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ANSWERS Board Review Quiz February

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					ANSWERS Board Review Quiz – February 2010

ALLERGY AND RELATED DISORDERS AND RESPIRATORY DISORDERS

1. Question 175 (2009)
ANSWER: D – oral candidiasis
Despite remaining the cornerstone therapy for persistent asthma, many parents are reluctant to
have their children begin using inhaled corticosteroids. Addressing parents' concerns and outlining
the potential adverse effects may improve understanding and compliance.

Local oropharyngeal symptoms, including dysphonia, oral candidiasis, and cough, are commonly
encountered adverse effects of inhaled corticosteroids. Local symptoms appear to be dose-related
and can be lessened by using a "spacer" and rinsing out the mouth after use. A number of studies
have documented a transient decrease in growth velocity during the first year of inhaled
corticosteroid therapy, but a daily cumulative dose up to 800 mcg of inhaled budesonide has been
shown not to affect predicted adult height.

Less common adverse effects of inhaled steroids include acne, mood swings, weight gain, decreased
serum immunoglobulin G concentrations, and rarely, posterior subcapsular cataracts and adrenal
suppression.

Inhaled steroids are used in persistent asthma to help halt lung remodeling by decreasing bronchial
inflammation, reducing inflammatory mediators, and decreasing bronchial hyperresponsiveness.

2. Question 114 (2009)
ANSWER: B – laryngomalacia
The infant described in the vignette has congenital stridor (noisy inspiratory breathing) and exhibits
only mild increased work of breathing when supine and when distressed. Although no immediate
intervention is required to maintain airway patency, the clinician examining the patient needs to
determine the cause of the stridor. Some have reported a characteristic coarseness of the stridor
when due to a supraglottic (laryngeal) disorder, a musical quality associated with glottic (vocal
cord) disorders, and more of an expiratory noise or prolonged expiratory phase with a wheeze in
subglottic disorders of airway obstruction (Item C114A).

The most common cause of congenital stridor is laryngomalacia, a congenital weakness, or
floppiness, in airway laryngeal cartilages (epiglottis, arytenoid cartilages, larynx) (Item C114B). A
cleft lip does not cause stridor. A tracheal hemangioma (Item C114C) may cause airway
obstruction, but usually this is associated with expiratory wheezing. Tracheomalacia may complicate
prolonged intubation and positive pressure ventilation in preterm infants and typically is associated
with expiratory wheezing or inspiratory cessation of airflow with airway collapse unless positive
distending pressure is applied (Item C114D). A vocal cord polyp is a rare congenital condition that
may be associated with human papillomavirus infection that can cause stridor, which would not be
expected to change with position.

3. Question 207 (2009)
ANSWER: E – vocal cord dysfunction
The teenager described in the vignette has signs and symptoms consistent with vocal cord
dysfunction (VCD), a condition that can mimic or coexist with asthma. In contrast to an asthma
exacerbation, the key features of VCD exhibited by this girl include a normal room air pulse
oximetry reading, failure to improve with her beta2 agonist inhaler, clear lungs, and difficulty with
inspiration instead of expiration. A blunted inspiratory loop on spirometry also is supportive of VCD,
although affected patients usually have normal spirometry readings when not experiencing
symptoms. Triggers for VCD can include viral upper respiratory tract infections, chemicals, fumes,
pollution, emotional changes, laughing, exercise, gastroesophageal reflux (GER), and cold air.

GER can cause cough and be a trigger for asthma. It may worsen during exercise, eating, or when
supine. Although GER is a cause of chronic cough, the patient in the vignette does not admit to GER
symptoms, making this diagnosis unlikely.

Postnasal drip syndrome, now termed upper airway cough syndrome, can result in coughing due to
allergic rhinitis, nonallergic rhinitis, or sinusitis. The lack of nasal congestion, rhinorrhea, or
postnasal drip for this girl makes this an unlikely cause of her acute symptoms.
Psychogenic cough, also called habit cough syndrome, is a well-described chronic cough that may
begin after a viral upper respiratory tract infection. The cough usually is nonproductive and does not
occur during sleep. Teenagers who have asthma may use coughing as a method to avoid school
(factitious or malingering), but the girl in the vignette is not having symptoms during a specific
class or time of day.

4. Question 111
ANSWER: B – most cases are preceded by an upper respiratory tract infection
Psychogenic cough, sometimes called habit-cough syndrome, is an uncommon cause of chronic
cough in children and adolescents. Many experts discourage using the label "psychogenic" because
underlying psychological or psychosomatic concerns are uncommon in affected children. Most cases
of psychogenic cough begin with an uncomplicated upper respiratory tract viral illness, but the
cough lingers for months to years. The classic triad of symptoms includes a repetitive cough,
cessation during sleep, and the characteristic hacking, barky cough, as described for the boy in the
vignette. Although most affected children undergo multiple therapeutic interventions and diagnostic
tests, the characteristic presentation may allow clinicians to avoid expensive or invasive tests to rule
out other causes.

Successful therapies for habit-cough include behavioral therapy, suggestion therapy, and self-
hypnosis. Once resolved, most cases of habit-cough do not recur. Unlike some cases of viral upper
respiratory tract infections, habit-cough resolution is not followed by recurrent wheezing.

5. Question 15 (2010)
ANSWER: E – her son’s symptoms are related to his allergic rhinitis
The boy described in the vignette is exhibiting a common form of food allergy called food pollen
syndrome or oral allergy syndrome (OAS). OAS is seen in 30% to 40% of children who have allergic
rhinitis. Certain foods contain proteins that are similar to airborne allergens, and patients who are
allergic to an aeroallergen are at risk of developing reactions to the cross-reacting food protein
(Item C15).

In most cases, symptoms are isolated to the oropharynx, where food comes in contact with a
mucosal surface, and include lip, tongue, and oral mucosal pruritus; tingling; and occasionally
angioedema. Interestingly, because these food proteins are heat-labile, cooking the food (eg, apple
pie) negates its antigenic properties. Although symptoms typically are mild, there are reports of
severe reactions. In one recent review involving 1,361 patients who had OAS, 8.7% experienced
systemic symptoms outside the gastrointestinal tract, 3% experienced symptoms other than oral
symptoms, and 1.7% experienced anaphylactic shock.

