Asthma Flashcards
what is the definition of asthma?
<b>Chronic, inflammatory disorder of the airways characterized by:</b>
- Paroxysmal (intermittent) symptoms of cough, wheezing, dyspnea & chest tightness, usually related to specific trigger
- Airway narrowing that is partially or completely <b>reversible</b>
what is one of the most common chronic diseases of childhood?
asthma
who are death rates from asthma highest in?
African Americans 15-24 y/o b/c more triggers for asthma in inner city areas and AA’s have unequal access to medical insurance
what are asthma risks?
Gender: boys > girls (in childhood)
Socioeconomic status: poverty (esp in urban settings)
Food allergies (associated with intubations for asthma) fatal asthma Family history of asthma
<b>***Atopy</b>
what is atopy?
A genetic disposition to develop an allergic reaction and produce elevated levels of IgE upon exposure to an environmental antigen and especially one inhaled or ingested
what is the pathophysiology of asthma?
airflow obstruction - part from smooth muscle constriction & part from inflammation
<b>-Smooth muscle constriction around airways (can be life threatening)</b>
-Airway wall edema
-Intra-luminal mucus accumulation
<b>-Inflammatory cell infiltration of submucosa & basement membrane thickening</b> (eosinophils, activated helper T cells, mast cells & neutrophils) -> all come to area as part of immune response
what is fatal asthma?
- Severe collagen deposition of basement membrane
- Desquamation of epithelial lining with loss of ciliated cells lungs don’t clear well & have to get intubated
- Mucosal edema
- Airway smooth muscle hyperplasia/hypertrophy adds to luminal narrowing
- Luminal plugging with inflammatory cells
-Not always fatal
<b>Common in people with food allergies</b>
what are the main physiologic consequences of asthma?
- Chronic airway inflammation
- Reversible or partially reversible bronchoconstriction
- Increased airways hyperresponsiveness to a variety of stimuli
what are classic symptoms of asthma?
Nonspecific sx’s
- Intermittent dyspnea
- Cough (persistent)
- Wheezing (sudden onset or persistent)
what are additional features of asthma?
- Chest tightness
- Colds that take >10dys to resolve (URI they can’t get rid of)
- Apparent triggers (animals, tobacco smoke, perfume)
- Symptoms awaken patient from sleep
- Exertional symptoms (i.e. exercise induced asthma)
- Seasonal (pollen, mold, viruses) -> common triggers
- Poor school performance & fatigue (sleep deprivation)
what is the cough in asthma like?
Usually <b>‘dry hacking’ (non-productive)</b>
- Nocturnal (Big question to ask patients – need to know if waking up at night b/c classic for asthma)
- Seasonal
- Response to specific exposures (cold air, exercise)
- Lasts >3weeks
<b>Frequently the sole presenting complaint</b>
what are the common triggers of asthma?
pollens, viral URIs, exercise
what is something you should always ask an asthma pt when taking history?
about previous intubations
-if they have been, means they have <b>fatal asthma</b>
vital signs for asthma
usually normal.
Possibly tachypnea, hypoxia if acute flare
general signs of physical exam for asthma
typically, no acute distress but respiratory distress if acute flare, <b>can’t speak full sentences without stopping to breath</b>, tripod position, accessory muscle use
lungs on physical exam for asthma
widespread, high-pitched, musical <b>wheeze</b> although wheeze is usually absent between exacerbations
Asthma patient who is stable and not having an acute flare lungs will be clear
when is the wheeze of asthma heard?
initially with <b>expiration</b> but in severe cases also with inspiration
what does critically severe asthma do to the breath sounds?
Critically severe asthma causes decreased breath sounds “silent chest/absent breath sounds” (medical emergency)
extra-pulmonary physical exam findings associated with asthma?
- Pale, swollen nasal turbinates suggestive of allergic rhinitis
- Nasal polyps (in adults)
- Atopic dermatitis (eczema)– risk factor for asthma
dx studies for asthma
PFTs (spirometry w/bronchodilator response testing or bronchoprovocation challenge - methacholine - elicits asthma)
Peak expiratory flow (done with flow meter)
CXR (to r/o other causes of SOB) - should be normal if nothing else going on
Allergy skin testing to identify triggers
what FEV1 & FEV1/FVC ratio be for airway obstruction?
FEV1 decreased
-b/c having trouble getting air out d/t bronchoconstriction
<b>FEV1/FVC <0.7 (<70%) – KNOW!!!</b>
what does spirometry measure?
Measures forced expiratory volume in one second (FEV1)
Measures forced vital capacity (FVC)
what is vital capacity?
maximum amount of air a person can expel from the lungs after a maximum inhalation
if baseline spirometry demonstrates airway obstruction, what do you administer? An increase in the FEV1 of ___ and greater than ___ suggests what?
If baseline spirometry demonstrates airway obstruction -> administer albuterol 400mcg by metered-dose inhaler-> repeat spirometry ten minutes after administration.
An increase in the FEV1 of >12% and greater than 0.2 L suggests acute bronchodilator responsiveness
-Means reversible condition aka asthma
