“Asthma” by Julia Pian and Laura Chiel for OPENPediatrics
25
August

By Adem Lewis / in , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , /


Asthma, by Julia Pian
and Dr. Laura Chiel. Learning objectives– by the
end of this video, the learner will understand the
pathophysiology, clinical presentation,
diagnosis, and management of
childhood asthma in the inpatient and
outpatient setting. Introduction– asthma is
one of the most common pediatric diseases with 1
in 10 pediatric patients in the United States
carrying the diagnosis. The disease commonly
manifests as wheezing– [WHEEZING SOUNDS] –breathlessness, chest
tightness, and coughing, and can cause significant
morbidity and mortality. Pathophysiology– the underlying
pathophysiology of asthma is reversible
airflow obstruction. There are three main mechanisms
that cause this obstruction– bronchoconstriction,
inflammation, and secretions. Bronchoconstriction occurs
through constriction of smooth muscles
around airways and is mediated through parasympathetic
muscarinic M3 receptors. Inflammation refers to airway
wall edema and inflammatory cell infiltration
in the submucosa, including eosinophils, activated
helper T-cells, mast cells, and sometimes neutrophils. Finally, increased
airway secretions can narrow the airway lumen. These secretions are made up
of mucus, desquamated lining cells, and intraluminal
eosinophils. Clinical presentation–
asthma generally presents at a young age
with approximately 80% of children with asthma
developing symptoms before age 5. Some common triggers of asthma
exacerbations in children include viral upper
respiratory infections, smoke, seasonal change, cold
weather, cockroaches, mold, and other environmental factors. The most common
symptoms of asthma are cough and wheezing
with breathlessness, chest tightness, chest pressure,
and chest pain also described. There are a number of
different features of cough that should raise
concern for asthma. These include nocturnal
cough, a cough that varies with the
seasons, a cough that lasts more than three weeks,
or a cough in response to specific exposures, such
as cold air or exercise. The cough of asthma is
usually dry and hacking, but may produce clear
or white sputum. The wheeze of asthma is produced
due to the narrowed airways and tends to be
heard on expiration. This wheeze can
sometimes be appreciated without a stethoscope. If the patient has a silent
chest an physical exam during an asthma
exacerbation, this may represent a dangerous
limitation of airflow and escalation of care
should be considered. Other important elements
of the history to include are symptom control, use
of a controller medication, known asthma triggers,
impact on participation in school and activities,
previous exacerbations including hospitalizations,
ICU admissions, or intubations, and a personal medical history
or a family history of atopy. Atopy is a hypersensitivity
to allergens and a common triad of atopic
diseases are asthma, eczema– also known as
atopic dermatitis– and allergic rhinitis. Diagnosis– when a child
presents with cough, wheezing, and breathlessness, the
differential diagnosis should include asthma,
bronchiolitis, foreign body in the airway, anaphylaxis,
and other causes of airway obstruction. Asthma is suspected to be the
most likely diagnosis based on history and physical exam. Spirometry can be performed
in the outpatient setting. Reversible airflow obstruction
with FEV1, less than 80% of expected, and reduced
FEV1 over FVC ratio can help confirm the
diagnosis of asthma. However, normal
pre-bronchodilator spirometry does not rule out asthma. Children under five years
of age are typically too young to perform spirometry. You may hear providers use
the term reactive airway disease for very young children
who have symptoms of asthma, but this label is
nonspecific and may lead to underdiagnosis of asthma. In children who are too
young to perform spirometry, improvement in symptoms with
the trial of bronchodilator may help establish
the diagnosis. A chest X-ray is not
required or recommended to make a diagnosis
of asthma, but it may be done to rule out other
conditions on the differential diagnosis. The chest X-ray in
asthma is often normal, but may show hyperinflation,
bronchial thickening, or atelectasis. Venous blood gas
samples may be obtained for patients with severe
asthma exacerbations. Because patients with asthma
exacerbations are tachypneic, CO2 values are
expected to be low. A normal CO2 may suggest that
the patient is not effectively ventilating and
that the patient is at risk for impending
respiratory failure. Management– the management
of asthma focuses on two main areas– pharmacologic therapy
and asthma education. As described
previously, asthma is a result of bronchoconstriction,
inflammation, and increased secretions. Each of the medications
used to treat asthma targets one of these mechanisms. Bronchoconstriction is
treated most commonly with albuterol, a
beta 2 agonist which leads to smooth muscle
relaxation around the airways. In more severe cases,
intravenous magnesium sulfate is also used to address
bronchoconstriction. Inflammation is addressed
with various forms of steroids depending on the situation. Some children use inhaled
corticosteroids daily. During an acute
exacerbation, a short course of IV or oral steroids is
given to achieve control. Finally, ipratropium can help
reduce secretions as well as bronchodilate. Of note, many medications
can be delivered via inhaler or via nebulizer. The mode of delivery is