Because OAS is relatively specific to particular cross-reacting food(s), patients do not need to avoid
other fruits or vegetables to which they have not experienced reactions. Avoidance of unrelated
foods (eg, milk, eggs) is not recommended unless the history suggests a previous reaction. The
decision to avoid causative foods can be based on the severity of reaction. Referral to an allergist
typically is reserved for situations when skin testing is desired or if the child has experienced
systemic symptoms. Skin testing is performed using a commercial extract or the fresh fruit or
vegetable. When using fresh food, the sensitivity of skin testing with a history of reproducible
reactions is close to 90%, while the negative predictive value is more than 90%. The skin prick
device is pressed into the food and then pressed in the skin (so-called "prick-prick" skin test).

Other immunoglobulin (Ig) E food reactions include atopic dermatitis, eosinophilic esophagitis, and
specific food allergy. In the United States, 85% of specific food allergies are due to egg, milk,
wheat, soy, peanuts, tree nuts, fish, and shellfish. Most children who have IgE food allergies react
to only one or two causative foods, although children who have tree nut allergy, atopic dermatitis,
and eosinophilic esophagitis often have IgE-mediated reactions to multiple foods.

6. Question 31 (2010)
ANSWER: A – allergy skin testing
Clinicians should be aware that many unconventional and unproven testing methods are still
promoted for the diagnosis and management of allergic conditions. For example, applied kinesiology
theorizes that an allergen or irritant substance provokes weakness when the person ingests, holds,
or even stands in close proximity to the offending agent. To date, no conclusive evidence supports
this theory or test.
The cytotoxic test is an in vitro test involving microscopic evaluation of blood after placing a drop of
the offending agent (eg, food, mold) on a slide containing the patient's blood. Changes in the
appearance, size, shape, and integrity of leukocytes are interpreted as a "positive" response. A
thorough United States Food and Drug Administration review has concluded that the efficacy of the
cytotoxic test is unproven.

The pulse test evaluates whether an increase or decrease in pulse rate follows food ingestion,
injection, or sublingual application and is interpreted as an "allergy" if a change occurs.

Finally, provocation-neutralization is a nonstandardized test for food and inhalant allergies. A series
of dilutions of an allergen are injected in the upper arm until the patient reports subjective
sensations. A progressive series of lower concentrations subsequently are administered until the
sensation abates. The lower dose is used for injection treatment to build immunologic tolerance for
the offending trigger. Both the testing and treatment method are unproven and should be
considered similar to placebo therapy.

Finally, Candida immunotherapy or avoidance of yeast ingestion for patients diagnosed with yeast
or Candida hypersensitivity is unproven.

The parent in the vignette is concerned for mold allergy. Molds generally are believed to have three
effects: direct infection through ingestion or inhalation, release of toxins or irritants as mold
byproducts, and an immune response (eg, allergic bronchopulmonary aspergillosis, allergic fungal
sinusitis, allergic rhinitis, asthma). Significant water damage, leaking water sources, or visible mold
growth represent real health concerns. Commercial testing for mold can provide some information,
but quantifiable amounts are found in 80% of homes in the United States. Thus, the presence of
mold does not necessarily indicate causation. For example, Alternaria alternata is linked to fatal
asthma but is primarily an outdoor aeroallergen. Allergy skin prick testing or blood testing can aid in
detecting immunoglobulin E-mediated responses to molds and other allergens and is reasonable as
part of determining the cause of this adolescent's asthma exacerbations.

7. Question 63 (2010)
ANSWER: D – immediately administer 0.3 mg of self-injectable ephinephrine
The boy described in the vignette experienced an anaphylactic reaction, a potentially life-
threatening event. In children, the most commonly identified causes for anaphylaxis are food,
insects, drugs, latex, and vaccines. Food allergy is the most common cause of anaphylaxis in the
home or school setting and accounts for an estimated 50% of all pediatric cases annually. Some
85% to 90% of allergic reactions to food in children are due to milk, egg, soy, wheat, peanuts, tree
nuts, fish, and shellfish. Peanuts and tree nuts account for most cases of fatal anaphylaxis from
foods in the United States.

Recently, a panel of experts published a set of clinical criteria for diagnosing anaphylaxis (Item
C63).

The skin and respiratory system are the most commonly affected systems in cases of food allergy-
induced anaphylaxis, as described for the boy in the vignette. Fatal anaphylaxis almost always is
due to airway edema and subsequent respiratory failure.

For a person experiencing anaphylaxis, epinephrine should be administered immediately and
without delay. Observation of the child while calling his parents wastes precious time in this
situation. In the school setting, self-injectable intramuscular epinephrine is used. Other methods of
delivery, used primarily in the hospital setting, include intravenous, intraosseous, and via an
endotracheal tube. Current epinephrine injectors are available in two strengths: 0.15 mg and 0.30
mg. The child in the vignette, who weighs more than 30 kg, should be given the 0.30-mg dose,
preferably in the lateral thigh. Antihistamines may decrease pruritus or flushing, but their effect has
a slow onset, and they are not recommended as the initial treatment for anaphylaxis. Because some
children may require additional doses of epinephrine and observation, emergency services should be
called, but waiting for them to arrive to make a decision regarding the initial dose of epinephrine is
not recommended.

Caregivers of children who have experienced food-induced anaphylaxis should have epinephrine
readily available, understand the indications for its use, have a written action plan, and understand
the proper technique for use of self-injectable epinephrine devices.

