Internal Medicine Pulmonology

Asthma Exacerbation

Asthma

Background – Asthma

Acute asthma can be a life-threatening condition. Modern maintenance therapy, mainly with inhaled steroids, has reduced the number of people seeking care for acute asthma. Asthma can debut at any age. It appears that many patients seek emergency treatment due to asthma, without having been diagnosed with the disease before.


Causes

Asthma is a multifactorial disease and therefore the causes of the acute asthma exacerbation vary. Common causes are:

  • Poor compliance with prescriptions
  • Respiratory infection
  • Allergen exposure (eg Cat allergy)
  • Hypersensitivity to drugs (eg ASA hypersensitivity)
  • Physical effort
  • Cold air

Symptoms – Asthma

  • Respiratory distress. Present both in inspiration and expiration.
  • Rhonchi

Clinical findings in severe asthma

  • General appearance: Shortness of breath. Malaise. If the exacerbation is life-threatening, the patient may be numb or unconscious.
     
  • Lungs: Abundant rhonchi. Note that lack of breath sounds can be a sign of life-threatening asthma. Extended expirium.
     
  • Respiratory rate: >25 breaths/min. Measured as part of vital parameter B (breathing).
     
  • PEF: <40% of normal value (<200 L/min if normal value is not known).
     
  • Heart: Heart rate >120/min.
     
  • Oxygen saturation (in case of breath): <91%. Measure blood gases.

Differential Diagnoses – Asthma


Investigation and Lab Testing – Asthma

Besides auscultation of heart and lungs:

  • Spirometry (FEV1), (possibly PEF). NOTE! Not performed on a patient who is severely affected
  • Oxygen saturation (oxymetry or blood gas)

In severe attacks:

  • Insert line
  • Arterial blood gas
  • Electrolyte check
  • CBC
  • CRP
  • Chest X-ray if you suspect pneumonia or pneumothorax

Acute Asthma Treatment in Adults

(Pregnant women are given the same treatment)

  1. Oxygen:
    Via nasal cannula, 4-6 liters/min, to reach SaO2 ≥ 90%. (Note – in case of COPD suspicion give only 0.5 liters/min via nasal cannula until blood gas response is obtained)
     
  2. Inhalation of beta-2 agonists
    Primarily by an inhaler with a spacer (equivalent effect with a nebulizer) eg salbutamol (Ventoline Evohaler) 0.1 mg/dose. In severe attack – administered together with ipratropium (Atrovent inhalation spray 20 µg/dose)
     
  3. If inhalation is given via nebulizer:
    1-2 ml salbutamol (Ventoline) inhalation solution 5 mg/ml.
    The above inhalation is combined with 2 ml of ipratropium bromide (Atrovent) 0.25 mg/ml in a severe attack.
     
  4. If for some reason the patient is unable to inhale, beta-2 agonists are given parenterally:
    Terbutaline injection (Bricanyl) 0.5 mg/ml: 0.5-1.0 ml subcutaneously.
    In severe asthmatic episodes, 1 ml of the injection solution is diluted with 10 ml of NaCl and administered slowly (5 minutes) intravenously.
     
  5. Steroids: In moderate to severe attacks, steroids are given orally if the patient can cooperate.
    betamethasone 4-8 mg dissolved in water
    or
    prednisolone 30-60 mg
    If the patient is unable to cooperate (eg unconscious):
    8 mg betamethasone or 40 mg methylprednisolone iv
     
  6. Possible theophylline for more severe attacks:
    Administered slowly (30 minutes) iv. Never in central vein. First, check (if possible) S-theophylline. Overdose can cause life-threatening arrhythmias.

    If the patient is on maintenance therapy with theophylline:
    Give 2-3 mg/kg body weight of Theophylamine 23 mg/mL slowly iv (equivalent to about 0.15 mL/kg body weight).

    If the patient is not on maintenance therapy with theophylline:
    Give 5-6 mg/kg body weight of Theophylamine 23 mg/mL slowly iv (equivalent to about 0.30 mL/kg body weight).
    If continued treatment with theophylamine is given, S-theophylline must be checked continuously.

Continued care – Asthma

In case of insufficient effect of the emergency treatment:

  • Admit to inpatient care
     
  • Re-evaluate the diagnosis
     
  • Consider ICU care
     
  • Repeat inhalation of beta-2 agonist and ipratropium bromide
     
  • Continued steroid therapy is given orally, initially divided into two or more doses per day (first day 1.5-2 mg Prednisolone per kg body weight, after improvement the same cortisone regimen as mentioned below).
     
  • If the patient shows signs of poor ventilation despite treatment – consider life support devices (mechanical ventilation machine).

Indications for inpatient care

  • The patient did not respond adequately to the treatment
  • Repeated emergency department visits due to asthma
  • Labile asthma – often asthma attacks at night or morning
  • Lack of disease awareness (high-risk patient)

On returning home from the emergency visit

  • Follow-up cortisone:
    Prednisolone 30 mg/day for 5-10 days
    or
    Betapred 3 mg/day for 5-10 days
    (After this period of treatment, no tapering is required)
     
  • Assess risk factors
     
  • Explain the rationale behind use of medication
     
  • Check the inhalation technique
     
  • Prepare action plan in case of emergency
     
  • Follow-up physician visits:
    Primary care physician visit within 6 weeks.
     
  • Referral to specialist in:
    – Asthma worsening during pregnancy
    – Unclear triggering factor
    – Recurrent severe obstructive events
    – Labile asthma

Further Reading