Asthma diagnosis

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Professor Professor Abdur-Rab Khan Abdur-Rab Khan MRCP- FRCP (UK) MRCP- FRCP (UK) Ayub Medical College Ayub Medical College Abbottabad Abbottabad

Transcript of Asthma diagnosis

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ProfessorProfessor

Abdur-Rab Khan Abdur-Rab Khan MRCP- FRCP MRCP- FRCP (UK)(UK)

Ayub Medical College AbbottabadAyub Medical College Abbottabad

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Diagnosis of AsthmaDiagnosis of Asthma

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HistoryHistory

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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

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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

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SpirometrySpirometry Recommended for the initial assessment of all

asthma suspects!

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> 15% increase in FEV1.0

after ß-2 inhalation

Hallmark of Asthma: Reversibility!

Spirometry

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Types of Flow Volume Curves

Normal Obstructive

Lit

ers

per

se

co

nd

Concavity

Asthma

Concavitypre-

bronchodilator

Improvedpost-bronchodilator

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Good Measurements Good Measurements are Essential!are Essential!

Acceptable Loop

Unacceptable Loop

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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

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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

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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%

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THANK YOU THANK YOU