8. Question 143 (2010)
ANSWER: E - symptoms can start within 5 minutes of exercise, but peak symptoms
usually occur after the exercise is stopped
Exercised-induced asthma (EIA) results in a transient narrowing of the airway following vigorous
exercise and is associated with a 10% to 15% decrease in the forced expiratory volume in 1 second
(FEV1). A number of mechanisms are postulated for EIA, but the most accepted one is based on the
decreased warming and humidification of inhaled air during exercise. Upon completion of exercise,
there is a marked influx of fluid due to rapid rewarming, which results in mucus production and
airway narrowing. Because temperature change is a key aspect of EIA, exercise or sports in cold
weather provokes EIA more readily than in warmer weather. Also, a slow warm-up, particularly in
cold weather, results in a more gradual change in airway temperature and can lessen EIA
symptoms.

EIA symptoms such as cough, shortness of breath, and wheezing may begin during exercise but
classically peak 5 to 10 minutes after completion of exercise. The more strenuous the exercise, the
more intense the asthma attack. For example, running produces more severe airflow limitation than
jogging, which, in turn, produces more limitation that walking. Short, intense bouts of work lasting
fewer than 2 minutes produce fewer problems than longer periods of effort because of the
shortened time of airway cooling. EIA symptoms usually resolve spontaneously after 30 minutes of
rest.

Exercise is a very common asthma trigger for children, with 70% to 90% of children who have
asthma demonstrating EIA symptoms. Pretreatment with a short-acting beta2 agonist is appropriate
for isolated EIA. Because most patients who have EIA will be identified with persistent asthma, the
latest Global Initiative for Asthma guidelines, published in late 2008, continue to recommend
treatment with inhaled corticosteroids to control any underlying persistent asthma. Finally, acute
episodes can be attenuated by having the athlete warm up before strenuous exercise.

Clinically, exercise challenges usually are performed if the diagnosis of EIA is in doubt or if the
patient is not responding appropriately to usual EIA therapies such as beta2 agonists, inhaled
corticosteroids, or leukotriene antagonists. Prior to exercise, two baseline spirometry measurements
are performed. Ideally, the FEV1 measurements should not differ by more than 3%. The patient
then exercises, preferably for the same duration and in the same conditions (eg, running outside on
a cold day) that have provoked symptoms previously. Postexercise spirometry is performed at 5,
10, 15, and 30 minutes after exercise. During this challenge, a decrease of 15% in FEV1 is
considered consistent with EIA. Other protocols available in a monitored setting include eucapnic
voluntary hyperpnea, hypertonic saline challenge, and inhaled powder mannitol challenge. These
require a 10% drop in FEV1 to be consistent with EIA.

Other conditions that may result in poor exercise performance include vocal cord dysfunction, poor
physical conditioning (ie, overweight, out of shape), gastrointestinal reflux, poor cardiac function,
and restrictive lung disease.

9. Question 175 (2010)
ANSWER: B – formoterol
Exercise-induced asthma (EIA) is not only a problem for children and adolescents who have
underlying persistent asthma but also can affect 10% to 50% of elite athletes. In addition to
ensuring control for underlying persistent asthma, a warm-up period prior to maximal exertion as
well as administration of an inhaled beta2 agonist are recommended to prevent EIA. Short-acting
beta2 agonists, such as albuterol or levalbuterol, are the most common bronchodilators used.
Typically administered 20 minutes prior to activity, short-acting beta2 agonists provide 2 to 4 hours
of bronchodilation. However, such treatment may not be effective when anticipated activity is
longer, such as the 8 to 12 hours described for the boy in the vignette. Long-acting beta2 agonists
that are approved for prevention of EIA in children older than 4 and 5 years of age include
salmeterol and formoterol, respectively. However, these agents should not be used as monotherapy
for persistent asthma. Formoterol has a faster onset of action than salmeterol (10 minutes versus
30 minutes to reach an increase of 15% in forced expiratory volume in 1 second, and is appropriate
for the boy in the vignette.
In December 2008, the Pulmonary-Allergy Drugs Advisory Committee recommended that the United
States Food and Drug Administration (FDA) consider a ban on the use of both salmeterol and
formoterol in children and adolescents. However, the Committee focused on the use of long-acting
beta2 agonists for persistent asthma, citing a meta-analysis in adults showing increased risk for
asthma-related hospitalization, asthma-related intubation, and asthma-related deaths. At the time
of this writing (March 2009), the FDA has not rendered a decision on this issue.

Leukotriene receptor antagonists (LTRAs) such as montelukast can be used for EIA. Studies have
demonstrated that LTRAs reduce the immediate and late phase of exercise bronchoconstriction.
Interestingly, the response to LTRAs varies from poor to excellent. Pharmacogenetic studies are
ongoing to determine which patient group exhibits the best response. Anticholinergic inhalers such
as ipratropium are not recommended for the treatment of EIA.

10. Question 191 (2010)
ANSWER: D - this patient should be tested to all flying hymenoptera (ie, wasps, hornets,
bees, yellow jackets)
The boy described in the vignette experienced a near-fatal reaction to a flying insect, with signs and
symptoms consistent with anaphylaxis. In the United States, stinging insects causing
immunoglobulin (Ig) E-mediated reactions include honeybees, yellow jackets, yellow hornets, white-
faced hornets, paper wasps, and fire ants. The identification of an IgE-mediated allergic disorder
involves identifying the allergen, estabishing a causal relationship between the allergen and the
reaction, and demonstrating the presence of specific IgE via immediate type skin testing or in vitro
testing.

Indications for immediate type skin testing include:

1. Identification of aeroallergen triggers in patients who have asthma
2. Allergic rhinitis that is not controlled with usual medications or if specific avoidance (eg, pet
dander) is desired
3. Food allergy
4. Insect sting allergy
5. Vaccine, drug, or latex allergy
6. Evaluation for moderate-to-severe atopic dermatitis
7. Other conditions, including allergic fungal sinusitis, allergic bronchopulmonary aspergillosis, and
eosinophilic esophagitis

The decision to perform skin or in vitro testing depends on the age of the patient, the desire to start
allergen immunotherapy, time since the reaction, and severity of the reaction.

