Download - Pediatric Asthma and Bronchiolitis
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2009/9/3
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Chronic disease of the tracheobronchial treecharacterized by airway obstruction,inflammation, and hyperresponsiveness
Generally reversible with appropriate,aggressive therapy
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4.8 million children younger than 18 years of age Prevalence of asthma has increased in all age groups
by 40 percent in the last decade Risk factors associated with the development of
asthma
low birth weight family history of asthma urban household low-income household race (children of African-American, Asian, and Hispanic
descent
Most children presenting with asthma do so beforeage 8 male predominance in the prepubertal age group ratio equalizes during adolescence
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Bronchial hyperreactivity genetic basis
usually initiated by environmental factors
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Asthma is a two-stage process bronchoconstriction due to histamine and
leukotriene release (early stage)
airway mucosal edema with mucous plugging (late
phase)
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Children are at higher risk of respiratoryfailure than an adult Increased compliance of the infant rib cage and
immature diaphragm contributes to increased work
of breathing and respiratory muscle fatigue Young lung tissue lacks elastic recoil and is more
prone to atelectasis
Airway walls are relatively thicker and result in
greater narrowing with bronchoconstriction
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Avoid delays in treatment Brief physical examination should be
performed before a detailed history isobtained
Examination of vital signs
Supplementary oxygen administration
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After initial stabilization, perform a completeexamination assess ventilation, accessory muscle use, and work of
breathing
nasal flaring, foreign bodies, and concurrent sinusitis "musical" polyphonic inspiratory and expiratory wheezes
may not always be present on lung examination and arenot prognostic of severity of disease
Extremities should be inspected to assess cyanosis and
clubbing Complete history (aspiration, choking, possible
ingestion should be included for all ages)
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Peak expiratory flow rate (PEFR) monitor response to acute treatment ongoing assessment and management of asthma values in liters per minute are based on the child's height decreased by 25 percent once wheezing is detected by
stethoscope PEFR of less than 50 percent indicates severe obstruction,
and less than 25 percent indicates possible hypercarbia In the ED, PEFR is an excellent tool to evaluate mild asthma
or for reevaluating patients after treatment Limited by patient cooperation in children younger than age
5 may not be feasible during an acute exacerbation
Forced expiratory volume in 1 s (FEV1) correlates with the degree of airway obstruction
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ABGA should be obtained in children with impending respiratory failure Hypoventilating if PEFR is less than 30 percent of predicted not responding as expected to treatment
Complete blood count and chemistries usually unnecessary unless there is a concurrent febrile
illness or coexisting disease
Chest x-ray not recommended routinely new-onset asthma, for severe episodes requiring
admission, or if pneumonia, pneumothorax, foreignbody, or pneumomediastinum are in the differentialdiagnosis
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Upper and lower respiratory causes Nonrespiratory causes
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cause bronchial smooth muscle relaxation continuous aerosolized therapy with albuterol
is safe, fast, and effective
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Unresponsive to the preceding therapy orrespiratory distress increases
Administered while intravenous lineplacement is attempted
0.01 mL/kg aqueous epinephrine 1:1000 to amaximum of 0.3 mL
may be repeated every 20 to 30 min for a
total of three doses
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Inhibit the secretion of inflammatory leukotrienes andprostaglandins Prevent and reverse the increase in vascular
permeability that leads to airway edema Early administration during the course of an acute
exacerbation is recommended for all patients unless the PEF is greater than 50 percent and there is animmediate response to the first treatment
when exercise-induced attacks occur in a previously wellchild
Dose : 2 mg/kg
There is no real advantage to the administration ofintravenous over oral glucocorticoids in the acutesetting
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Most children presenting in statusasthmaticus will be dehydrated because ofincreased insensible losses
Administer a bolus of fluid 20 mL/kg of NS
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Prevent bronchoconstriction induced by cyclicguanosine monophosphate
Additive benefit when used with albuterol
Ipratropium is a safe drug with few side effects and
may be given to patients of all ages The dosage of nebulized ipratroprium bromide is
as follows: Adolescents >14 years of age: 500 mcg in an initial
nebulization Children up to 14 years of age: 125 ~ 250 mcg in an initial
nebulization
Neonates: 25 mcg/kg in an initial nebulization
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Magnesium Sulfate exact mechanism of action is unknown tocolytic effects of magnesium sulfate on uterine smooth
