis, polyposis, & gastroesophageal reflux can exacerbate asthma

Follow Up

  • Previously hospitalized patients should return for follow-up within 2-7 days after discharge
  • Patient should be monitored 1-3 months after the 1st consultation, & then every 3 months thereafter
  • After an exacerbation, patient should be seen within 1 week to 1 month
  • Lung function should be assessed & recorded at least every 1-2 years
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