Treating Asthma Flashcards
Which disease is the leading cause of lost school days in children and work days among adults is what?
asthma
How do we differentiate mild from severe asthma?
- mild: occasional symptoms, usually upon some sort of exposure
- sever: frequent attacks, especially at hight, which limit activity
Describe airway changes in those suffering an asthma attack.
- bronchial and tracheal constriction
- mucosal thickening from edema and cellular infiltration
- the net result is narrow airways filled with thick mucous plugs
During an asthma attack, what measures of airflow are likely to be reduced?
all indices of expiratory flow:
- FEV1
- FVC
- FEV1/FVC
- peak expiratory flow rate
What is FEV1?
the volume of air expired in the first second of forced expiration
What is FVC?
the volume breathed out from a maximally forced expiratory effort
During an asthma attack, which measures of airflow are likely increased?
- total lung capacity
- functional residual capacity
- residual volume
- DLCO (diffusion capacity for CO)
What is the difference between functional residual capacity and residual volume?
- functional residual capacity is the residual volume left during normal breathing
- residual volume is the residual volume left after maximally forced expiratory effort
What role do bronchodilators and anti-inflammatory agents play in the treatment of asthma?
- bronchodilators are short-term relievers
- anti-inflammatory agents are long-term controllers
How does the airway of an asthmatic individual differ from that of a healthy individual?
the airway of an asthmatic is hyper-responsive to inflammatory mediators released in response to allergens, cold, exercise, etc.
Which inflammatory cells are involved in the early and late phase of an asthma attack?
- early: primarily mast cells
- late: T-cells, mast cells, eosinophils, and neutrophils
Why do severe asthmatics often experiences more symptoms at night?
because PNS tone is highest at night, which means that bronchoconstriction is more likely
How is bronchoconstriction mediated by the autonomic nervous system?
vagal efferents release acetylcholine onto muscarinic receptors on bronchial smooth muscle
Through what two mechanisms can inhaled irritants cause bronchoconstriction?
- they can induce release of chemical mediators from mast cells
- they can stimulate afferent vagal nerves to initiate reflex bronchoconstriction
What second messenger system regulates bronchial tone?
cAMP
Through what mechanism does the sympathetic nervous system act on bronchial smooth muscle?
- B2-adrenergic receptors are activated, activating AC
- cAMP levels rise and induce bronchodilation
Do high intracellular cAMP levels support bronchodilation or bronchoconstriction?
bronchodilation
What role does PDE play in regulating bronchial tone?
it degrades cAMP, promoting bronchoconstriction
How do phosphodiesterase inhibitors function in the treatment of asthma?
they inhibit the degradation of cAMP, promoting bronchodilation
How does theophylline function in the treatment of asthma?
it is an adenosine receptor antagonists that inhibits adenosine from inducing bronchoconstriction
Name two molecular signals that serve to initiate bronchoconstriction.
- acetylcholine
- adenosine
Bronchodilators fail to treat what aspect of asthma pathology?
mucous formation, edema, and cellular infiltration
Why are inhaled B2 agonists like albuterol relatively safe with few side effects?
- because inhalation, if done correctly, is essentially a topical administration without systemic effects of the drug
- that which is swallowed is either poorly absorbed or subject to a high first pass effect
What effect does albuterol have on potassium?
it increases insulin release and therefore induces a hypokalemia