muscle improvement in short-term pulmonary function given as 25 to 50 mg/kg IV over 20 min; this may be
repeated once Maximum dose for children is 2 g
Heliox generally available as 80:20 or 60:40 mixtures of
helium and oxygen
recommended for the asthmatic who does not improvewith conventional treatment but in whom intubation isnot imminent
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Theophylline competitive phosphodiesterase inhibitor
no longer used routinely
reserved for patients who clearly respond to it or
for those who remain refractory to other modes oftreatment
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Children responding well to conventionaltherapy may be discharged after 2 to 4 h oftreatment
Short ED observation period is recommended
for patients with an incomplete response butacceptable PEFR
Detailed discharge instructions should outlinemedication administration, inhaler use, and
follow-up All children should be referred to their
pediatrician for follow-up within 24 h
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Inflammation of the bronchioles Clinical syndrome of wheezing, chest
retractions, and tachypnea in childrenyounger than age 2 years
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Peak prevalence is from late October to May. Peak age of incidence in urban populations is
2 months and results in hospitalizationslasting 5 to 7 days
Disease in older children is usually milder
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Respiratory syncytial virus (RSV) causes 50 to70 percent of clinically significantbronchiolitis transmitted by direct contact with large droplets of
secretions and self-inoculation by contaminatedhands via the eyes and nose no significant transmission occurs by small-particle
aerosol
Non-RSV bronchiolitis is caused by
infiuenzavirus, parinfluenzavirus, echovirus,rhinovirus, Mycoplasma pneumoniae andChlamydia trachomatis
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Peripheral airway narrowing and variableobstruction Mucous plugging
necrosis of the respiratory epithelium and destruction
of ciliated epithelial cells Submucosal edema
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Symptoms range from minimal rhinorrhea tobronchiolitis or pneumonia and respiratoryfailure
Infection begins with nasal discharge,pharyngitis, and cough
Fever accompanies the first few days ofillness
Symptoms reach a peak at 3 to 5 days,generally resolving in 2 weeks
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Physical findings tachypnea greater than 50 to 60 breaths/min
tachycardia
mild conjunctivitis
chest retractions prolonged expiration with hyperresonant chest
wheezing
hypoxemia
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Suggested by clinical presentation, patient age,and history of RSV exposure or communityepidemic.
Immunofluorescence assays currently availableare extremely sensitive but not necessary for allpatients
Complete blood counts and chemistries may notbe helpful in diagnosis
Chest radiography to rule out pneumonia is
indicated for children with concurrentcardiopulmonary illness or those who are ill-appearing and hypoxemic
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Treatment is mainly supportive, the mostimportant therapy being supplementalhumidified oxygen
Increased insensible fluid loss occurs fromincreased work of breathing and can causesignificant dehydration that warrants a NS bolus
Fever should be controlled with acetaminophenor ibuprofen
Antibiotics should be reserved for identifiable
bacterial infections Workup for occult bacteremia is not required
unless they appear toxic
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Nebulized epinephrine effective treatment for wheezing of bronchiolitis found to reduce hospitalizations in children with
bronchiolitis compared with albuterol It can be used safely in hospitalized children up to every
2 h as a 0.1% solution (0.5 mL in 3.5 mL of NS) If used in the ED, recommend an observation period of 4
h before a disposition decision is made Generally, infants and children showing minimal
response or deterioration after a single treatment will
require hospitalization Albuterol and Ipratropium
limited role for bronchodilator therapy in the treatmentof bronchiolitis
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Glucocorticoids Controlled studies have failed to demonstrate any
proven benefit to the use of glucocorticoids
Ribavirin decrease viral protein synthesis improvement in oxygenation
those with immunodeficiency, cystic fibrosis,congenital heart disease, and severe illnesses of
infancy
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RSV Immune Globulin passive immunization monthly intravenous infusions recommended for infants with documented BPD and
for those with a gestational age of less than 35weeks
Palivizumab monoclonal antibody can be given by intramuscular injection
administered monthly desirable for children in whom vascular access is a
challenge
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Admission visible moderate to severe respiratory distress
hypoxia
apneic spells
dehydration sustained tachypnea (RR >60 breaths/min)
considered in all infants with a history of BPD,congenital heart disease, and immunocompromise
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Discharge mild disease
taking fluids well
whose parents are capable
Parents should be instructed on how toperform aggressive nasal suctioning andevaluate respiratory distress
Decongestants and antihistamines are ofquestionable benefit