Allergy skin testing can be performed at any age, but infants and toddlers generally do not tolerate
intradermal skin testing well and may not be able to communicate to their parent/clinician if they
are developing a reaction during testing. In addition, clinicians may elect to start with in vitro
testing in patients who have experienced life-threating reactions, as described in the vignette.
Unfortunately, both skin testing and in vitro testing, when used alone for assessment of insect sting
allergy, may provide false-negative results in up to 25% of patients. In cases of anaphylaxis, if the
results of the initial test (skin or in vitro) are negative, the second testing modality should be
undertaken. If testing is performed too soon (ie, within 2 weeks of the reaction), results may be
negative due to depletion of mast cell mediators. Generally, skin testing should be performed 4 to 6
weeks after a sting reaction.

Current guidelines recommend that patients who experience less severe reactions (eg, local or
normal reactions, large local reactions, or cutaneous-only symptoms in children younger than than
16 years of age) do not require testing because of their low risk for future anaphylaxis.
Epidemiologic studies have demonstrated that 25% to 50% of individuals can develop specific IgE to
stinging insects, even after a normal or local reaction. However, such individuals (local reaction
only) should not be tested, based on their normal reactions, and no specific avoidance measures or
immunotherapy are recommended.

Finally, when flying insect testing is performed, a complete set of the five Hymenoptera venoms
(honey bee, yellow jacket, white-faced hornet, yellow hornet, wasp) should be used unless the
specific insect is captured and identified by an entomologist.
11. Question 207 (2010)
ANSWER: A - a high-dose inhaled steroid and long-acting beta agonist
Based on the 2007 National Asthma Education and Prevention Program Expert Panel Report 3
Guidelines for the Diagnosis and Management of Asthma, the 12-year-old girl described in the
vignette has severe persistent asthma. A stepwise approach is used to identify the severity of
asthma in a new patient and determine the level of control. This stepwise approach accounts for
patient's treatment responses and changes that often occur over time. The choice and schedule of
medications is determined by the level of asthma severity and asthma control. Severe persistent
asthma in children 12 years of age or older requires the initiation of step 4 or step 5 therapy (Item
C207).

The preferred treatment includes a medium- to high-dose inhaled corticosteroid plus a long-acting
beta agonist (LABA). Omalizumab is an additional therapy that could be considered for this girl if
she had allergic asthma, with evidence of specific sensitization to associated allergens and an
appropriate total serum immunoglobulin E concentration.

A medium-dose inhaled corticosteroid plus an oral leukotriene antagonist is an alternative to the
previously noted regimen but is not the first choice. An oral leukotriene antagonist or oral
theophylline as monotherapy are only appropriate for step 2 therapy.

In asthma, exposure to allergens leads to an early airway response that develops fully within 10 to
20 minutes. In addition, a late airway response can occur and develop fully 3 to 8 hours after
exposure. Oral and inhaled glucocorticoids inhibit the late-phase reaction but not the early-phase
reaction. Inhaled short-acting and long-acting beta-adrenergic agents are potent inhibitors of the
early-phase reaction. Leukotriene receptor antagonists (montelukast, zafirlukast) and leukotriene
synthesis inhibitors (zileuton) also block the early-phase response and may have a mild impact on
the late-phase response.

12. Question 223 (2010)
ANSWER: B – intermittent
The 2007 National Asthma Education and Prevention Program Expert Panel Report 3 for the
Diagnosis and Management of Asthma (ERP3) continues to provide a framework for the
determination of asthma severity and the initiation of appropriate therapy. EPR3 advises
assessment of baseline asthma severity when initiating therapy, then monitoring asthma control
while adjusting stepwise therapy to prevent functional impairment and minimize the risk of an
exacerbation (Item C223).

The new guidelines separate children into three groups: 0 through 4 years, 5 through 11 years, and
12 years and older. Based on an assessment of the impairment and risk, the severity of asthma
experienced by the 12-year-old boy described in the vignette is categorized as intermittent. The
nomenclature has changed from mild intermittent to intermittent as clinicians need to recognize
that intermittent symptoms may be mild, moderate, or severe. Characteristics of intermittent
asthma, as seen in the child in the vignette, include normal pulmonary function test results,
daytime symptoms fewer than 2 days per week, and nighttime symptoms fewer than 2 days per
month. Step 1 therapy for intermittent asthma involves using an as-needed short-acting
bronchodilator. Once a child is diagnosed with asthma, the frequency of follow-up can be based on
asthma severity and level of control.

Exercise is a common trigger of asthma for children. Approximately 70% to 90% of children who
have asthma are believed to have symptoms of exercise-induced asthma (EIA). Although the child
in the vignette may have exercise-induced symptoms, a classification of EIA is less accurate than
intermittent asthma because the child has symptoms outside of exercise (ie, at night). Because up
to 40% of children who have allergic rhinitis have some degree of asthma and 60% to 80% of
children who have asthma have allergic rhinitis, asking about other atopic diseases is
recommended.

13. Question 254 (2010)
ANSWER: B - epinephrine reaches higher peak plasma concentrations if injected into the
thigh rather than the arm
The prevalence of food allergies has continued to increase over the past 3 to 4 decades. Specifically,
many children, parents, and school officials have been faced with the need to know about and
understand how to recognize and appropriately treat food anaphylaxis in the school. Education and
counseling of school officials and health-care clinicians is paramount to reduce morbidity and
mortality from food anaphylaxis.

The most common antigenic triggers of anaphylaxis are foods, drugs, insect venom, radiocontrast
media, and latex. After exposure to an antigenic trigger, symptoms generally develop within 5 to 30
minutes, although symptoms can occur up to several hours after the exposure. Severe allergic
reactions usually occur after binding of specific immunoglobulin (Ig) E to the high-affinity IgE
receptor, with subsequent cross-linking of receptors and mediator release (eg, histamine, tryptase)
from mast cells and basophils.

Cutaneous manifestations such as urticaria, flushing, pruritus, and angioedema are the most
common symptoms in anaphylaxis, occurring in 80% to 90% of episodes. Respiratory symptoms
such as dyspnea, wheezing, shortness of breath, and cough are the next most frequent symptoms.
Cardiovascular symptoms include cardiovascular collapse, tachycardia or relative bradycardia, and
arrhythmias. Among the gastrointestinal manifestations are nausea, vomiting, diarrhea, abdominal
pain, and cramping. Finally, many patients complain of either a metallic taste or "a sense of
impending doom."

