Asthma Flashcards
What is the definition of asthma?
chronic (1) inflammatory disorder of the airways that is characterized by (2) episodic reversible bronchospasm resulting from an exaggerated response to a stimulus
What cells play major roles in asthma?
mast cells, eosinophills, and T cells
What is the long term consequence of chronic inflammation (this is what leads to the obstruction)?
remodeling of the airway
T or F: Asthma is curable
F: very manageable
Describe the epidemiology of asthma
- -2-7% of the pop has it
- -overall female > male but in childhood male > female
- -blacks > risk of asthma death
- -30-50% of kids will “outgrow” asthma
- -20-30% of adult onset asthma will experience remission
How is asthma classified?
intermittent = 1-2 episodes/year
persistent = > 1-2 episodes/year
-mild, moderate, severe
How is mild persistent asthma treated?
inhaled steroids
How is moderate persistent asthma treated?
inhaled steroids and long acting beta agonists (LABAs)
How is severe persistent asthma treated?
inhaled steroids, long acting beta agonists (LABAs), and leukotreine modifiers
*leukotreines cause constriction
What type of asthma treatment is assc with an increased in mortality?
LABA
What is the rescue medication for an acute asthma attack?
LABA
What is the most common type of asthma? What age group is it most common in?
extrinsic and kids
What is the pathophys of extrinsic asthma?
type I HS reaction: IgE response to environmental allergens
Triggering of response:
Ag recognized by Th2 cell which makes IL-5 and IL-5 and IL-13.
–IL-4 activates B cells to make IgE against Ag. IgE binds FcR and coats Mast cells. Mast cells degranulate and make IL-5 when exposed to Ag
–IL-13 promotes mucous production.
–Mast cell and Th2 cell IL-5 recruit and activate eosinophils.
Early/immediate response: minutes
-mast cell and eosinophil granule contents either directly or through neuronal reflexes… induce bronchospasm, increase vascular permeability and mucus production, and recruit additional mediator-releasing cells from the blood
Late phase: hours
the arrival of recruited neutrophils, eosinophils, basophils, lymphocytes, and monocytes are active and release more inflam mediates that cause more inflammation, mucous prduction, bronchoconstriction, and damage to epithelium in airways
What are common environmental allergens that cause extrinsic asthma?
house dust mites
cockroaches
pets (cell debris in their saliva)
mold
How is extrinsic asthma diagnosed?
wheal-and-flare reaction
T or F: infections can trigger extrinsic asthma
T
What triggers intrinsic asthma?
respiratory infection (rhinovirus, parainfluenze) and inhaled air pollutants (sulfur dioxide, ozone, nitrogen dioxide)
what is the epidemiology of intrinsic asthma
adult onset
Are skin tests + or - in intrinsic asthma?
negative
What is the pathophys of intrinsic asthma?
not sure but know that eosinophils are involved bc it is treated the same as extrinsic asthma
How can intrinsic and extrinsic asthma be differentiated?
IgE levels are only elevated in extrinsic also intrinsic is not allergen mediated so a skin test will be negative
What drugs can induce asthma
aspirin
NSAIDS
How does drug induced asthma present?
recurrent rhinitis and nasal polyps, urticaria, and bronchospasm
What is the suspected mechanism behind drug induced asthma?
aspirin and NSAIDS inhibit the COX pathway without affecting the lipoxygenase pathway. it is thought that this shifts the balance of production towards leukotrienes which cause bronchial spasm
What is the Tx for drug induced asthma?
leukotriene antagonists
How is occupational asthma differentiated from non-occupational/all other asthmas/?
pts feel better on vacations and on weekends
What causes occupational asthma?
exposure to fumes (epoxy resins, plastics), organic and chemical dusts (wood, cotton, platinum), gases (toluene)
Occupational asthma is (IgE or non-IgE) mediated reaction/
both
When does exercise induced bronchospasm occur?
usually AFTER not during exercise
What is the mechanism of exercise induced bronchospasm?
cooling and mucosal drying of airways during exercise is thought to trigger mast cell release of histamine
Howe is exercise induced bronchospasm treated?
pre-treatment with B agonist or cromolyn is effective
*slow warm-ups also help
T or F: coughing can be the only presenting symptom of athma
T: it is called Cough-Variant Asthma
Describe the history of a person with cough-variant asthma
history of chronic cough and exposure to irritants (smoke, fumes, exercise)
How is cough variant asthma diagnosed?
positive clinical response to treatment
Methacholine challenge test
What is nocturnal asthma? What is the pathophys?
asthma symptoms predominate at night during sleep due to decline in circulating catecholamines and cortisol (vagal tone predominates)
What is ABPA?
allergic bronchopulmonary aspergillosis = asthma due to asperigillus fumigatus via a type III IgE mediated response
What are the criteria for diagnosis of ABPA?
- poorly controlled asthma
- eosinophillia
- IgE > 1000ng/ml
What is the treatment for ABPA?
prednisone
What is airway hyperresponsiveness?
What does it lead to?
exaggerated bronchoconstrictive response by the airway to a variety of stimuli. It leads to
1. Airway inflammation
2. epithelial injury
3. neural mechanisms
4. intrinsic airway smooth muscle function
=AIRFLOW OBSTRUCTION
What mediators cause airway constriction?
Major Basic Protein (released by eosinophils)
Eosniphillic Cationic protien
Histamine (mast cells and eosinophils)
Leukotrienes and prostaglandins
What happens to the epithelium lining the airway in asthma?
- disruption of epithelium with loss of cilliated cells (denudation)
- increased permiability –> hyperresponsiveness
- transudation of fluids
- increased mucous and respiratory secretions
T or F: asthmatics have increased vagal tone with reflexive bronchocontriction
T: according to Muthiah….
What causes permanent narrowing of the airways?
airway remodeling (subepithelial fibrosis)
What determines the diameter of the airway?
edema mucous ASM contraction and hypertrophy inflam cell infiltrate airway remodeling
How does asthma and COPD compare? Onset Type of inflammation relevate lymphocytes relevant interleukins allergy history? reverisbility of bronchospasm during exacerbation
Asthma / COPD:
younger / older eosionophillic / neutrophillic CD4 / CD8 IL-5 / IL-8 usually present / not usual reverisble / varible and limited reversibility neutrophillic / eosinophillic
When a middle aged pt presents to you and their response is mainly neutrophillic, are you thinking asthma or COPD?
asthma
When a middle aged pt presents to you and their response is mainly eosinophillic, are you thinking asthma or COPD?
COPD
What are the symptoms of Asthma?
wheezing chronic cough noctournal cough/wheeze chest tightness sputum production SOB or wheezing that is seasonal/after exposure to allergens
What can exacervate asthma?
allergens, GERD, URI, exercise
What may cause a post infectious bronchial hyperresponsiveness for up to 6 weeks?
viral tracheobronchitis
What are signs of life threatening asthma?
accessory muscle use on presentation pulsus paradoxus signs of R heart strain (P-pulmonale on EKG) hypoxemia hypercapnia
What is the cause of death for a pt with asthma?
mucous plugging of airways = suffocation
When during the day is peak expiration flow rate (PEFR) normally highest? Why?
How is this different in an asthmatic?
highest at 4 PM due to increased levels of catecholamines and cortisol and lowest at 4AM due to lower levels of catecholamines and cortisol
in asthamtics the daily PEFR differs by > 20%… does this mean that there is greater than 20% change between morning and nighttime readings??? bc PEFR should not increase in asthmatics… CONFUSING SLIDE GRRRR
Describe the tests results that can be used to diagnose asthma
**this slide of his was super confusing
- spirometery: dec FEV1 and FEV1/FVC and FEF25-75 (all of which will reverse with admin of bronchodialtors)
- reversibility criteria: 12% improvement (in what? I dont know) with 200cc increase in FEV1 and/or FEC
- lung volumes: hyperinflation suggested by elevated RV, FRC, RV/TLC, and TLC
- gas exchange would be normal
Describe the Methacholine Challenge Test.
The patient breathes in nebulized methacholine to provoke bronchoconstriction via the M3 receptor. The degree of narrowing can then be quantified by spirometry. People with pre-existing airway hyperreactivity, such as asthmatics, will react to lower doses of drug.
HIgh negative predictive value = if you are negative you do probably do NOT have asthma
What are the asthma relievers?
Conrollers?
relievers = short acting B2 agonsits and anticholinergic
controllers (from 1st to last choice)
- inhaled corticosteriods
- inhaled LABA
- LT modifiers
- systemic steroids
- Anti IgE
