Master the board step 3

Master the Boards: USMLE Step 3
Differentiate epiglottitis
from croup by the absence
of a barking cough.
Clues to less common disorders:
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Diphtheritic croup (extremely rare in North America): Presents with a
gray-white pharyngeal membrane; may cover soft palate; bleeds easily. Don’t
forget that diphtheria is a notifiable disease!
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Foreign body aspiration: Look for sudden choking/coughing without
warning.
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Retropharyngeal abscess: Patient has drooling and difficulty swallowing.
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Extrinsic compression (vascular ring) or intraluminal obstruction (masses):
Patient has continued symptoms and does not improve with treatment.
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Angioedema: This is due to a sudden allergic reaction. (Trigger is given
in the case.) Manage with steroids and epinephrine. If severe, intubate for
airway protection. Angioedema is mediated by bradykinin. This peptide
increases the permeability of the vasculature, leading to the accumulation
of fluid.
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Pertussis: Severe cough develops after 1–2 weeks with characteristic whoop
and spells of cough (paroxysms). Look for child with incomplete immunization
history.
The most common sites of
foreign body aspiration are
the following:
• In children > 1 year:
Larynx
• In children < 1 year:
Trachea or right
mainstem bronchus
A toddler presents to the emergency center with sudden onset respiratory distress.
The mother reports that the child was without symptoms, playing with
LEGOS in the living room with her siblings. On physical examination, the patient is
drooling and in moderate respiratory distress. There are decreased breath sounds
on the right with intercostal retractions. Which of the following is the most appropriate
next step in management?
a. Antibiotics
b. Bronchoscopy
c. Chest x-ray
d. Cricothyroidotomy
e. Throat cultures
Answer: B. Bronchoscopy is indicated both to visualize a suspected foreign body and
for foreign body retrieval. If there is significant respiratory distress and hypoxemia,
emergency cricothyroidotomy may be indicated. Foreign bodies are found most commonly
in children < 4 years.
Recurrent infections in a young child should always raise the suspicion of previously
undiagnosed aspiration. Get a chest x-ray to look for postobstruction
atelectasis or visualization of the foreign body.
Best prevention
against bronchiolitis is
breastfeeding. Colostrum
is particularly rich in IgA
and protects against
bronchiolitis.
Inflammation of the Small Airways
Bronchiolitis
The pathophysiology of bronchiolitis is as follows:
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Respiratory syncytial virus (RSV) (50 percent)
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Parainfluenza
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