Download Asthma lecture

ASTHMA
Victor Politi, M.D., FACP
Medical Director, SVCMC School of
Allied Health
What is Asthma?




Asthma is a chronic condition that occurs when the
main air passages of the lungs, the bronchial tubes,
become inflamed.
The muscles of the bronchial walls tighten and
extra mucus is produced, causing the airways to
narrow.
can lead to minor wheezing to severe difficulty in
breathing.
In some cases, breathing may be so labored that
an asthma attack becomes life-threatening
Definitions

Asthma
– Reversible airway obstruction
– Airway inflammation
– Increased bronchial hyperresponsiveness

Status Asthmaticus
– Severe airway obstruction developing
over days-weeks
The Respiratory System
Pathophysiology


Hallmark of Asthma -Bronchial wall
Hyperresponsiveness
Early Phase Asthma Reaction

Bronchoconstriction
– Antigenic Stimulation of bronchial wall
– Mast Cell Degranulation releases




Histamine
Chemotactics
Proteolytics
Heparin
– Smooth Muscle Bronchoconstriction
Pathophysiology

Late Phase Asthma Reaction: Bronchial
Inflammation
– Inflammatory Cells Recruited



Neutrophils
Monocytes
Eosinophils
– Release Cytokines, Vasoactives, Arachidonic acid
– Epithelial and Endothelial Cell inflammation
– Release of Interleukin 3-6, TNF, Interferongamma
Risk Factors

Family History
– One parent with asthma: up to 25% risk for child
– Two parents with asthma: up to 50% risk for child



Parental tobacco use
Associated aspirin or NSAID allergy
Classic Triad:
– Asthma, Nasal polyps, Aspirin allergy



RSV Bronchiolitis history
Strongly associated with later development of
asthma
Strenuous exercise in areas of high ozone
(pollution)
Types of Asthma





Extrinsic Asthma (Allergic)
Intrinsic Asthma (Non-allergic)
Mixed Asthma (Extrinsic and Intrinsic)
Occupational Asthma
Drug Induced Asthma
– Aspirin-induced Asthma
– NSAID-induced Asthma


Exercise Induced Asthma
Cough Variant Asthma
– Very common! (Especially in children)
Asthma Statistics



For reasons no one quite understands, the number
of asthma cases has risen dramatically during the
past decade, especially among children living in the
inner city.
Approximately 14 million Americans have asthma,
including more than 6 million children.
Asthma is the most common chronic illness of
childhood.
– Among young children, asthma is more common in boys
than in girls.
– After puberty asthma becomes more common in girls
Intrinsic Asthma
Non-allergic asthma

Pathophysiology
– Non-IgE, Non-allergic asthma

Precipitating Factors
– Irritant exposure

(Air Pollution, Fumes, Perfumes, Household cleaning agents,
Insecticides, paint, tobacco, cold air
– Infection

URI, purulent rhinitis, acute sinusitis
– GERD

Epidemiology
– Much more common in adults than children
– Onset age over 40 years old
Extrinsic Asthma
Allergic Asthma

Pathophysiology
– IgE mediated response to allergens



Immediate allergic reaction
Late-phase allergic reaction
Causes
– Indoor allergens




House –Dust mites (most common extrinsic allergen)
Animal proteins (animal dander)
Mold spores
Cockroaches
– Outdoor allergens


Pollens , mold spores
Epidemiology
– Much more common in children than adults
– Age Onset under 40 years old
Asthma Triggers
Asthma Triggers
Asthma Triggers
All Asthma attacks give a
warning

Warning signs and symptoms for adults can
include:





Increased shortness of breath or wheezing
Disturbed sleep caused by shortness of breath,
coughing or wheezing
Chest tightness or pain
Increased need to use bronchodilators — medications
that open up airways by relaxing the surrounding
muscles
A fall in peak flow rates as measured by a peak flow
meter
All Asthma attacks give a
warning

Warning signs and symptoms for
children may include
– An audible whistling or wheezing when the child
exhales
– Coughing, especially if the cough is frequent and
occurs in spasms
– Waking at night with coughing or wheezing
– Shortness of breath, which may or may not
occur when the child exercises
– A tight feeling in the child's chest
Asthma and Other
Conditions

Differentiating between asthma and chronic obstructive
pulmonary disease (COPD) such as emphysema and chronic
bronchitis can be especially challenging.