Appropriate treatment of anaphylaxis consists of early administration of epinephrine. Because
anaphylaxis can occur in the absence of a health-care professional such as at school, home, or a
birthday party, children at risk always should have self-injectable epinephrine nearby. Although
parents or other adults may be reluctant to inject a child with epinephrine, this agent, not an
antihistamine, is the drug of choice for anaphylaxis. In the past, outpatient administration of
epinephrine was subcutaneous, but research has demonstrated that intramuscular injection,
specifically in the thigh, is the preferred route and location due to higher and faster peak plasma
concentration. If epinephrine is administered, parents or school personnel should follow an
emergency action plan. This should involve calling emergency services to evaluate the child and
transport him or her to the emergency department for further evaluation. The effects of a single
dose of epinephrine typically last for 5 to 15 minutes; up to 20% of individuals experiencing
anaphylaxis may require a second epinephrine dose. When symptoms persist, a second (or third)
dose should be administered, even if the parent or school professional still is awaiting the
ambulance. Although epinephrine always is the drug of choice in anaphylaxis, glucagon may be
required in refractory cases for patients using beta blockers.

Self-injectable epinephrine should be available for all locations (ie, the patient usually carries one to
two injectors), but leaving the device in the car is not recommended because extreme temperature
changes can decrease the efficacy. Recommended storage temperatures are 20° to 25°C at home
and 15°to 30°C during trips outside the home, school, or workplace.

Approximately 5% to 20% of patients who suffer initial anaphylactic events can experience a "late-
phase" response 4 to 24 hours later in which symptoms such as flushing, pruritus, or airway
obstruction recur. Such later symptoms result from the recruitment of inflammatory cells after the
initial hypersensitivity response.

14. Question 57 (2010)
ANSWER: A – aspiration pneumonia
The care of the technology-dependent child represents a considerable challenge for families and
clinicians. The exact number of such children is unknown, but recent estimates suggest that they
represent up to 20% of patient discharges from tertiary children's hospitals.

Anatomic abnormalities, impaired neurologic status, loss of normal oromotor coordination,
gastroesophageal reflux, and the presence of devices such as nasoenteric tubes and tracheostomies
can lead to recurrent aspiration of gastric or upper airway secretions among such children.
Aspiration can lead to a variety of respiratory problems, including wheezing, coughing, apnea,
laryngospasm, and recurrent pneumonias.

Tracheostomy tubes, even cuffed tubes, do not prevent aspiration and, in fact, may increase the
risk in some patients due to desensitization of the larynx and loss of protective reflexes in
combination with uncoordinated laryngeal closure. The child described in the vignette has a history
of coughing with feedings and now has signs of an acute respiratory infection that include fever,
tachypnea, and increased respiratory rate. Her chest radiograph demonstrates a diffuse right upper
lobe infiltrate in a location consistent with aspiration pneumonia and no evidence of a pneumothorax
(Item C57A)

Congenital lobar emphysemas typically present with respiratory distress by 6 months of age.
Radiographic findings include hyperinflation of the affected lobe with resultant atelectasis of
adjacent lobes and shifting of the mediastinum away from the lesion (Item C57B). Chest
radiography in viral infection typically shows hyperinflation with bilateral interstitial infiltrates and
peribronchial cuffing, and pulmonary hemorrhage is characterized by diffuse consolidation with a
"ground glass" appearance.

15. Question 89 (2010)
ANSWER: A – elevated level of carboxyhemoglobin
Pulse oximetry has gained widespread acceptance, often is considered the "fifth vital sign," and has
proven extremely useful in recognizing hypoxemia and decreasing critical airway events. Pulse
oximetry uses red and infrared light to measure the level of oxygenated and deoxygenated
hemoglobin. The amplitudes of the light signals are measured and mathematically calculated to
express the percentage of oxygen saturation.

Despite its enormous value, pulse oximetry has not been demonstrated to reduce mortality and has
several key limitations. First, it does not measure ventilation and may falsely reassure clinicians
about the adequacy of the patient's overall respiratory status. In addition, pulse oximetry can yield
falsely low saturations in critically ill patients who have vasoconstriction, poor perfusion,
hypothermia, or arrhythmias. Inaccurate readings also may result from ambient light interference or
patient movement, inability to discriminate values below 70% accurately, interference by venous
pulsations with tricuspid regurgitation, and the presence of abnormal hemoglobin such as
carboxyhemoglobin and methemoglobin. Arterial blood gases with co-oximetry measurements
should be obtained when the pulse oximetry reading does not correlate with clinical findings.

The child described in the vignette does not demonstrate any evidence of shock or impaired cardiac
performance. She has been rescued from a house fire and, therefore, is at high risk of carbon
monoxide poisoning. Pulse oximetry cannot distinguish carboxyhemoglobin from oxyhemoglobin,
resulting in a falsely high reading. Methemoglobinemia usually is caused by drug exposure or
congenital enzymatic defects. Because methemoglobin is read as both oxyhemoglobin and
deoxyhemoglobin by pulse oximeters, the saturation reading is generally around 85%. Fetal
hemoglobin has little effect on the accuracy of pulse oximetry. In addition, the child in the vignette
is 1 year of age and would be expected to have a trivial concentration of fetal hemoglobin. Finally,
pulse oximetry does discriminate values greater than 90% accurately, but at higher values (≥95%),
large fluctuations in PaO2 can occur with only small changes in oxygen saturation.

16. Question 98 (2010)
ANSWER: B – apnea of prematurity
Central apnea represents a total cessation of respirations and is mediated through mechanisms that
affect the neural integration of sensory input (stretch receptors, chemoreceptors, and
baroreceptors) and the central nervous system's efferent signaling for inspiration. By definition,
such cessations of respiration last 20 seconds or longer or if they are less than 20 seconds in
duration, are associated with cyanosis or bradycardia. The newborn described in the vignette
displays central apnea with cyanosis and bradycardia. Apnea of prematurity, a form of central
apnea, is considered a diagnosis of exclusion, and other potential contributing factors must be ruled
out. It is treated effectively and safely with the methylxanthine caffeine.

