Sinus Barotrauma

Sinus barotrauma is pain and mucosal injury in the paranasal sinuses from unequal pressure when the ostia are blocked during diving, flying or hyperbaric exposure. The frontal sinus is most often involved, followed by the maxillary sinuses.

Epidemiology. Common in divers and aircrew. It occurs mainly on descent as sinus gas contracts, but can follow ascent when expansion is trapped.

Risk factors. Upper respiratory infection, allergic rhinitis, polyps, septal deviation, concha bullosa, previous sinus surgery and decongestant overuse.

Severity. Mostly mild and self-limited. Mucosal haemorrhage, fluid in the sinus and, rarely, fractures or pneumocephalus occur.

Pathophysiology.

A closed ostium traps gas at lower pressure than outside, so the mucosa swells and bleeds and the sinus fills with transudate and blood (vacuum effect). On ascent, trapped expanding gas causes pain and can force gas through thin bone.

• Sudden frontal or facial pain on descent, worse with pressure, sometimes with bleeding from the nose after surfacing.
• Maxillary involvement gives cheek pain and toothache, or numbness in the infraorbital nerve area.
• Tenderness over the sinus, often resolving over days.

Red flags.

• Severe headache with neurological signs, clear nasal fluid or neck stiffness (pneumocephalus, skull base injury, cerebrospinal fluid leak).
• Orbital swelling, visual change or double vision.
• Fever with purulent discharge or persistent pain (sinusitis).

• Dive and flight history, nasal symptoms and prior sinus disease.
• Examination of sinuses, nose and cranial nerves; nasal endoscopy when recurrent.
• CT sinuses for severe, recurrent or suspicious cases: fluid, haemorrhage, polyps and anatomic variants.

Differential diagnosis. Acute bacterial sinusitis, middle ear barotrauma, dental pain, migraine, trigeminal neuralgia, facial fracture.

• Avoid diving and flying until symptoms settle and the diver can equalise; allow 1 to 2 weeks for mild injury.
• Paracetamol 1 g orally every 6 hours as needed, maximum 4 g in 24 hours (3 g if under 50 kg, chronic alcohol excess or liver disease), for the shortest period that controls pain. Reduce dose in hepatic impairment; extend dosing interval when eGFR is under 30.
• Mometasone nasal spray 50 micrograms/spray, 2 sprays into each nostril once daily for 2 to 4 weeks. Maximum 200 micrograms daily. Monitor for nosebleeds. Avoid in untreated nasal infection; no renal adjustment.
• Short term oxymetazoline 0.05% spray, 2 sprays into each nostril twice daily for no more than 3 days. Maximum 3 days. Monitor blood pressure and rebound congestion; avoid in uncontrolled hypertension. Not to be used just before diving.
• Suspected bacterial sinusitis: amoxicillin 500 mg orally three times daily for 5 days. Maximum 1 g three times daily. Monitor for rash and diarrhoea. If eGFR is 10 to 30 give 500 mg every 12 hours; under 10, 500 mg every 24 hours; avoid in penicillin allergy and use doxycycline 200 mg orally on day 1 then 100 mg once daily for 4 days (avoid in pregnancy and under 12 years).
• Recurrent or anatomical blockage: ENT assessment for surgery.

Monitoring. Review at 1 to 2 weeks; repeat after any new dive.

Referral and escalation. ENT for recurrent, severe or anatomical disease; urgent assessment for any red flag; diving physician for return-to-diving clearance.