Asthma and COPD each cause similar symptoms.

Not uncommon for older adults — especially longtime smokers
— to have both conditions.

Various tests — including skin or blood tests for allergies, and
spirometry — can help determine whether asthma is present.
What is cardiac asthma?


Cardiac asthma isn't actually asthma.
It refers to the wheezing that's caused
by CHF
– Excess fluid in the lungs (pulmonary
edema) associated with heart failure
causes signs and symptoms such as
shortness of breath, coughing and
wheezing, which mimic asthma
Exercise Induced Asthma

Exercise-induced asthma — or exerciseinduced constriction of the bronchial tubes
(bronchospasm)
– a condition in which the airways narrow
significantly during vigorous exercise.

Typical Symptoms
– Cough, Wheezing, Shortness of breath, Chest tightness
– Typically symptoms present about 10 minutes after
stopping exercise
Exercise Induced Asthma


Exercise-induced wheezing or
shortness of breath is typical for
people who have chronic asthma.
But exercise-induced wheezing or
shortness of breath can occur when
sensitive airways constrict when
exercising, especially when combined
with cold air, low humidity or pollution.
Chronic Asthma or
Exercise Induced Asthma

Basic difference between chronic
asthma and exercise-induced asthma
– People with exercise-induced asthma
have symptoms only with physical
activity.
– People with chronic asthma often have
exercise-induced wheezing or shortness
of breath, but they may have asthma
symptoms at other times as well.
Exercise Induced Asthma
- Medications


The most common medications for exerciseinduced asthma are bronchodilators, which
are taken about 15 to 30 minutes before
exercising
Medications Include:
– Albuterol (Proventil, Ventolin)
– Pirbuterol (Maxair)
– Ipratropium and albuterol combination
(Combivent)
What's the difference
between asthma and COPD?

similar symptoms but very different
– Asthma causes reversible lung
inflammation,
– COPD causes irreversible lung damage
– It's important to distinguish between the
two conditions because they're treated
differently
What's the difference
between asthma and COPD?

Smoking history. Asthma may occur
in nonsmokers as well as in smokers.
But COPD is usually associated with a
long history of smoking
What's the difference
between asthma and COPD?

Symptoms
– Periodic wheezing and chest tightness,
especially at night, is typical of asthma.
– COPD is more likely to cause a daily
morning cough that produces mucus.
– In COPD, patients may develop a
permanently expanded barrel chest
because too much air is trapped in the
lungs.
Cough Variant Asthma

Chronic cough –
– Cough > 3 weeks
– Nonproductive
– Usually nocturnal – but can occur anytime




Occur any age group
PFTs –normal
Rule out other causes of chronic cough
TX
– Similar to common forms of asthma
Asthma Evaluation
Differential Diagnosis

General
– All that wheezes is not asthma!!
– However most recurrent cough and wheeze is asthma

Upper airway disease
–
–
–
–
–
–
–
–
–
Allergic rhinitis
sinusitis
Large airway obstruction
Foreign body
Vocal cord dysfunction
Vascular rings of laryngeal webs
Laryngotracheomalacia
Tracheobronchial-stenosis
Enlarged lymph node or tumor
Asthma Evaluation
Differential Diagnosis

Small Airway obstruction
–
–
–
–
–

Viral Bronchiolitis
Bronchiolitis obliterans
Cystic Fibrosis
Bronchopulmonary dysplasia
Heart disease
Other Causes
– Psychogenic cough
– GERD
– ACE inhibitors
Asthma Evaluation
History

General: History is not always accurate
– Confirm with PFTs every 3-6 month
– Patient may underplay symptoms
– 10% of patients do not recognize severe Symptoms of
their asthma



