Pediatric lower airway conditions: Clinical

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Pediatric lower airway conditions: Clinical

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USMLE® Step 2 style questions USMLE

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A 3-week-old female infant comes to the emergency department because of fever and minimally productive cough for the past five days. Her parents state that she was delivered at 37 weeks’ gestation and weighed 1.4-kg (3.1-lb) at birth. Physical examination shows an infant in mild respiratory distress with a disseminated petechial rash. A representative histological specimen of the patient’s lung is shown below. The patient is admitted to the hospital and given intravenous therapy for her infection. One week later, her respiratory symptoms have improved. A complete metabolic panel (CMP) and complete blood count (CBC) are obtained and shows the following values:  

Alanine aminotransferase (ALT): 47 U/L
Aspartate aminotransferase (AST): 56 U/L
Sodium: 140 mEq/L
Potassium: 3.7 mEq/L
Chloride: 96 mEq/L
Blood urea nitrogen (BUN): 12 mg/dL
Creatinine: 0.8 mg/dL
Glucose: 79 mg/dL
Erythrocytes: 3,850,000/mm3
Leukocytes: 2,900/mm3
Platelets: 90,000/mm3

Which of the following medications was most likely administered to the patient?



The lower airways include the trachea, bronchi, bronchioles and lungs and can be affected by a number of distinct pathologies in children.

Let’s start with foreign body aspiration, which is where young toddlers might get something like a small coin or a peanut, lodged in their respiratory tract.

Most of the time, the foreign body goes into the right mainstem bronchus because it’s wider and more vertical than the left.

In general, if the blockage affects a larger airway or causes a more complete blockage of an airway, then it causes more severe symptoms.

Typically, children have a sudden onset of shortness of breath, along with coughing, gagging, choking, or drooling.

On auscultation, breath sounds are diminished in blocked area.

If there’s partial obstruction of the extrathoracic portion of the trachea, that can cause inspiratory stridor.

If there’s expiratory wheezing, that means that there’s partial obstruction of either the intrathoracic trachea, bronchi, or bronchioles. And that wheezing will be localized to the blocked area.

If there are no sounds like this on auscultation, it may be because there’s a complete obstruction of an airway.

If a foreign body aspiration is suspected, it’s important to do a neck or chest radiograph.

Objects like coins and batteries are radiopaque, and will be visible. Whereas objects like a piece of food are radiolucent, so they don’t show up.

Fortunately, there are still indirect signs of the obstruction that can be seen on a chest Xray. In a complete obstruction, there’s atelectasis distal to the obstruction.

In a partial obstruction, there’s focal hyperlucency and reduced pulmonary markings distal to the obstruction, due to air trapping. In other words, the foreign body acts like a one way valve that allows air to enter, but not escape.

If there’s a lot of air trapping, it can cause a mediastinal shift away from the affected side.


Pediatric lower airway conditions are the disorders that affect children's trachea, bronchi, bronchioles, or lungs. Common examples include foreign body aspiration, asthma, bronchiolitis, croup, and pneumonia. These conditions can cause symptoms such as cough, wheezing, shortness of breath, and difficulty breathing. Treatment depends on the specific condition and may include medications, breathing therapies, and in some cases, surgery.


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