What is the pathophysiology behind sinus barotrauma in divers?

• A. Viral infection
• B. Obstruction of sinus ostia causing pressure difference during dive
• C. Bacterial infection
• D. Allergic reaction

Answer: (B)

Sinus barotrauma happens when the air-filled sinus cannot equalize with the surrounding water pressure because the sinus drainage openings (ostia) are blocked. As a diver changes depth, ambient pressure rises or falls; if the ostia are obstructed by swelling or mucus, the air inside the sinus can’t vent or compress to match the new pressure. This creates a pressure difference across the sinus walls, distending and injuring the mucosa and sometimes causing bleeding or intense facial pain. While viral infections, allergies, or other causes of nasal mucosal swelling can predispose to obstruction, the essential mechanism is the blocked ostia preventing pressure equalization, not the infection itself.