Aerosinusitis
Encyclopedia
Aerosinusitis, also called barosinusitis, sinus squeeze or sinus barotrauma
is a painful inflammation
and sometimes bleeding of the membrane
of the paranasal sinus
cavities, normally the frontal sinus
. It is caused by a difference in air pressures inside and outside the cavities.
and fliers
, and is easily diagnosed when presented to physicians immediately after exposure. 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
.
Typically, sinus barotrauma
is preceded by an upper respiratory tract infection or allergy
. The affected person suffers a sudden sharp facial pain or headache during descent, which increases as the aircraft approaches ground level. The pain can ultimately become disabling unless the ambient pressure is reversed.
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. Ultimately fluid or blood will fill the space.
In most cases of sinus barotrauma, localized pain to the frontal area is the predominant symptom. This is due to pain originating from the frontal sinus, it being above the brow bones. Less common is pain referred to the temporal, occipital, or retrobulbar region. Epistaxis or serosaquineous secretion from the nose may occur. Neurological symptoms may affect the adjacent fifth cranial nerve and especially the infraorbital nerve.
Sinus barotrauma or aerosinusitis has been known since the early development of aviation medicine
. 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. Rapid altitude changes with accompanying changes in ambient pressure exposed the aircrews to an increasing number of episodes of sinus barotrauma.
Referred pain
from barosinusitis to the maxilla
consists about one-fifth of in-flight barodontalgia
(i.e., pain
in the oral cavity caused by barometric pressure change) cases.
Although the environment of fighter pilots produces the most stressful barometric changes, commercial flying has changed the picture of the disease.
The pathology of sinus barotrauma is directly related to Boyle's law
, which states that the volume of a gas is inversely proportional to the pressure on it, when temperature is constant (P1 × V1 = P2 × V2).
Two types of acute barotrauma are observed: squeeze and reverse squeeze.
On ascent, the air in the paranasal sinus
es will expand according to Boyle's law, contracting during descent. Normally, the sinuses drain into the nasal cavity
through small ostia
, which permit mucocilliary clearance and ventilation that equilibrates pressure. However, when the opening is obstructed due to inflammation, polyps, mucosal thickening, anatomical abnormalities, or other lesions, pressure equilibration is impossible. Squeeze is produced on descent when trapped air in the sinuses contracts and produces negative pressure. 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. The sinus will fill with fluid or blood
unless the pressure differential is neutralized.
If the outlet is blocked during ascent, the situation is reversed and "reverse squeeze" appears. Pressure inside the sinus increases, affecting the walls of the sinus and producing pain or epistaxis.
that connects the narrow frontal recess with the frontal sinuses.
Barotrauma located in the maxillary
, ethmoidal, or sphenoid sinuses is observed less frequently and appears when the ostia
are blocked; the majority of cases are probably caused by an acute upper respiratory tract infection. The magnitude of the pressure difference needed to produce a barotrauma probably shows great individual variation and is related to the size of the sinus ostium and the rate of ambient pressure change. Due to this, even commercial flying may produce severe cases of barotraumas, although most of the cases are observed in high performance aircraft with lower pressurized cabins.
Barotrauma
Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding fluid...
is a painful inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
and sometimes bleeding of the membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
of the paranasal sinus
Paranasal sinus
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
cavities, normally the frontal sinus
Frontal sinus
Sinuses are mucosa-lined airspaces within the bones of the face and skull. The frontal sinuses, situated behind the superciliary arches, are absent at birth, but are generally fairly well developed between the seventh and eighth years, only reaching their full size after puberty...
. It is caused by a difference in air pressures inside and outside the cavities.
Presentation and diagnosis
Most cases occur in scuba diversScuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
and fliers
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
, and is easily diagnosed when presented to physicians immediately after exposure. 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
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
.
Typically, sinus barotrauma
Barotrauma
Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding fluid...
is preceded by an upper respiratory tract infection or allergy
Allergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
. The affected person suffers a sudden sharp facial pain or headache during descent, which increases as the aircraft approaches ground level. The pain can ultimately become disabling unless the ambient pressure is reversed.
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. Ultimately fluid or blood will fill the space.
In most cases of sinus barotrauma, localized pain to the frontal area is the predominant symptom. This is due to pain originating from the frontal sinus, it being above the brow bones. Less common is pain referred to the temporal, occipital, or retrobulbar region. Epistaxis or serosaquineous secretion from the nose may occur. Neurological symptoms may affect the adjacent fifth cranial nerve and especially the infraorbital nerve.
