January 15, 2016 - Clinical Asthma Flashcards Preview

COURSE 3 > January 15, 2016 - Clinical Asthma > Flashcards

Flashcards in January 15, 2016 - Clinical Asthma Deck (14):

Asthma in Canada

About 8% of the population has asthma. (5-10% prevalence)

About 50% of people with asthma is poorly controlled.


Most Common Non-Communicable Pediatric Disease



Asthma Economics

It is the inverted pyramids.

10% of people with severe or uncontrolled asthma make up 54% of the cost spent on asthma. 70% of people with mild or controlled asthma make up only 13% of the cost.

If you can keep asthma under control, you will decrease cost. 


Pathophysiology of Asthma

Early stage has to do with mast cells and constriction of the airways.

Late stage has to do with infiltrates of lymphocytes, neutrophils, and eosinophils.


Can cause inflammation and edema, mucus and plasma exudation, smooth muscle contraction, and epithelial damage/shedding.


Asthmatic Airways

Asthmatic airways often have increased vasculature, are inflamed, and are edematous. These result in a compromise in airspace lumen.

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Correlation of Atopic Diseases

Asthma often correlates with other types of allergies. It os common to have overlap with allergic rhinitis and eczema.

If the patient has these, you want to get these under control first as they can be an excaberating factor.


Early and Late Asthmatic Response

Early phase is due to mast cell release.

Late phase is due to cellular infiltration.

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Potential Asthma Triggers

Infections - particularly viral respiratory

Irritants - tobacco and air pollution, noxious chemicals, cold air/exercise

Allergens - cats, dogs, dust, aspergillus, suphites, MSG

Drugs - aspirin/NSAIDs, beta-blockers

Miscellaneous - strong emotional response


Clinical Presentation of Asthma

Variable wheezing, dyspnea, chest tightness, cough.

May be worse at night or in the morning.



Demonstrating Varible Airflow Obstruction

Spirometry: for adults - less than 75% FEV1 and an increase of 12% or more after a bronchodilator has been applied with more than 200mL of increase. For children, less than 80% with an increase of 12% with bronchodilator.


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Methacholine  Challenge

Patient is exposed to increasing concentrations of methacholine.

You are looking for a 20% drop in FEV1, and the concentration where FEV1 drops 20% is known as the PC20.

PC20 <4mg/mL - consistent with asthma

PC20 >16mg/mL not consistent with asthma

PC20 >4-16mg/mL is indeterminate


Diagnostic Testing for Asthma

Pulmonary function testing - spirometry/peak flow as well as methacholine challenge is useful to aid in diagnosis

CBC - may show eosinophilia

IgE level - may be elevated


Asthma vs. COPD

Age of onset - asthma may be at any age but tends to be younger, and most cases of COPD are in patients over the age of 50

Smoking Hx - asthma may or may not have, but COPD is almost invariably a current smoker or an ex-smoker

Cough - asthma is often nocturnal, while COPD is often in the morning

Wheeze & Dyspnea - asthma is usually episodic, while COPD is more gradual and progressive

Peak Flow - Reduced and variable in asthma, while it is usually reduced and consistent in COPD

Bronchodilator trial - asthma often shows an increase in FEV1 while COPD will usually have no change

Steroid trial - asthma shows a good response, and COPD shows minimal


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