Age of onset and asthma diagnosis
Past history of respiratory failure or intubation
Recognize cohorts at additional risk
– Elderly
– Pregnancy
Asthma Evaluation
History

History of early life injury to airways
– Bronchopulmonary Dysplasia
– Parental smoking



Disease progression
Present management and response
Frequency of systemic corticosteroid use
– History steroid-induced complications

Comorbid conditions
– Chronic sinusitis
– Assess in all asthma patients
– Consider empiric treatment if refractory asthma
Asthma Evaluation
History


Family History (any asthma, allergic rhinitis,
etc.)
Social History
– Home characteristics




Heating and cooling system
Wood burning stove
Humidifier
Carpeting over concrete
– Smokers in home
– Daycare and school situation impacting
compliance
Asthma Evaluation
Signs: Respiratory distress




Tachypnea
Dyspnea
Anxiety
Accessory Muscle Use
– Intercostal muscle use
– Sternocleidomastoid use
– Scalenes Muscle use


Cyanosis in severe cases (lips)
Tachycardia
Asthma Evaluation
Radiology: chest x-ray

Indications
– Initial asthma diagnosis

Low yield in acute asthma exacerbations
– Abnormal findings at presentation: 5%
– Abnormal findings if no improvement in 12 hours: 34%

Status Asthmaticus or no acute asthma
improvement
– Excludes other diagnoses


CHF
Pneumonia
– Excludes complications


Pneumothorax
Pneumomediastinum
Asthma Evaluation
Labs

ABGs
– Hypoxemia
– Hypercarbia (or normal CO2) with decompensation

CBC
– Eosinophilia may be present
– Increased Levels of IgE may be present

Sputum Sample
–
–
–
–
May show casts of small airways
Thick mucoid sputum
Curschmann's spirals
Charcot-Leyden crystals
Asthma Evaluation
Other Diagnostic Tests

PFT’s – Pulmonary Function Testing
– Spirometry
– Methacholine Challenge
What are PFT's?



Pulmonary function testing is one of the
basic tools for evaluating a patient's
respiratory status.
In patients with suspected pulmonary
disease, it is often the first diagnostic test
employed in the work up.
Pulmonary function tests (PFT's) are also
used for pre-operative evaluation, managing
patients with known pulmonary disease, and
quantifying pulmonary disability
PFT- Spirometry




A versatile test of pulmonary physiology.
Reversibility of airways obstruction can be
assessed with the use of bronchodilators.
After spirometry is completed, the patient is
given an inhaled bronchodilator and the test
is repeated.
The purpose of this is to assess whether a
patient's pulmonary process is
bronchodilator responsive by looking for
improvement in the expired volumes and
flow rates
PFT- Spirometry


spirometry can be used to detect the
bronchial hyperreactivity that characterizes
asthma.
By inhaling increasing concentrations of
histamine or methacholine, patients with
asthma will demonstrate symptoms and
produce spirometric results consistent with
airways obstruction at much lower threshold
concentration than normal
PFT- Spirometry



Normal values vary depending on
gender, race, age, and height.
It is therefore not possible to interpret
PFT's without such information.
There is no single set of standard
reference values, however, and
"normal" varies with the reference
value used in each laboratory
PFT- Spirometry
Definitions





FEV1 - forced expiratory volume 1 - the volume of
air that is forcefully exhaled in one second.
FVC - forced vital capacity - the volume of air that
can be maximally forcefully exhaled
FEV1/FVC - ratio of FEV1 to FVC, expressed as a
percentage
FEF25 - 75 - forced expiratory flow - the average
forced expiratory flow during the mid (25 - 75%)
portion of the FVC
PEF - peak expiratory flow rate - the peak flow rate
during expiration
PFT- Spirometry


In general, a > 12% increase in the FEV1
(an absolute improvement in FEV1 of at
least 200 ml) or the FVC after inhaling a
beta agonist is considered a significant
response.
However, the lack of an acute
bronchodilator effect during spirometry does
not exclude a response to long term therapy
Mild Obstruction Flow Volume
Normal Flow Volume
Loop
Asthma Medications

