Asthma Flashcards
Asthma
Chronic d/o characterized by recurring episodes of airway obstruction d/t smooth muscle hyperresponsiveness and mucosal inflammation
Epidemiology of Asthma
-affects ~1/10 5-17yo
-boys > girls; women > men
-Puerto Rican > Black > White > Mexican
-Complete remission occurs in 1/4 of kids (often near puberty)
-if sx onset 50yo+, consider other dx
MC stimuli of Asthma attacks
-ragweed
-animal dander
-house dust (dust mites and cockroaches)
-mold
-exercise, esp in cold air
*LOTS of others (RSV, rhinovirus, sulfiting agents, tartrazine (yellow 5), reflux, nonselective BB, ACEI, ASA, menstrual phases)
What are 2 other conditions often associated with Asthma
Atopic dermatitis (eczema)
Seasonal allergies
*if FH of either consider asthma risk
Asthma: typical S/S on lung exam
-wheezing (“whistling” on expiration)
-cough (usu worse at night)
-dyspnea
-chest tightness (trapped air)
Asthma: Ominous signs (more concerning)
-hyperresonance w/ percussion
-tachypnea & tachycardia
-use of accessory muscles
-prolonged expiratory phase
-quiet chest (lack of air mvmt)
-pulsus paradoxus
Asthma: PE findings (other than lung exam)
-pale, swollen nasal mucosa & cobblestoned posterior pharynx suggest allergic rhinitis
-atopic dermatitis in a flexural distribution
-nasal polyps (check for ASA sensitivity!!)
Asthma: Dx tests
PFT (measures lung volume, capacity, flow rate, gas exchange):
1. spirometry (MC)
2. plethysmography
*measures FRC, TLC, FEV1, FVC, FEF (Forced expiratory flow = avg forced expiratory rate during mid-FVC/aka forced expiration)
What are expected values of FEV1, FVC, and FEV1/FVC in obstructive & restrictive pulm dz?
OBSTRUCTIVE:
low FEV1
normal FVC
low FEV1/FVC
RESTRICTIVE:
variable FEV1
low FVC (little air inspired initially)
high FEV1/FVC ratio
Spirometry: Flow-Loop Volume Patterns
Y-axis: flow rate
X-axis: volume
*most useful in dx obstruction (i.e. decreased expiratory flow)
OBSTRUCTIVE: scoop on expiration, high volume (shift left)
RESTRICTIVE: smaller volume overall
What is the “gold standard” dx test for asthma
Measurement of airway reactivity before and after a methacholine or histamine challenge (triggers asthma)
-only perform is spirometry is normal or if atypical sx (e.g. cough is only sx)
How is allergy testing used in dx of asthma
Allergy skin testing may identify triggers, but will NOT make the asthma dx
NAEPP recommendations for preferred step therapy in asthma pts 12yo+ (KNOW THIS)
Step 1 (Intermittent): SABA prn
Step 2 (mild persistent): daily low-dose ICS & SABA prn OR concomitant ICS & SABA prn
Step 3 (moderate persistent): daily & prn low-dose ICS-formoterol (SMART)
Step 4 (severe persistent): daily & prn medium-dose ICS-formoterol (SMART)
Step 5 (severe persistent): daily medium- to high-dose ICS-LABA + LAMA; and SABA prn
Step 6 (severe persistent): daily high-dose ICS-LABA + oral systemic corticosteroids and SABA prn
Classification of Asthma Severity by Sx and Lung Fxn when not on tx (intermittent, mild persistent, moderate persistent, severe persistent - day & night sx, FEV1 value, 1st line tx)
INTERMITTENT
Day sx: 2 or < days/wk
Night sx: 2 or < nights/mo
FEV1: >80% predicted
Tx: SABA prn
MILD PERSISTENT
Day sx: 3-6 days/wk
Night sx: 3-4 nights/mo
FEV1: 80%+ predicted
Tx: low-dose ICS
MODERATE PERSISTENT
Day sx: daily
Night sx: >1/wk but not nightly
FEV1: 60-80%
Tx: low-dose ICS-LABA or medium-dose ICS
SEVERE PERSISTENT
Day sx: throughout day
Night sx: often nightly
FEV1: <60%
Tx: medium-dose ICS-LABA –> high-dose ICS-LABA –> high-dose ICS-LABA + oral corticosteroids
Asthma: Management (drugs designed to relax tracheobronchial smooth muscle)
-beta-adrenergic agonists
-theophylline
-anticholinergics
