Which sign may indicate a pneumothorax in a patient with cystic fibrosis?

• A. Drop in oxygen saturation
• B. Fever
• C. Rash
• D. Nausea

Answer: (A)

A pneumothorax disrupts ventilation in part of the lung, which immediately reduces gas exchange and can cause a noticeable drop in oxygen saturation. In cystic fibrosis, fragile lung tissue and blebs increase the risk of air leaking into the pleural space, so a sudden decrease in SpO2 is a direct and important sign that the lung isn’t oxygenating properly anymore.

Fever, Rash, and Nausea aren’t specific indicators of a pneumothorax. Fever could point to infection, rash to hypersensitivity or other conditions, and nausea to GI or systemic issues. They don’t reflect the acute loss of lung ventilation that a pneumothorax causes.