Two general types of asthma
medications
– Anti-inflammatory

Corticosteroids reduce swelling & mucous in
airways
– Bronchodilators

Relax muscle bands around airways allowing
more air to flow, also increases mucous
movement
Quick Relief Medications

Short acting beta-agonists
– (bronchodilators that are the drug of choice to relieve
asthma attack and prevent exercise-induced asthma
symptoms)

Anticholinergics
– (bronchodilators used in addition to short-acting beta
agonists when needed or as an alternative to these drugs
when needed)

Systemic corticosteroids
– (anti-inflammatory drug used in an emergency to get rapid
control of the disease while initiating other treatments and
to speed recovery)
Status Asthmaticus
Emergency Management of
Asthma Exacerbation
Indications of severe
attack





Breathless at rest
Hunched forward
Talking in words rather than sentences
Agitated
Peak flow rate < than 60% of normal
Status Asthmaticus

A medical emergency in which symptoms
are refractory to initial bronchodilator
therapy
– Symptoms: chest tightness, rapidly progressive
shortness of breath, dry cough, and wheezing.
– Typically, patients present a few days after the
onset of a viral respiratory illness, following
exposure to a potent allergen or irritant, or after
exercise in a cold environment.
Asthma Exacerbation
Management

Step 1: Initial Assessment
– Routine asthma evaluation as previously
mentioned
– Vital Signs (heart rate, respiratory rate, Peak
Expiratory Flow Rate (PEF) or FEV1
– O2 saturation
– Respiratory Status




Lung auscultation
Assess accessory muscle use
Chest x-ray has low yield in acute exacerbations
ABGs
Asthma Exacerbation
Management

Inhaled short acting Beta Agonist (nebulized)
– One dose up to every 20 minutes for one hour

Anticholinergic (Ipratropium bromide or Atrovent)
– Add to nebulized albuterol
– Indication: FEV1 or PEF <50% of predicted (Severe)

Systemic Corticosteroid (PO or IV Indications)
– Severe episode (FEV1 or PEF <50% predicted)
– No immediate response
– Oral corticosteroid recently taken by patient

Oxygen indications
– Adults: O2 saturation <91%
– Children: 02 saturation <96%
Additional measures for severe
exacerbation

Nebulized Albuterol w/Atrovent
– hourly or continuous


Systemic corticosteroid
Epinephrine 0.01 mg/kg up to 0.3 mg SC
– May be repeated every 5 minutes

Oxygen 100% (warm, humidified) by non-rebreather mask
Two Intravenous Lines

Consider :

– Aminophylline or Theophylline
– Magnesium 40 mg/kg up to 2 grams IV for 1 dose



Rapidly effective in pediatric asthma exacerbations
Also shown effective in severe adult acute asthma
Some studies question benefit
Additional measures for severe
exacerbation –
Intubation/mechanical ventilation
– Intubation is best done semi-electively before crisis
– Intubation criteria are based on clinical judgment
– Oral intubation is preferred


Lower resistance and easier suctioning
Lower incidence of sinusitis
– Indications





Impending or actual respiratory arrest
Extreme fatigue
Altered mental status
Significant respiratory distress
Severe respiratory acidosis & metabolic acidosis
Medications To Be Wary Of with
Asthma Patients

Many adults take multiple prescription and overthe-counter medications to treat a variety of
conditions. Some medications may trigger or
worsen asthma symptoms.
– Angiotensin-converting enzyme (ACE) inhibitors

Won’t directly trigger asthma, can produce persistent cough
causing increased wheezing
– Beta blockers
– NSAIDs

can trigger severe and even fatal asthma attacks
Asthma Management
Goals
Asthma Management
Goals


Medical professionals need to be alert
to the signs/symptoms of asthma
They must be able to treat asthma
cases in a timely manner to avoid
worsening of the condition and/or the
development of status asthmaticus

Questions?