Paranasal Sinus Barotrauma
This most often involves the frontal or maxillary sinuses and the pressure differential usually causes the lining of the sinuses to become swollen and bleeding can ensue.
Nosebleed is a common event with diving and can be caused by negative pressure within the mask or from pressure change after ascent. Dull aching is present and treatment is directed at the use of nasal decingestants and symptomatic pain relief. Antibiotics are also used to treat infection.
Goldmann reported a case of sinus barotrauma presenting as air in the subdural space. (JAMA. 255:3154-3156, 1986.) There is really no difference between the damage and pain with descent or ascent. It occurs in both flyers and divers and the pathophysiology is the same–the inability to equilibrate the air pressure as it changes, up and down.
All of this depends mainly on the function of the mucosa of the nose and sinuses. Some people secrete large quantities of mucus in response to allergy. Others have a definite correctible problem, such as nasal septal deviation, polyps or tumors, resulting in blockage of the ostia (openings) of the sinuses.
The frontal sinuses are the most frequently involved, probably because the nasofrontal duct is longer and more tortuous. The damage that is done by the pressure change leads to a series of changes within the sinuses consisting of air absorption, decreased pressure in the sinus; swelling, engorgement, inflammation and fluid collection in the sinus cavity. This decrease becomes greater with descent (as with flying) the changes become greater, more painful and often associated with bleeding into the sinus cavity. On ascent, there is one-way valve blockage of the ostia, resulting in more barotrauma. The next step after all this is usually infection, which increases the blockage by causing it’s own swelling and purulent discharge.
Common causes of all this include, allergy; chronic irritation, such as smoking, diesel fumes, chemicals, prolonged use of nose drops or nasal sprays; mechanical blockage; vasomotor problems from chronic tension, stress or anxiety.
It should be obvious that what should be a very simple problem can be stubbornly difficult to diagnose and manage.