Practice Essentials
Barosinusitis is characterized by inflammation of one or more of the paranasal sinuses, with the inflammation being caused by a pressure gradient, almost always negative, between the sinus cavity and the surrounding ambient environment. [1, 2] Barotrauma of the paranasal sinuses is a risk factor for anyone exposed to ambient pressure changes. These pressure changes most often result from travel through mountainous regions, flying, or diving. [3, 4] Computed tomography (CT) scans are considered the criterion standard for imaging assessment of barosinusitis. Treatment is accomplished most simply by returning to the altitude at which symptoms occurred or, in the case of diving, returning to the surface.
Signs and symptoms
With mild sinus barotrauma, the patient reports the following:
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Mild pressure or pain over one or more of the sinuses that develops after return to sea level or starting point
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Worsening congestion
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Occasional epistaxis
With more severe sinus barotrauma, the patient notes the following possibly incapacitating signs and symptoms:
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Sudden onset of typically severe and sharp pain and pressure - Pain is typically in the forehead, midface, or retro-orbital area
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Epistaxis
Workup
Plain films are useful to isolate location, while CT scans are considered the criterion standard for imaging assessment of barosinusitis, with coronal and axial views being obtained. Magnetic resonance imaging (MRI) is similar to CT scanning in predicting involved sinuses, but it does not provide bony detail. MRI is better than CT scanning in differentiating paranasal sinus masses, although it is not as useful as CT scanning in surgical planning and can be more time consuming to obtain.
Management
Treatment is accomplished most simply by returning to the altitude at which symptoms occurred or, in the case of diving, returning to the surface. Decongest the nose with liberally applied topical agents, and then gradually descend to ground level.
Medical therapy is generally directed toward pain control, establishing ventilation, and preventing infection.
Surgical therapy is designed to restore sinus ventilation. Conventional therapy with septoplasty, turbinectomy, antral windows, the Caldwell-Luc operation, external or transantral ethmoidectomy, nasal polypectomy, and frontal sinus trephination has had variable efficacy. Endoscopic sinus surgery has substantially increased the chance of returning the patient to full activities.
Classification
Based on a literature review and clinical experience, Vaezeafshar et al proposed a new classification system for barosinusitis, consisting of the following subtypes [5] :
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Acute, isolated barosinusitis - The most common form of barosinusitis, this is defined as “an isolated episode of sinus-related pain and inflammation that lasts a few hours to days after exposure to an identifiable cause of change in ambient air pressure”
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Recurrent, acute baronsinusitis - Acute barosinusitis episodes that occur frequently, with patients being asymptomatic and displaying no clinical or radiologic signs of the condition in the intervening periods
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Chronic barosinusitis - The most severe subtype
Pathophysiology
The paranasal sinuses have rigid walls with relatively small ostia for gas exchange and mucus transport. Physical gas laws, particularly Boyle's Law, apply to this space. Boyle's Law states that at constant temperature, the volume of a gas is inversely proportional to the pressure placed upon it.
To show how Boyle's Law affects the sinuses, consider the case of an individual with normal sinuses exposed to pressure changes while flying in an unpressurized aircraft. As the individual transitions to higher altitude, the ambient pressure surrounding the sinus cavity decreases, and the air in the sinuses expands and equalizes through the natural ostium. Upon descent, ambient air pressure increases, the air in the sinuses contracts, and air moves into the sinus cavity, preventing a pressure gradient from developing.
Now consider the same flight in someone who has an upper respiratory tract infection (URTI) with tissue edema and secretions blocking the natural sinus ostia. In this individual, tissue edema and debris will not allow free pressure equalization. Again, as the individual moves up in altitude, the ambient pressure decreases, and volume in the sinus cavity increases. A positive pressure develops in the sinus. With this positive pressure, tissue edema gradually decreases enough to allow debris and air to escape the natural ostium. Air pressure then equalizes. When the individual descends, the ambient pressure increases. Pressure cannot equalize across the nasal cavity to the sinus because of blockage at the ostium. Air volume decreases in the sinus cavity, creating a negative pressure.
At this point, a condition exists in which the volume of the sinus must be filled if the pressure gradient is to be eliminated. In mild-to-moderate cases, vascular engorgement and generalized submucosal edema occur. Over time, transudate and mucus fill the volume, reducing negative pressure and decreasing symptoms. In severe cases, especially with rapid onset, the sinus mucosa is stripped from the subjacent bone, resulting in severe pain and hematoma formation.
Epidemiology
Frequency
United States
Prevalence is approximately 3-4 episodes per 100,000 exposures in a generally healthy population.
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In contrast, middle ear barotrauma (aerotitis media) is approximately 6-10 times more prevalent than barosinusitis.
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Frontal sinuses are most often affected, followed by maxillary sinuses.
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Ethmoid sinuses are infrequently affected as isolated events.
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Data are heavily skewed toward people who participate in activities subject to rapid pressure changes.
International
A Danish study conducted via questionnaire determined that compared with pilots who had answered the same questionnaire 10 years earlier, the proportion of responding pilots in whom one or more ear-nose-throat (ENT) barotraumas had occurred had increased from 19.5% to 27.9% for barosinusitis and from 37.4% to 55.5% for barotitis media. [6]
Race
Race predilection is not widely reported.
Sex
Sex predilection is not widely reported.
Age
Barosinusitis is not typically reported in children. Frontal sinuses are most frequently affected, and these do not fully develop until late adolescence. In addition, children do not routinely participate in activities that lend themselves to rapid pressure changes.
