Asthma diagnosis
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Transcript of Asthma diagnosis
ProfessorProfessor
Abdur-Rab Khan Abdur-Rab Khan MRCP- FRCP MRCP- FRCP (UK)(UK)
Ayub Medical College AbbottabadAyub Medical College Abbottabad
Diagnosis of AsthmaDiagnosis of Asthma
HistoryHistory
Peak Expiratory Flow Rate Peak Expiratory Flow Rate (PEFR)(PEFR)
Measures how fast a person can exhale air
Requires a peak expiratory flow monitor
OmronMini-Wright AM2 Plus
PEFR VariabilityPEFR Variability
Asthma Diagnostic Clues:
• PEF Variability > 20%(basis: home monitoring 2-4x/day for 1-2 weeks)
• Improvement in baseline PEF by 20% after a 2-week therapeutic trial
PEFmax - PEFmin
PEFave
(pm, post-bd) (am, pre-bd)% Variability = X 100
0
50
100
150
200
250
300
350
1 2 3 4 5 6 7Days
PE
FR
(L
/min
)
pm PEFR
am PEFR
SpirometrySpirometry Recommended for the initial assessment of all
asthma suspects!
> 15% increase in FEV1.0
after ß-2 inhalation
Hallmark of Asthma: Reversibility!
Spirometry
Types of Flow Volume Curves
Normal Obstructive
Lit
ers
per
se
co
nd
Concavity
Asthma
Concavitypre-
bronchodilator
Improvedpost-bronchodilator
Good Measurements Good Measurements are Essential!are Essential!
Acceptable Loop
Unacceptable Loop
Is it Asthma?
Determine that the patient is experiencing episodic symptoms of airflow obstruction
Demonstrate that the obstruction is at least partially reversible
Exclude alternate diagnoses
Asthma wheezing
Lung Disease Overlap
Chronic Bronchitis
cough+sputum
Emphysema breathlessness
Airway Remodeling in Asthma
Denudation of the airway epithelium
Collagen deposition beneath the basement membrane
Edema
Mast cell activation
Inflammatory cell infiltration
COPD
Classifying Severity: BASED ON SYMPTOMS & LUNG FUNCTION
DaytimeSymptoms
Exacerbations Nightattacks
11
22
33
44
IntermittentIntermittent• <1x a week • Brief
MildMildpersistentpersistent
• >1x a week but < 1x/day
• May affect activity & sleep
ModerateModeratepersistentpersistent
• Daily • May affect activity & sleep
SevereSeverepersistentpersistent
• < 2x a month
• > 2x a month
• > once a week
• Frequent• Daily • Frequent• Limits
physical activity
FEV1 or PEF
• > 80% predicted• Variability < 20%
• > 80% predicted• Variability 20-30%
• > 60-80% predicted
• Variability > 30%
• < 60% predicted• Variability > 30%
THANK YOU THANK YOU