Central apnea is a common respiratory disorder among very low-birthweight preterm infants,
typically appearing in the first 2 weeks of postnatal life. It must be evaluated within the context of
the individual newborn's medical history and clinical setting. In addition, it must be distinguished
from obstructive apnea, which is often due to neck flexion with positioning; gastroesophageal reflux
with reflex glottic closure and cessation of airflow; and mechanical obstruction of the trachea or
larynx. Numerous conditions may lead to central apnea:


        Sepsis, meningitis, or necrotizing enterocolitis
        Prolonged hypoxemia (lung disease, patent ductus arteriosus, profound anemia)
        Central nervous system depressant effects of certain medications (opioids, barbiturates, and
         benzodiazepines)
       Intracranial hemorrhage (including intraventricular, subdural, or subarachnoid hemorrhage)
       Hydrocephalus (including posthemorrhagic hydrocephalus)
       Electrolyte abnormalities
       Hypoglycemia
       Temperature instability (hypothermia or hyperthermia)
       Prematurity and immature respiratory drive



Anemia of prematurity may contribute to apnea when it is profound (hemoglobin characteristically
<7 g/dL [70 g/L]), but this is a late phenomenon (occurring after 2 to 4 weeks of postnatal age).
Because the infant is receiving intravenous alimentation and some enteral feeding, it is unlikely that
he is experiencing hypoglycemia. Necrotizing enterocolitis is very uncommon in the first 3 days after
birth, and its association with apnea characteristically is in the context of a systemic illness,
presenting with shock and lethargy. Sepsis may cause apnea, but the newborn described in the
vignette does not exhibit any other clinical signs of sepsis.

17. Question 116 (2010)
ANSWER: D – foreign body aspiration
Cough and wheezing are common presentations in small children and infants. Although the most
common causes involve asthma and bronchiolitis, tracheal and esophageal foreign bodies may
present with the acute or subacute onset of cough and wheezing, especially in the older infant and
toddler. The age, lack of symptoms since age 3 months, and abrupt onset of symptoms after eating
a food that could be aspirated, as described for the boy in the vignette, suggest foreign body
aspiration rather than the other more indolent causes.

Contrary to popular belief, the aspiration of a small foreign body, including food (such as seeds or
nuts) is as common in the left as the right mainstem bronchus in young children because the
bifurcation of the trachea remains symmetric until the aortic knob grows larger in later childhood.
Typically, a chest radiograph may not disclose air trapping for up to 1 day after the aspiration,
despite the initial coughing. A careful history must be obtained for all children who have abrupt
onset of cough and wheezing, and children whose histories strongly suggest foreign body aspiration
should undergo prompt rigid bronchoscopy (Item C116). The child in respiratory distress should not
be sent to the radiology department but should have expiratory and inspiratory anteroposterior
chest radiography performed in the emergency department. Children who have aspirated foreign
bodies are at high risk for developing secondary bacterial pneumonia.

An esophageal foreign body, most often a coin, also may cause wheezing, but commonly patients
also have vomiting or an inability to tolerate solid foods. When the foreign body remains in the
upper half of the esophagus, the trachea may be compressed directly in some children, especially
infants.

Although bacterial pneumonia occasionally presents with wheezing (especially in the child who has
asthma) and wheezing may be seen with community-acquired pneumonia caused by Mycoplasma
and Chlamydia pneumoniae, other findings, such as fever, and bilateral signs upon auscultation of
the chest, often are present. Cystic fibrosis should be considered in children who have persistent
pulmonary disease, especially in conjunction with failure to thrive or diarrhea.

18. Question 132 (2010)
ANSWER: D – may be efficacious in monitoring preterm infants who have hypoxia due to
apnea of prematurity
Although many parents believe that the use of an infant cardiorespiratory monitor in the home after
an acute life-threatening event (ALTE) may be lifesaving, there is no evidence to support this belief.
However, there is some evidence supporting the use of home apnea monitoring for an infant who
has apnea of prematurity accompanied by hypoxia that responds to stimulation when the parents
are trained to respond appropriately to emergencies. Monitoring is continued until 2 to 3 months
have passed without an apneic episode.

Skills of communication and professionalism are very important in assisting parents and other
health-care professionals in understanding the use of evidence-based medicine to assign benefit and
risk determinations to specific diagnostic and management strategies. In particular, the use of a
home apnea monitor for an infant not proven to have a risk of recurrent paroxysmal
cardiorespiratory event may increase the possibility of harms such as vulnerable child syndrome,
parental anxiety and depression, and unnecessary administration of cardiopulmonary or other
resuscitative efforts because false alarms and instrument malfunction are far more common than
reversible infant cardiorespiratory events.

There is no evidence that using a home apnea monitor reduces the risk of sudden infant death
syndrome (SIDS) for a child who has apnea of prematurity, prior ALTE, or a sibling who suffered
SIDS. Home monitoring will not prevent future episodes of ALTE in the child who has
gastroesophageal reflux. Available evidence has failed to demonstrate a conclusive association
between gastroesophageal reflux and ALTE.

19. Question 137 (2010)
ANSWER: D – cystic fibrosis
The child described in the vignette was admitted to the pediatric intensive care unit for bronchiolitis,
but her history of failure to thrive and malabsorption as well as cystic lesions on radiologic imaging
are consistent with cystic fibrosis. Cystic fibrosis can have a variety of presentations, including
failure to thrive, delayed passage of stool, abnormal stools, rectal prolapse, and electrolyte
abnormalities, but acute or chronic respiratory symptoms account for more than 50% of all
presentations. Cough frequently is the first respiratory symptom, but progression to wheezing,
shortness of breath, and recurrent pneumonia is common. Infants younger than 1 year of age can
have bronchiolitis with wheezing, as described for the child in the vignette. Radiographic findings
include hyperinflation, bronchial thickening, and patchy atelectasis. Progressive disease is evidenced
by cyst formation, bronchiectasis, and lobar atelectasis. Severe complications of pulmonary disease
that may be life-threatening can include development of pneumothoraces, cor pulmonale, and
hemoptysis.