Sinus barotrauma or aerosinusitis has been known since the early development of aviation medicine
Aviation medicine
Aviation medicine, also called flight medicine or aerospace medicine, is a preventive or occupational medicine in which the patients/subjects are pilots, aircrews, or persons involved in spaceflight...
. However, it was during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
that the subject first received serious attention and the pathogenesis of the disease was understood to be due to exposure to high altitude flights. Rapid altitude changes with accompanying changes in ambient pressure exposed the aircrews to an increasing number of episodes of sinus barotrauma.
Referred pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
from barosinusitis to the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
consists about one-fifth of in-flight barodontalgia
Barodontalgia
Barodontalgia, commonly known as tooth squeeze and previously known as aerodontalgia, is a pain in tooth caused by a change in atmospheric pressure...
(i.e., pain
Toothache
A toothache, also known as odontalgia or, less frequently, as odontalgy, is an aching pain in or around a tooth.-Causes:* Dental etiology, In most cases toothaches are caused by problems in the tooth or jaw, such as** Dental caries...
in the oral cavity caused by barometric pressure change) cases.
Although the environment of fighter pilots produces the most stressful barometric changes, commercial flying has changed the picture of the disease.
The pathology of sinus barotrauma is directly related to Boyle's law
Boyle's law
Boyle's law is one of many gas laws and a special case of the ideal gas law. Boyle's law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system...
, which states that the volume of a gas is inversely proportional to the pressure on it, when temperature is constant (P1 × V1 = P2 × V2).
Two types of acute barotrauma are observed: squeeze and reverse squeeze.
On ascent, the air in the paranasal sinus
Paranasal sinus
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
es will expand according to Boyle's law, contracting during descent. Normally, the sinuses drain into the nasal cavity
Nasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
through small ostia
Ostium
Ostium may refer to:Anatomy*Ostium of Fallopian tube*Ostium primum or foramen ovale of the developing heart*Ostium maxillare of the maxillary sinus*Ostium of female lepidoptera genitalia...
, which permit mucocilliary clearance and ventilation that equilibrates pressure. However, when the opening is obstructed due to inflammation, polyps, mucosal thickening, anatomical abnormalities, or other lesions, pressure equilibration is impossible. Squeeze is produced on descent when trapped air in the sinuses contracts and produces negative pressure. The pressure differentials are directed to the center of the sinuses producing mucosal edema, transudation, and mucosal-or submucosal-hematoma
Hematoma
A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...
, leading to further occlusion of the sinus ostium. The sinus will fill with fluid or blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
unless the pressure differential is neutralized.
If the outlet is blocked during ascent, the situation is reversed and "reverse squeeze" appears. Pressure inside the sinus increases, affecting the walls of the sinus and producing pain or epistaxis.
Grades
Weissman defined three grades of sinus barotraumas according to symptomatology.- Grade I includes cases with mild transient sinus discomfort without changes visible on X-ray.
- Grade II is characterized by severe pain for up to 24 h, with some mucosal thickening on X-ray.
- Patients with grade III have severe pain lasting for more than 24 h and X-ray shows severe mucosal thickening or opacification of the affected sinus; epistaxis or subsequent sinusitis may be observed.
Location
The majority of episodes of sinus barotrauma occur in the frontal sinuses with pain localized over the frontal area. Possible explanations for this might be the relatively long and delicate nasofrontal ductNasofrontal duct
The nasofrontal duct is a duct connecting the infundibulum and frontal sinus.A true nasofrontal duct only exists in 15% of the population.Some sources prefer the term "frontal recess"....
that connects the narrow frontal recess with the frontal sinuses.
Barotrauma located in the maxillary
Maxillary sinus
The pyramid shaped maxillary sinus is the largest of the paranasal sinuses, and drains into the nose. It is present at birth as rudimentary air cells, and develops throughout childhood.-General characteristics:...
, ethmoidal, or sphenoid sinuses is observed less frequently and appears when the ostia
Ostium
Ostium may refer to:Anatomy*Ostium of Fallopian tube*Ostium primum or foramen ovale of the developing heart*Ostium maxillare of the maxillary sinus*Ostium of female lepidoptera genitalia...
are blocked; the majority of cases are probably caused by an acute upper respiratory tract infection. The magnitude of the pressure difference needed to produce a barotrauma probably shows great individual variation and is related to the size of the sinus ostium and the rate of ambient pressure change. Due to this, even commercial flying may produce severe cases of barotraumas, although most of the cases are observed in high performance aircraft with lower pressurized cabins.