Here I am dealing with the classification of the severity of asthma.
Clinically there is an enormous variation from patient to patient who has asthma.
In order to clarify what the various forms of asthma are, an Expert Panel reported in 1997 four classes of asthma (Ref. 2). Below is a modification of their summary in tabular form.
It is important to make a distinction between these various forms of severity of asthma as the treatment modalities will be adapted to how severe the asthma is. Severe asthma will likely need more corticosteroids in the combination of medications and the lung specialist (pulmonologist) will need to watch these patients more closely.
Asthma Classification by Severity
|I: mild intermittent||Symptoms less than 2 times per week, asymptomatic in between with normal **PEF; flare-ups last only hours or a few days; night asthma attacks less than 2 times per month||*FEV1 or PEF >80% predicted; PEF variability <20%|
|II: mild persistent||Symptoms more than 2 times per week, however not daily; attacks limit activities sometime; night time asthma attacks occur more often than 2 times per month||FEV1 or PEF >80% predicted; PEF variability 20 to 30%|
|III: moderate persistent||Daily symptoms; inhaler (beta-2 agonist) has to be used daily; attacks limit activities; asthma attacks occur more often than 2 times per week and last several days; night time asthma more often than 1 times per week||FEV1 or PEF >60 to 80% predicted; PEF variability >30%|
|IV: severe persistent||Symptoms continuously; physical activity significantly limited; frequent asthma attacks during the day and during the night||FEV1 or PEF <60% predicted; PEF variability >30%|
*FEV1 (= forced expiratory volume in 1 second, thanks to www.spirxpert.com for this link)
**PEF = peak expiratory flow (using peak flow meter)
1. Noble: Textbook of Primary Care Medicine, 3rd ed., Copyright © 2001 Mosby, Inc.
2. National Asthma Education and Prevention Program. Expert Panel Report II. National Heart, Lung and Blood Institute, 1997.
3. Rakel: Conn’s Current Therapy 2002, 54th ed., Copyright © 2002 W. B. Saunders Company
4. Murray & Nadel: Textbook of Respiratory Medicine, 3rd ed., Copyright © 2000 W. B. Saunders Company
5. Behrman: Nelson Textbook of Pediatrics, 16th ed., Copyright © 2000 W. B. Saunders Company
6. Merck Manual : Asthma (thanks to http://www.merckmanuals.com for this link)
7. Goldman: Cecil Textbook of Medicine, 21st ed., Copyright © 2000 W. B. Saunders Company
8. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.
9. Rakel: Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier