Module 7 pulmonary Flashcards
What is Asthma?
The only reversible airway bronchoconstriction,most often due to allergic stimuli (type I HSR)
There are different types of asthma and the order of the cards will follow the different types. The first type is Atopic (Extrinsic) Asthma, what are some features?
Much more common and is episodic
based on a familial predisposition to type I HSR to dust, pollen, animal dander and foods
Causes bronchial asthma, allergic asthma, allergic rhinitis and eczema (ectopic dermatitis)
What happens with the first exposure to a trigger in a person with atopic extrinsic asthma?
Sensitization: so antigen presentation and isotype switching from THO to TH2 because of IL4 and IgE production.
IgE binds to the surface of mass cells and basophils and you get mast cell degranulation
What happens with the second exposure to a trigger in a person with atopic extrinsic asthma?
Re-exposure to antigen induced cross linking of IgE on mast cells and basophils – brochoconstriction
- –production and activation of eosinophils (stimulated by IL-5), PMNs and T cells
- -epithelial cells are activated and recruit more TH2 cells and eosinophils = damage resp epithelium —- amplifies bronchospasm and edema
- -produces histamine, leukotrienes and Prostoglandins that cause bronchoconstriction and bronchospasms
Review: What are the TH2 cytokines?
IL4-stimulates IgE production by turning THO to TH2 (isotype switching)
IL5: activates eosinophils
IL-13: stimulates mucus production and promotes IgE production by B cells IgE coats mast cells = degranulation with Ag exposure
Review: What two diseases are associated with Eosinophils?
Asthma
Churg Strauss
Patients with extrinsic bronchial asthma are at risk of developing what disease if exposed?
Allergic bronchopulmonary aspergillosis: which is a type I and III HSR
What do patients with both types of bronchial asthma present with?
Expiratory wheeze, chest tightness, productive cough (Sputum), and SOB
In sputum cytology what do you see on a patient with atopic extrinsic asthma? pics on slide 5b
Curschmann Spiral (shredding of bronchial epithelial cells) (pseudostratified) Charcot layden crystals: MBP and eosinophilic cationic protein
On CXR what do you see in a patient with atopic extrinsic asthma?
Hyperinflated lung fields
What do you see on pulmonary function test and ABG for extrinsic asthma?
Pul function test: decreased FEV:FVC ratio and Increased TLC:RV
ABG: low O2 and Low CO2 and elevated pH because you are hyperventilating. If CO2 becomes high and patient becomes acidotic then patient is decompensating (getting tired) and about to die.
Now on histology, slide 5a, what do each of the arrows represent?
Green Arrow: Goblet cell hyperplasia no metaplasia
Black Arrow: thick BM
Yellow Arrow: eosinophils (inflammatory cells)
Blue arrow: bronchial SM hypertrophy
What is reversible and irreversible in atopic bronchial asthma?
So the changes seen on histology are irreversible
but the symptoms are reversible
—remember only reversible obstructive disease
—remember REID index is normal
How chronic bronchitis different from bronchial atopic asthma?
Chronic Bronchitis: no eosinophils, REID elevated, squamous metaplasia (Because cig smokers)
The next type of asthma is non atopic bronchial asthma Intrinsic. What are the causes?
Most common is viruses
and then aspirin
Explain how viruses cause non atopic bronchial asthma
Lower the threshold of the vago receptors (vago receptors bind acetylcholine and that increases PS response — bronchoconstriction
–give Albuterol (B2 agonist)–stimulates sympathetics — bronchodilation (but you can also give this to atopic bronchial asthma as well)
Explain how aspirin can cause non atopic bronchial asthma?
Inhibits COX and favors lipooxygenase — increases leukotrienes — bronchoconstriction
What are some differences in atopic and non atopic bronchial asthma
NO IgE
No family history
NO CHARCOT LEYDEN CRYSTALS
BUT DO SEE CURSCHMAN SPIRALS AND PMNs