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Answer 26 of 50

Pleural Disease

A 5-year-old known asthmatic develops sudden breathlessness and right sided chest pain during an exacerbation. He is alert, blood pressure is normal for age and the trachea is central. The right chest is hyperresonant to percussion with markedly reduced air entry, and oxygen saturation is 88 percent in room air.

What is the most likely diagnosis?

Correct answer: B — Pneumothorax

Sudden unilateral hyperresonance with reduced air entry in an asthmatic child is pleural air, and a central trachea with a normal blood pressure makes it a simple rather than a tension pneumothorax.

Air trapping in acute asthma over distends alveoli until one ruptures into the pleural space, the mechanism of secondary spontaneous pneumothorax.
Percussion separates the look-alikes: pleural air is hyperresonant, while consolidation or collapse is dull with reduced air entry.
Tension is a hemodynamic diagnosis, so a central trachea and a blood pressure normal for age rule it out at this moment.
Hypoxemia is expected in a simple pneumothorax because blood still perfuses the collapsed lung, and it does not upgrade the diagnosis to tension.
Sudden chest pain and breathlessness that do not fit the wheeze should always prompt examination for an air leak before escalating asthma treatment.

★ Clinical pearl

In a wheezy child who suddenly worsens, percuss: hyperresonance with reduced air entry is air in the pleura, dullness is fluid or consolidation.

Exam note

Recalls disagree between pneumothorax and tension pneumothorax and no answer key is ever published, so the key is set by the medicine and not by the tally. A simple pneumothorax is correct, because tension is a hemodynamic diagnosis and this child has a central trachea, a normal blood pressure and normal perfusion, while the low saturation only reflects shunt through the collapsed lung, and most recalls give the same answer. A minority answer tension pneumothorax, which would be right only if the stem added tracheal or apical shift, distended neck veins or shock, and that child needs immediate needle decompression before any film.

Go deeper — why the other options fail, and what candidates recalled

Option	Why not
A	Pneumatoceles are thin walled cysts appearing during or after a necrotizing pneumonia, so the child is febrile with consolidation rather than suddenly breathless while wheezy.
C	Tension would show a shifted trachea or apex, distended neck veins and hypotension with poor perfusion, none of which is present.
D	Lobar pneumonia gives fever, dullness to percussion and bronchial breathing, the opposite percussion note to this.

What candidates actually recalled: Pneumothorax (found in 2 recall sets)

Consistent with GINA

Case Complete