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Asthmatic excerbation full details for md exams

Acute Asthma Exacerbation (for MD exam prep)

1) Definition

An asthma exacerbation is an acute or subacute worsening of symptoms and lung function from baseline, caused by increased airway inflammation and bronchoconstriction.

2) Common Triggers

  • Viral URTI (most common)
  • Allergen exposure (dust mites, pollen, pets, molds)
  • Air pollution, smoke, occupational irritants
  • Exercise, cold air
  • Nonadherence to controller therapy
  • Drugs: NSAIDs (aspirin-exacerbated respiratory disease), beta-blockers
  • GERD, rhinosinusitis, stress

3) Pathophysiology (exam wording)

  • Airway inflammation -> mucosal edema
  • Bronchial smooth muscle constriction -> airflow limitation
  • Mucus hypersecretion and plugging
  • Dynamic hyperinflation, V/Q mismatch, increased work of breathing
  • Severe attack can progress to respiratory muscle fatigue, hypercapnia, respiratory failure

4) Clinical Features

Symptoms

  • Breathlessness, chest tightness, wheeze, cough (often nocturnal)

Signs

  • Tachypnea, tachycardia
  • Prolonged expiratory phase, diffuse wheeze
  • Accessory muscle use, inability to complete sentences
  • Severe/life-threatening: silent chest, cyanosis, altered sensorium, exhaustion, hypotension/bradycardia (preterminal)

5) Severity Classification (adult, practical exam style)

Use symptoms + vitals + PEF/FEV1 + oxygenation.

Mild to Moderate

  • Talks in phrases, prefers sitting
  • RR increased but no severe distress
  • HR < 120/min
  • SpO2 >= 94%
  • PEF > 50% predicted/best

Severe

  • Talks in words only, agitated, marked accessory muscle use
  • RR >= 30/min
  • HR >= 120/min
  • SpO2 < 90-92%
  • PEF <= 50% predicted/best

Life-threatening / Near-fatal

  • Silent chest, poor respiratory effort
  • Drowsy/confused/coma
  • Cyanosis, hypotension, arrhythmia
  • PEF < 33%
  • ABG: normal/rising PaCO2 (ominous), severe hypoxemia
  • Near-fatal: raised PaCO2 requiring ventilatory support

6) Evaluation in Emergency

  • Rapid ABC assessment
  • Pulse oximetry continuously
  • PEF (or FEV1 if feasible) before and after treatment
  • ABG if severe, SpO2 low, exhaustion, or poor response
  • CXR only if suspicion of pneumothorax, pneumonia, edema, or poor response
  • Labs not routine (electrolytes if repeated beta-agonists, severe illness)
  • ECG if severe tachycardia/chest pain/comorbidity

7) Acute Management (core exam answer)

First hour bundle

  1. Oxygen
    • Target SpO2 93-95% (nonpregnant adults)
  2. Inhaled SABA (salbutamol/albuterol)
    • MDI + spacer (4-10 puffs q20 min x 1 hour) or nebulized 2.5-5 mg q20 min in severe attack
  3. Add inhaled ipratropium in severe exacerbation
    • Neb 0.5 mg q20 min for first hour
  4. Systemic corticosteroid early (within 1 hour)
    • Prednisolone 40-50 mg PO daily, usually 5-7 days
    • If unable PO: hydrocortisone IV / methylprednisolone IV

If poor response / severe attack

  1. IV magnesium sulfate
    • 2 g IV over ~20 min (adults)
  2. Consider continuous nebulized SABA
  3. Senior/ICU review early

Not routinely recommended

  • Routine antibiotics (unless clear bacterial infection)
  • Sedatives/anxiolytics
  • Mucolytics/chest physiotherapy in acute attack

8) Indications for ICU / intubation

  • Deterioration despite maximal therapy
  • Exhaustion, altered mental status
  • Silent chest, severe hypoxemia
  • Rising or persistently elevated PaCO2 with acidosis
  • Hemodynamic instability, arrhythmias
  • Respiratory arrest/imminent arrest

Ventilation pearls (viva points)

  • Intubation is high risk in asthma
  • Use low RR, prolonged expiratory time, low tidal volume strategy
  • Accept permissive hypercapnia to avoid dynamic hyperinflation/barotrauma
  • Watch for hypotension and pneumothorax

9) Disposition (admit vs discharge)

Admit if:

  • Persistent symptoms after initial treatment
  • PEF/FEV1 < 60% predicted/best after therapy
  • Prior ICU/intubation history, frequent recent exacerbations
  • Significant comorbidity, poor social support, pregnancy concerns

Discharge possible if:

  • Symptoms minimal, no significant distress
  • PEF > 60-80% and sustained response
  • SpO2 stable on room air
  • Clear home plan and follow-up arranged

10) Discharge Plan (very important in exams)

  • Start/step up ICS-containing controller (preferably ICS-formoterol based regimen where appropriate)
  • Reliever plan clearly written
  • Oral steroid completion instructions if prescribed
  • Inhaler technique check and adherence counseling
  • Trigger/risk factor management (smoking cessation, allergen control)
  • Written asthma action plan
  • Follow-up in 2-7 days (or earlier if high risk)

11) Risk factors for asthma-related death (high-yield)

  • Previous near-fatal attack/intubation
  • Hospital/ED visit in last year
  • Overuse of SABA, underuse/no ICS
  • Recent or ongoing systemic steroid use
  • Psychiatric illness, substance use
  • Poor adherence, poor perception of severity
  • Food allergy with asthma

12) Short “exam format” management summary

“Assess ABC, oxygen to target saturation, repeated inhaled SABA, add ipratropium for severe attack, give systemic corticosteroid early, reassess with PEF/SpO2/clinical signs, give IV magnesium if poor response, escalate to ICU if impending respiratory failure, and ensure ICS-based long-term control with written discharge action plan.”
If you want, I can also give:
  1. Pediatric acute asthma protocol,
  2. One-page flowchart for ward/emergency,
  3. OSCE viva questions + model answers.
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