Congenital disorders of the lung such as congenital cystic adenomatoid malformation, congenital
lobar emphysema (Item C137), or pulmonary sequestration may present as respiratory distress
during infancy, but they generally are not associated with malabsorption or failure to thrive.
Clostridium difficile infection, which usually develops following antibiotic usage, can cause foul-
smelling diarrhea, but failure to thrive is not a characteristic finding.

20. Question 140 (2010)
ANSWER: B – endotracheally intubate the child
The sudden deterioration and development of toxicity 5 days after the onset of an apparent
crouplike illness described for the boy in the vignette is most consistent with development of
bacterial tracheitis. The stridor, retractions, and decreased oxygen saturation all are consistent with
this diagnosis. The rapidity of symptom progression and potential for increased purulent secretions
to obstruct the airway mandate early endotracheal intubation to maintain and clear the airway.
Parenteral antibiotic therapy, including coverage for Staphylococcus aureus, is another appropriate
component of treatment. Of note, bacterial tracheitis is a potential complication of measles
infection. A prolonged period of intubation may be necessary until the secretions clear with
antimicrobial therapy.

Although dexamethasone may be indicated for treatment of viral croup, the duration of illness and
acute deterioration described for this boy argue for an alternative diagnosis. A lateral neck
radiograph and pulmonary function testing are not helpful in the diagnosis of bacterial tracheitis and
might be dangerous in a potentially critically ill patient by delaying antibiotic therapy and airway
control. An emergency tracheostomy is not indicated if endotracheal intubation can be accomplished
successfully. However, a tracheostomy may be necessary and possibly lifesaving in the presence of
a fixed obstruction in the upper airway, such as epiglottitis, to bypass the lesion. Epiglottitis
typically presents acutely, with rapid progression over hours from onset of symptoms to toxicity and
impending airway obstruction. Fortunately, the advent of the conjugate Haemophilus influenzae
type b vaccine has made acute epiglottis an extremely rare entity.

21. Question 201 (2010)
ANSWER: C - emergent otolaryngology and anesthesia consultation
Epiglottitis is a medical emergency. The incidence of this disease has significantly decreased since
the introduction of the Haemophilus influenzae type b vaccine, and the most common infectious
pathogens now are Streptococcus pneumoniae, group A beta-hemolytic Streptococcus, and
Staphylococcus aureus. Often, the infection involves the entire supraglottic area, not just the
epiglottis, and is called supraglottitis. The current incidence in children younger than 5 years of age
is approximately 1.3 cases per 100,000, a decrease from the 40 cases per 100,000 seen 20 years
ago. Affected patients, typically between 2 and 8 years of age, usually present with the rapid onset
of fever, sore throat, and the "four Ds" (drooling, dysphagia, dysphonia, and dyspnea), as described
for the boy in the vignette. Patients may assume a position of comfort by sitting upright, leaning
forward, and bracing themselves with their arms, known as the "tripod position." Clinicians must be
vigilant for atypical presentations, especially among children younger than 2 years of age.

Airway management for this disease is paramount. Direct examination of the airway under
anesthesia (with the availability of personnel who can perform a tracheostomy if needed) is the
preferred management for suspected cases that involve signs of respiratory compromise (Item
C201A). Therefore, an emergent otolaryngology and anesthesia consultation is the most appropriate
next step for the boy in the vignette. An endotracheal tube that is 0.5 to 1 mm smaller than usual
for age generally is needed. Cultures of the supraglottic area can be obtained at the time of
intubation and broad-spectrum antibiotics effective against beta-lactamase-producing organisms
can be initiated. Lateral radiographs are diagnostic (Item C201B), as in this case, but should be
deferred in children strongly suspected of having epiglottitis until the proper personnel and
equipment are available to secure the airway if needed.

Invasive procedures, including phlebotomy, obtaining vascular access or a throat culture, or
intramuscular administration of medications, should be deferred until the airway is secured
properly. In addition, neither penicillin nor dexamethasone is indicated for the initial treatment of
epiglottitis.

22. Question 227 (2010)
ANSWER: E – sweat test
Cystic fibrosis is an autosomal recessive disorder characterized primarily by chronic pulmonary
disease and pancreatic insufficiency. A defect in chromosome 7 causes abnormal regulation of the
cystic fibrosis transmembrane conductance regulator (CFTR), which transports chloride in luminal
areas such as airways, intestines, sweat ducts, and pancreatic ducts. Fluid secretions become
thickened, leading to multisystem mucus plugging. Varying degrees of clinical features may be seen
because of the many mutations that can occur in the CFTR gene. The clinical features that can be
present include recurrent upper and lower respiratory tract infections (especially due to
Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae), steatorrhea (from
fat malabsorption) and meconium ileus, cholelithiasis, and male infertility. Deficiencies of vitamins
A, D, E, and K are present because of fat malabsorption. Failure to thrive is a common presenting
feature because of chronic malabsorption and frequent infections. Laboratory testing may reveal
hypoproteinemia, anemia, and hypochloremic metabolic alkalosis. Because the boy described in the
vignette has features that are most consistent with cystic fibrosis, a sweat chloride determination
(sweat test) is the most appropriate test to make the diagnosis.

A sweat test involves the application of pilocarpine to the skin to stimulate sweat production,
followed by measurement of the chloride concentration in the sweat. A positive result is greater
than 60 mEq/L. False-positive results may be seen in Addison disease, hypothyroidism, and some
glycogen storage diseases. False-negative results may be seen if the infant is malnourished or if
inadequate sweat volume is obtained, as in the neonatal period or with technical errors. Treatment
of cystic fibrosis includes the administration of pancreatic enzymes, increased caloric intake
(especially from fat), intensive antibiotic therapy for respiratory infections, and aggressive airway
clearance regimens. Inhaled antibiotics, such as tobramycin, used every other month have been
shown to reduce the incidence of pulmonary infections.

