Grade I includes cases with mild transient sinus discomfort without changes visible on X-ray.
Pressure inside the sinus increases, affecting the walls of the sinus and producing pain or epistaxis.Ĭambell and Weissman defined three grades of sinus barotraumas according to symptomatology. If the outlet is blocked during ascent, the situation is reversed and "reverse squeeze" appears. The sinus will fill with fluid or blood unless the pressure differential is neutralized. The pressure differentials are directed to the center of the sinuses producing mucosal edema, transudation, and mucosal-or submucosal-hematoma, leading to further occlusion of the sinus ostium. Squeeze is produced on descent when trapped air in the sinuses contracts and produces negative pressure. However, when the opening is obstructed due to inflammation, polyps, mucosal thickening, anatomical abnormalities, or other lesions, pressure equilibration is impossible. Normally, the sinuses drain into the nasal cavity through small ostia, which permit mucocilliary clearance and ventilation that equilibrates pressure. On ascent, the air in the paranasal sinuses will expand according to Boyle's law, contracting during descent. Two types of acute barotrauma are observed: squeeze and reverse squeeze. The pathology of sinus barotrauma is directly related to Boyle's law, which states that the volume of a gas is directly proportional to the pressure on it, when temperature is constant (P1 × V1 = P2 × V2). Rapid altitude changes with accompanying changes in ambient pressure exposed the aircrews to an increasing number of episodes of sinus barotrauma.Īlthough the environment of fighter pilots produces the most stressful barometric changes, commercial flying has changed the picture of the disease. However, it was during World War II that the subject first received serious attention and the pathogenesis of the disease was understood to be due to exposure to high altitude flights. Sinus barotrauma or aerosinusitis has been known since the early development of aviation medicine. Neurological symptoms may affect the adjacent fifth cranial nerve and especially the infraorbital nerve. Epistaxis or serosaquineous secretion from the nose may occur. Less common is pain referred to the temporal, occipital, or retrobulbar region. In most cases of sinus baratrauma, localized pain to the frontal area is the predominant symptom.
Ultimately fluid or blood will fill the space. The pressure difference causes the mucosal lining of the sinuses to become swollen and submucosal bleeding follows with further difficulties ventilating the sinus, especially if the orifices are involved. The pain can ultimately become disabling unless the ambient pressure is reversed. The affected person suffers a sudden sharp facial pain or headache during descent, which increases as the aircraft approaches ground level. Typically, sinus barotrauma is preceded by an upper respiratory tract infection or allergy. On the other hand, the problem may remain undiagnosed when the history fails to relate the symptoms to exposure to environmental pressure changes or if the focus is on other etiologies. Most cases occur in Scuba divers and fliers, and are easily diagnosed when presented to physicians immediately after exposure. Safe Weighing Range Ensures Accurate Results
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