Asthma

Asthma Control Test

Score 5-25. Higher score = better control.

Symptoms/ Diagnosis

  • Variable wheeze, cough, chest tightness, dyspnea
  • Triggers: dust, pollen, smoke, wildfires, exercise, viral illness
  • Ask about childhood asthma, family history, premature birth
  • Spirometry with bronchodilator reversibility is standard
  • FEV1 ↑ ≥12% and ≥200 mL supports asthma
  • If spirometry normal → methacholine challenge
  • PEF can assist if spirometry unavailable

PFT's

Test Findings in Asthma Notes
FEV1/FVC Ratio ↓ Reduced (<0.75–0.80) Hallmark of obstructive lung disease
FEV1 Post-Bronchodilator ↑ ≥12% and ≥200 mL Confirms reversible airway obstruction
FEF 25–75% ↓ Reduced Suggests early small airway involvement
TLC Normal or ↑ Hyperinflation may occur in severe cases
RV ↑ Increased Air trapping due to airway obstruction
DLCO Normal Differentiates from COPD, which may have reduced DLCO
Methacholine Challenge FEV1 ↓ ≥20% at low doses Indicates airway hyperreactivity when spirometry is normal

Control

Asthma control is assessed using the Asthma Control Test (ACT)

  • ACT ≥20 = well controlled
  • ACT ≤19 = not well controlled

Treatment: Formoterol + ICS (Symbicort)

  • Mild: PRN Symbicort. 2 puffs prior to trigger
  • More symptoms: Symbicort BID with additional doses PRN for symptom relief
    • Formoterol preferred over salmeterol due to rapid onset (5-10 min vs 2 hours)
  • If no ICS-formoterol: use ICS whenever SABA used
  • Montelukast for allergic/exercise/ASA-sensitive asthma
  • Always check inhaler technique

Treatment Options

Qualifying criteria Step 1 Intermittent / very mild Step 2 Mild persistent Step 3 Moderate symptoms Step 4 More severe / frequent symptoms
Who fits this step
  • Symptoms ≤2 days/week
  • Night symptoms ≤2/month
  • Normal FEV1
  • Exacerbations ≤1/year
  • Symptoms 3 to 6 days/week
  • Night symptoms 2 to 4/month
  • Minimal activity limitation
  • ≥2 steroid-requiring exacerbations/year
  • Daily symptoms
  • Night symptoms >1/week
  • Some activity limitation
  • Airflow obstruction between flares
  • Frequent activity limitation
  • Night awakenings
  • More severe obstruction
Option 1 ICS-formoterol regimen Low-dose ICS-formoterol as needed Low-dose ICS-formoterol as needed Low-dose ICS-formoterol maintenance + reliever Medium-dose ICS-formoterol maintenance + reliever
Option 2 Alternative maintenance No daily controller Anti-inflammatory reliever only
or
Low-dose ICS daily 		Low-dose ICS-LABA
or
Low-dose ICS + LAMA or LTRA 		Medium-dose ICS-LABA
or
Medium-dose ICS + LAMA or LTRA
and and and and and
Alternative reliever ICS-SABA as needed
or
ICS + SABA as needed
or
SABA as needed 		ICS-SABA as needed
or
ICS + SABA as needed
or
SABA as needed 		ICS-SABA as needed
or
ICS + SABA as needed
or
SABA as needed 		ICS-SABA as needed
or
ICS + SABA as needed
or
SABA as needed