Giardia infections are caused by a protozoan that can be transmitted by the ingestion of cysts from
contaminated water. Clinical features include watery diarrhea, abdominal pain, and bloating.
Steatorrhea and respiratory symptoms are not seen. The diagnosis may be made either by viewing
the cysts in the stool or by immunosorbent assay. Antigliadin antibodies are helpful in making the
diagnosis of celiac disease, which causes chronic diarrhea and failure to thrive after the introduction
of gluten to the diet. Alpha-1-antitrypsin concentrations may be elevated in the stool if a protein-
losing enteropathy is present. This may be seen in cystic fibrosis, as well as other diseases such as
allergic gastroenteropathy and inflammatory bowel disease, but the finding is not diagnostic of
cystic fibrosis. Stool should be evaluated for ova, cysts, and parasites if infections such as
cryptosporidiosis are suspected.
23. Question 229 (2010)
ANSWER: A – barium swallow
A number of clinical entities are responsible for stridor in children, but when stridor accompanies
feeding, as described for the infant in the vignette, vascular ring is an important potential cause.
Vascular rings occur when the vascular structures of the aorta and pulmonary artery completely
encircle the trachea and the esophagus (Item C229A). Virtually every vascular ring can lead to a
similar set of clinical findings. For most affected patients, the intracardiac anatomy, physiology, and
hemodynamics are normal. When symptoms do occur, they typically result from compression of the
trachea or the esophagus. The most common symptoms related to tracheal compression are stridor,
wheezing, and dyspnea, all of which may be exacerbated by feeding. The age of onset and type of
symptoms depend on the anatomic type and severity of the vascular ring. If the anomaly is
unrecognized, patients may have recurrent pneumonia and progressive difficulty with feeding.

Radiography of the chest may be helpful and often can identify the sidedness of the aortic arch,
which is defined by the mainstem bronchus that it crosses. However, barium swallow is the most
useful study (Item C229B). When a vascular ring is suspected, both the posterior-anterior and
lateral views should be obtained, and fluoroscopy should be considered.

Computed tomography scan can be a useful diagnostic study for the patient who has stridor and a
vascular ring, but it exposes the young patient to a much higher amount of ionizing radiation than
does barium swallow (Item C229C). Because most patients who have vascular rings have normal
intracardiac anatomy, electrocardiography is not helpful in determining the cause of the stridor.
Radiography of the neck and the sweat test are not diagnostic for a vascular ring.

24. Question 233 (2010)
ANSWER: B - bronchoscopy may be useful for both diagnosis and treatment

Bacterial pneumonia is a significant cause of morbidity and mortality worldwide, especially in
developing countries. Most cases of pneumonia in the United States are treated on an outpatient
basis. The incidence of complicated pneumonias has increased, due in part to the increasing
prevalence of both antibiotic-resistant and more invasive pathogens. Complications of pneumonia
include pleural effusions, empyema, lung abscess, necrotizing pneumonia, pericarditis,
pneumothoraces, bronchopleural fistulas, and hematogenous spread to other sites.

Bronchopleural fistulas, the development of a connection between the bronchial tree and pleural
space, are rare but are associated with a high rate of morbidity and mortality (rates of 30% to 70%
have been reported). Most commonly, they follow a pulmonary resection, but they can occur with
necrotizing bacterial pneumonia or as a result of persistent pneumothoraces. Bronchopulmonary
fistulas generally are recognized in the intensive care unit patient by the presence of a persistent air
leak, as described for the boy in the vignette. Such fistulas rarely heal without intervention, and
they often prove difficult to manage. Frequently the diagnosis is clinical, but they are localized
definitively with bronchoscopy. Chest computed tomography scan has shown promise in both
diagnosing and planning surgical correction of complicated cases. Management strategies include
insertion or continuation of chest tubes, decreasing mechanical ventilator support to the lowest
pressures needed to allow spontaneous healing, differential lung ventilation, application of sealants
through a bronchoscope, and surgical closure. Surgical success rates of 80% to 95% rate have been
reported in adults, depending on the cause.

25. Question 249 (2010)
ANSWER: C – computed tomography scan of the chest
Congenital malformations of the lung usually present during the first 6 postnatal months, but
symptoms can be identical to more common pediatric conditions, such as asthma, viral infections,
or bacterial pneumonias. Congenital lung malformations include pulmonary hypoplasia (reduction in
bronchiole number and alveoli), pulmonary agenesis (absence of vasculature and lung tissue),
pulmonary aplasia (presence of rudimentary bronchus but absence of vasculature and lung tissue),
congenital cystic adenomatoid malformation (dysplastic lung tissue), congenital lobar emphysema
(idiopathic hyperinflation of one or more lobes), and pulmonary sequestration (lung tissue that has
a systemic arterial supply instead of pulmonary arterial supply and generally lacks bronchial
communication).

The boy described in the vignette has a classic presentation of pulmonary sequestration, which
accounts for 6% of all congenital lung malformations, occurs more commonly in the left lower lobe,
and has a male predominance. Sequestrations are classified as either intrapulmonary or
extrapulmonary, according to their presence inside or outside the visceral (inner) pleura. Affected
infants and children often present with chronic cough and recurrent respiratory infections in the
same anatomic location. Physical examination findings include dullness to percussion, with
decreased aeration over the affected area. Crackles frequently are audible during infection. Patients
who have large systemic arterial-to-venous shunts may present with a systolic murmur and exercise
intolerance. Radiographs demonstrate consolidation of the affected area, but often show air-filled
cystic lesions during active infections (Item C249).

Computed tomography scan is used to establish the diagnosis and plan surgical treatment, if
indicated. Aortography may be useful to determine vascular supply, but computed tomography with
angiography is preferable and is the initial step in the evaluation. Administration of amoxicillin with
future follow-up is neither curative nor appropriate. Thoracentesis is not helpful in establishing the
diagnosis. The child does not have symptoms consistent with gastroesophageal reflux and,
therefore, a pH probe is not indicated.

				
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