determined based on patient age and availability. Outpatient management–
let’s discuss the outpatient treatment of asthma. Some patients with
asthma can be managed with an albuterol
inhaler as needed. Medication that is used only
when a patient is symptomatic is called a rescue medication. However, many asthma
patients require daily therapy to
control their symptoms, or a controller medication. A stepwise treatment letter
issued by the National Asthma Education and
Prevention Program is used to gradually
step up treatment based on symptom severity. Each category of
severity is determined by the number of days per week
that a patient experiences symptoms, the number
of nighttime awakenings that occur per week,
how often they need to use their short-acting
beta agonist, and how severely their
symptoms interfere with daytime activities. With each step in
severity, the patient will either increase the
dose of a current medication or add another medication
to the regimen. For example, if a patient
with mild intermittent asthma is found to be using the rescue
inhaler more than two days per week, categorizing them as
having mild persistent asthma, a daily low dose
inhaled corticosteroid would be prescribed in addition
to their short-acting beta agonist. If this same patient
worsens and is later categorized as having
moderate, persistent asthma, a daily long-acting beta
agonist such as salmeterol may be added to
their regimen along with their daily
inhaled corticosteroid and short-acting beta agonist. When children present to
the emergency department with an asthma
exacerbation, a scoring tool may be used to determine
severity and management follows accordingly. In moderate to severe
cases, patients are often given
albuterol and ipratropium to combat bronchoconstriction
and help reduce secretions. Sometimes they are given three
doses of nebulized albuterol and ipratropium back-to-back. You may hear providers refer
to three doses of albuterol and ipratropium given
back-to-back as a unineb, or a unified nebulizer. We recommend against using this
language as its meaning is not clear to all providers. The patient is also
given IV or oral steroids to help reduce inflammation. The albuterol treatments are
then spaced out over time based on clinical symptoms. In particular, a patient’s
work of breathing, oxygen saturation, respiratory
rate, respiratory exam, and dyspnea are used to help
determine whether treatments can be spaced out further. If a child remains symptomatic
despite frequent albuterol treatment, magnesium is
considered to further aid against bronchoconstriction. Hospitals use
institution-specific criteria based on the time interval
between albuterol treatments to determine whether
children can be discharged, should be admitted
to the general floor, or should be admitted to an ICU. Inpatient management– on
the general pediatrics floor, patients will continue
treatment with albuterol until they can reliably
space treatments far enough apart to allow safe
administration of treatment at home. They will also continue
on their home asthma controller medications and the
systemic steroid course started in the emergency department. Asthma education will be
conducted with the family and an asthma action
plan put in place before the patient
is discharged. Treatment for a patient
admitted to an ICU may include non-invasive
ventilation, terbutaline, and heliox. Intubation is avoided
unless absolutely necessary as intubation
and positive pressure ventilation is associated
with high mortality rate in children. The management of
asthma in the ICU is beyond the scope
of this video. Asthma education–
families should be counseled on the importance
of avoiding the patient’s asthma triggers such
as allergens, animal dander, fragrances, or smoke. They should be encouraged to
practice good hand hygiene and to obtain the flu
vaccine annually to prevent respiratory infections. The proper administration
of medication should be reviewed, including
how to use a metered dose inhaler and the importance
of using a spacer to effectively deliver
the inhaled medication to the airways and prevent the
development of oral thrush. The concepts of rescue
and controller medications should be reviewed. Every family should have an
asthma action plan, a document which details how to
care for the child’s asthma on typical days and on
days when the child is at risk for worsening asthma symptoms,
such as in the setting of a respiratory illness or
exposure to other triggers. In summary, asthma is the
most common pediatric disease in developed countries caused by
reversible airflow obstruction due to bronchoconstriction,
inflammation, and secretions. It is most commonly
clinically diagnosed in children before the age of 5
and presents as recurrent cough and wheezing. The mainstays of treatment are
short-acting beta agonists, such as albuterol, steroids,
and antimuscarinic agents such as ipratropium. As an inpatient,
patients are managed based on the frequency
of albuterol nebulizer treatments needed. As an outpatient,
patients are managed based on the severity
of the symptoms in a stepwise treatment ladder. Asthma education is
essential to help children achieve asthma control. Thank you for watching
this video on asthma.


2 thoughts on ““Asthma” by Julia Pian and Laura Chiel for OPENPediatrics

  1. Spirometry is hard to pull off correctly for children. Do you have any ideas on how to improve this? Or do you recommend other diagnostics?

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