Inpatient Management

  • Assess severity: WOB, speech, accessory use, AMS, O2 need; red flags = silent chest, fatigue, rising CO2
  • O2 to SpO2 >92%
  • Bronchodilators: albuterol ± ipratropium (q2–4h or continuous if severe)
  • Steroids early: IV or PO, do not delay
  • Mg sulfate IV if severe or poor response
  • Reassess frequently: WOB, air movement, SpO2
  • VBG/ABG if worsening or c/f hypercapnia
  • CXR only if atypical or c/f PNA/PTX
  • Escalate: continuous nebs, consider NIV briefly, early ICU
  • Intubate if AMS, exhaustion, rising CO2, refractory hypoxemia
  • Avoid: sedatives, routine abx, stopping controller therapy
  • Discharge: stable on spaced nebs, off O2, steroids completed/prescribed, on ICS regimen, inhaler teaching + follow-up
Assess asthma exacerbation severity
↓
Signs of impending respiratory failure?
No
↓
Severe exacerbation?
PEF ≤50% predicted or personal best
Yes
↓
Admit, ICU/Anesthesia consult • SABA + ipratropium neb • O2 target SpO2 93 to 95% • IV methylprednisolone 40 to 60 mg • IV magnesium sulfate 2 g over 20 min • Assess alternate dx/comorbidities
Severe exacerbation
↓
• Nebulized SABA or SABA/ipratropium q20 min x1 hr or continuous • O2 target SpO2 93 to 95% • IV methylprednisolone 40 to 60 mg • Or prednisone 60 mg PO
Mild to moderate exacerbation
↓
• SABA by neb or MDI q20 min x1 hr, then PRN • O2 target SpO2 >92% • Prednisone 40 mg PO
Worsening
symptoms, PEF, SpO2
↓
Admit, ICU/Anesthesia consult • SABA/ipratropium nebs • O2 target SpO2 93 to 95% • IV methylprednisolone 40 to 60 mg if not already given • Assess alternate dx/comorbidities
Good response
Symptoms resolved, PEF >80%
↓
Discharge home • Reliever q4 to 6h PRN • Prednisone 40 to 60 mg/day x 5 days • Inhaler teaching + action plan • PCP follow-up • Resume/initiate ICS if needed
Incomplete response
Persistent dyspnea/wheeze or PEF 60 to 80%
↓
Continue observed treatment for another 1 to 3 hours and reassess
Good response
Symptoms resolved, PEF >80%
↓
Discharge home • Reliever q4 to 6h PRN • Prednisone 40 to 60 mg/day x 5 days • Inhaler teaching + action plan • PCP follow-up • Resume/initiate ICS if needed
Incomplete response after reassessment
Persistent symptoms/wheeze or PEF 60 to 80%
↓
Worsening
symptoms, PEF, SpO2
↓
Admit, ICU/Anesthesia consult • SABA/ipratropium nebs • O2 target SpO2 93 to 95% • IV methylprednisolone 40 to 60 mg if not already given • Assess alternate dx/comorbidities
Still incomplete
PEF 60 to 80%, prior severe exacerbations, or poor adherence
↓
Admit to hospital Continued treatment and monitoring
Substantial improvement
PEF 60 to 80%, good understanding/follow-up
↓
Discharge home • Reliever q4 to 6h PRN • Prednisone 40 to 60 mg/day x 5 days • Inhaler teaching + action plan • PCP follow-up • Resume/initiate ICS if needed

Outpatient Exacerbations

  • Use personal best PEF
    • Green ≥80% → continue usual meds
    • Yellow 50–79% → step up meds, monitor closely
    • Red <50% → send to ED
  • Send to ED regardless of PEF if patient has: severe dyspnea, speaking only short phrases, accessory muscle use, no improvement after rescue therapy

Asthma Phenotypes

  • High T2 Inflammation: Allergic asthma, high eosinophils, responds to ICS and biologics
  • Low T2 Asthma: Poor response to biologics, limited treatment options
  • Cough-variant Asthma: Montelukast may help
  • Obesity-associated Asthma: Unique pathophysiology, often harder to control

References

  1. Global Initiative for Asthma. (2025). Global strategy for asthma management and prevention: 2025 update. https://ginasthma.org/reports/
  2. Cloutier, M. M., Baptist, A. P., Blake, K. V., Brooks, E. G., Bryant-Stephens, T., DiMango, E., Dixon, A. E., Elward, K. S., Hartert, T., Krishnan, J. A., Lemanske, R. F., Ouellette, D. R., Pace, W. D., Schatz, M., Skolnik, N. S., Stout, J. W., Teach, S. J., Umscheid, C. A., Walsh, C. G., & O'Connor, G. T. (2020). 2020 focused updates to the asthma management guidelines: A report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. The Journal of Allergy and Clinical Immunology, 146(6), 1217–1270. https://doi.org/10.1016/j.jaci.2020.10.003
  3. National Asthma Education and Prevention Program. (2007). Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/guidelines-for-diagnosis-management-of-asthma
  4. British Thoracic Society, National Institute for Health and Care Excellence, & Scottish Intercollegiate Guidelines Network. (2024). Asthma: Diagnosis, monitoring and chronic asthma management. NICE guideline NG245. https://www.nice.org.uk/guidance/ng245
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