EXAM3/CH20- Asthma Flashcards
what type of disorder is asthma
chronic inflammatory disorder
what occurs in asthma
airway hyperresponsiveness causes recurrent episodes of airflow obstruction
-if you have asthma, your airways will respond more to things like smoke, pollen, etc.
quicker + more pronounced response
asthma symptoms
-wheezing
-breathlessness
-chest tightness
-coughing
when do asthma episodes typically occur
particularly at night or in the early morning
-reversible either spontaneously or with treatment
wheezing
high pitched sound during inspiration + expiration
what is typically the first + last symptom to occur/resolve in an asthma attack
cough
spontaneous reversal
if you remove the stimulus (smoke, pollen, etc.)
disease scope of asthma
-a worldwide problem with an estimated 300 million affected
-22 million Americans affected
-5% increase per year in the world
-higher in some populations (23% of inner-city African Americans vs. 5% of Caucasians)
when does most childhood asthma begin
infancy (less than 3 years of age)
asthma pathophysiology
-host factors (innate immunity, genetics) predispose to airway hyperresponsiveness
-stimuli are environmental (airborne allergens, viral respiratory infections, cold air)
-CD4 lymphocytes promote inflammation by activating eosinophils + mast cells
-cellular interactions are regulated by a cascade of inflammatory mediators
____ promote inflammation by activating ____ + ____
CD4 lymphocytes
eosinophils
mast cells
-all involved in the inflammatory cascade that results in bronchoconstriction
asthma- acute process (minutes to hours)
-airway inflammation stimulates bronchoconstriction, mucus secretion, + edematous swelling
-these obstruct airflow causing asthma ‘attacks’ which are episodic + (usually) reversible
bronchoconstriction
tightening of the airways
edematous swelling
the tissue itself accumulates fluid + begins to swell
asthma- chronic process (months to years)
-airway epithelium is damaged
-fibrosis due to collagen deposition
-smooth muscle hypertrophy, hyperplasia
-angiogenesis
what does collagen deposition do to the lungs
causes lung tissue to become stiffer
hyperplasia
increase in cell number
angiogenesis
growth of blood vessels
what cells line the airways
columnar epithelial cells
epithelial cells have ____
cilia
cilia
little hairs that are active + beat to move mucus up + out of lungs to clear foreign material from airways
-the mucus that exists in the lungs is made by the lungs by mucus glands (see dark epithelial invagination to the left of image)
-mucus is sticky so it captures dust + other foreign matter
-the cilia will then beat the mucus out of the lungs so you can swallow it or spit it out
-“mucociliary escalator”- rids lungs of foreign matter
what do blood vessels in mucosa do
bring nutrients to tissue + remove waste from the cells
how are smooth muscle cells shaped
spindle shaped
-can constrict to narrow the airway
how does tissue of chronic asthmatic compare to normal
-top layer of epithelium is damaged
-much more mucus
-little dust-looking particles in mucosa that are inflammatory cells
-increased + LARGER spindle shaped smooth muscle
-baseline caliber is reduced
-thicker mucosa
-mucus obstricting airway
-small hole for air to go through
asthma symptoms
-wheezing
-breathlessness
-cough
-chest tightness
what can impede asthma diagnosis
intermittent episodes
potential stimuli of asthma
-allergens
-seasonal rhinitis
-dust mites
-smoke
-strong fumes
-cold air
-exercise
diagnosing asthma
-medical history
-physical exam of the chest
-spirometry
spirometry
quantitatively measures how the lungs function
-measures the rate of flow out of a persons lungs when they make a maximal effort
-ask pt to take in as much air as they can + blow out as hard as they can for as long as they can
FEV1
forced expiratory volume in 1 second
what is the most common indicator of asthma
FEV1
FVC
forced vital capacity
-max amount of air you can blow out
FEV1/FVC
you can normalize the FEV1 based on size of person based on “forced vital capacity”
pharmacologic challenge
ask person to inhale a allergen/inflammatory stimulus to see if they have a normal or exaggerated response in spirometry
what FEV1 is consistent with asthma
less than 80% of predicted
what FEV1/FVC is consistent with asthma
less than 65% of predicted
other clinical assessments for diagnosing asthma
-chest roentgenogram (x-ray)
-sputum production
-consider other causes for symptoms (e.g., pneumonia, pneumothorax, congestive heart failure)
chest roentgenogram
x-ray
sputum production
we look for how much inflammatory cells the pt is producing in the sputum
pneumothorax
when you get air in your chest + the lung collapses
what can cause many of the lung symptoms we see
primary disease of the heart
-due to back pressure that causes fluid in the lungs
what MUST be done to diagnose asthma
pulmonary function tests
-you cannot assume asthma because of other diagnoses
exercise testing for asthma
used to assess a decline in exercise tolerance that is unrelated to airflow limitation
-not done to diagnose
what type of exercise test would be done
symptom-limited incremental test
-often times SOB stops test
what measurements may be taken during exercise testing
-oxyhemoglobin saturation
-heart rhythm (ECG)
-metabolic cart (VO2, VCO2, anaerobic threshold)
contraindications for exercise testing
-acute bronchospasm
-exercise-induced bronchoconstriction (EIB)
-chest pain
-elevated shortness of breath
-severe exercise deconditioning
-orthopedic limitations
asthma treatment
focus on asthma control using therapeutic interventions that minimize the frequency + severity of symptoms + are acceptable to the patient
preventing EIB (exercise induced bronchoconstriction)
-a mask or scarf over the mouth/nose may be helpful to reduce cold-induced EIB
-people that don’t respond to the nonpharmacologic approach can use pharmacologic intervention prior to exercise
-exposure to cold air, low humidity, or air pollutants should be minimized
-intermittent exercise or lower-intensity sports performed in the presence of warm, humid air are generally better tolerated
what does asthma represent
airway narrowing secondary to airway inflammation
what does airway hyperresponsiveness exaggerate
the allergic response to environmental risk factors, exercise, + cold air
what do asthma treatment strategies focus on
prevention of acute episodes rather than reversal
what is common is asthmatics
exercise limitation + decreased levels of fitness
how can fitness be improved for asthmatics
using appropriate medication + conditioning regime
