ALTERNOBARIC VERTIGO--A DIVING HAZARD

A Case Report on Ground-Level Alternobaric Vertigo Due to Eustachian Tube Dysfunction With the Assistance of Conversational Generative Pre-trained Transformer (ChatGPT)

Alternatenobaric vertigo (ABV) develops when the middle ear pressure (MEP) is not equal at the same height in the sea or the air. This is possible when the altitude changes. Eustachian tube dysfunction (ETD) is a common cause of ABV. In this case report, we discuss a patient who experienced repeated bouts of ground-level alternobaric vertigo (GLABV) due to ETD. We also discuss how Conversational Generative Pre-trained Transformer (ChatGPT) might be used in the creation of this case report. A 41-year-old male patient complained of vertigo at ground level on several occasions. His medical history included chronic sinusitis, nasal congestion, and laryngopharyngeal reflux (LPR). During the physical exam, his tympanic membranes were dull and moved less. Tympanometry showed that he had an asymmetric type A and that both of his middle ears had negative pressure. The results of the audiometry test were normal, and the laryngoscopy revealed LPR. The patient was found to have GLABV because of ETD, and different treatment options, such as Eustachian tube catheterization (ETC), were thought about. This case study demonstrates how ChatGPT can be used to assist with medical documentation and the treatment of GLABV caused by ETD. Even though ChatGPT did not provide specific diagnostic or treatment recommendations for the patient's condition, it did assist the doctor in determining what was wrong and how to treat it while writing the case report. It also aided the doctor in writing the case report by allowing them to discuss it. The use of artificial intelligence (AI) tools such as ChatGPT has the potential to improve the accuracy and speed of medical documentation, thereby streamlining clinical workflows and improving patient care. Nonetheless, it is critical to consider the ethical implications of using AI in clinical practice This case study emphasizes the importance of understanding that ETD is a common cause of GLABV and how ChatGPT can aid in the diagnosis and treatment of this condition. More research is needed to fully understand how long-term AI interventions in medicine work and how reliable they are.

Lowering barometric pressure induces neuronal activation in the superior vestibular nucleus in mice

Weather changes accompanied by decreases in barometric pressure are suggested to trigger meteoropathy, i.e., weather-related pain. We previously reported that neuropathic pain-related behavior in rats is aggravated by lowering barometric pressure, and that this effect is abolished by inner ear lesions. These results suggest that mechanisms that increase vestibular neuronal activity may parallel those that contribute to meteoropathy generation. However, it remains unknown whether changes in barometric pressure activate vestibular neuronal activity. To address this issue, we used expression of c-Fos protein as a marker for neural activation. Male and female mice were placed in a climatic chamber, and the barometric pressure was lowered by 40 hPa, from 1013 hPa, for 50 min (LP stimulation). The total number of c-Fos-positive cells in the vestibular nuclei was counted bilaterally after LP stimulation. We also video-recorded mouse behaviors and calculated the total activity score during the LP stimulation. LP stimulation resulted in significant c-Fos expression in the superior vestibular nucleus (SuVe) of male and female mice. There was no effect of LP stimulation on the total activity score. These data show that distinct neurons in the SuVe respond to LP stimulation. Similar mechanisms may contribute to the generation of meteoropathy in humans.

Otologic Hazards Related to Scuba Diving

Context:

As of 2015, more than 23 million scuba diver certifications have been issued across the globe. Given the popularity of scuba diving, it is incumbent on every physician to know and understand the specific medical hazards and conditions associated with scuba diving.

Evidence Acquisition:

Sources were obtained from PubMed, MEDLINE, and EBSCO databases from 1956 onward and ranged from diverse fields including otologic reviews and wilderness medicine book chapters.

Study Design:

Clinical review.

Level of Evidence:

Level 5.

Results:

Otologic hazards can be categorized into barotrauma-related injuries or decompression sickness.

Conclusion:

When combined with a high index of suspicion, the physician can recognize these disorders and promptly initiate proper treatment of the potentially hazardous and irreversible conditions related to scuba diving.

Ear and vestibular symptoms in train operators after sudden air pressure changes in trains

A healthy 31-year-old train operator presented to our occupational health clinic reporting ear aches, headaches, dizziness, unsteadiness and even slight tinnitus. These symptoms first appeared when the patient started operating from a new train cabin. He described a sudden pressure gradient, experienced on some parts of the trajectory, which might have caused these problems. Although the cabins were equipped with a pressure equalising device, this was usually switched off because of the device creating an uncomfortable feeling in the cabin. The literature describes sudden pressure gradients as possible factors for passenger discomfort.

Altered eustachian tube function in SCUBA divers with alternobaric vertigo

OBJECTIVES

The number of people participating in sport self-contained underwater breathing apparatus (SCUBA) diving has increased tremendously, bringing with it a rise in diving accidents. Alternobaric vertigo (AV) is a common problem in SCUBA divers. We investigated the relationship between Eustachian tube function and incidence of AV in sport SCUBA divers. We also followed the progress of these divers after Eustachian tube function improved.

METHOD

Forty-four patients who experienced a SCUBA diving accident affecting the middle ear (11 men and 33 women; mean ± SD: 37.5 ± 11.5 yr) and 20 healthy volunteer divers who did not experience an accident (6 men and 14 women; mean ± SD: 33.5 ± 13.9 yr) were compared. We divided the divers with an accident into two groups (those with AV vs. those without) and then compared the two groups. All patients regularly underwent Eustachian tube function tests (sonotubometry and impedance test).

RESULTS

In sonotubometry and impedance testing, the mean duration (p < 0.001), amplitude (p < 0.002), and maximum air content (p < 0.05) of divers who experienced a diving accident were significantly different from those of healthy volunteers. However, these parameters in divers with AV did not differ significantly from those in divers without AV. In 7 of 15 divers, vestibular symptoms disappeared immediately after ascent. In the remaining eight divers, however, vertigo/dizziness persisted and even was observed at their first clinic visit.

CONCLUSION

To prevent AV or barotraumas in SCUBA divers, we recommend a thorough Eustachian tube function evaluation. Any dysfunction should be treated before engaging in SCUBA diving.

Auditory complaints in scuba divers: an overview

Pre-1970s, diving was seen as a predominantly male working occupation. Since then it has become a popular hobby, with increasing access to SCUBA diving while on holiday. For a leisure activity, diving puts the auditory system at the risk of a wide variety of complaints. However, there is still insufficient consensus on the frequency of these conditions, which ultimately would require more attention from hearing-healthcare professionals. A literature search of epidemiology studies of eight auditory complaints was conducted, using both individual and large-scale diving studies, with some reference to large-scale non-diving populations . A higher incidence was found for middle ear barotrauma, eustachian tube dysfunction, and alternobaric vertigo with a high correlation among females. Comparing these findings with a non-diving population found no statistically significant difference for hearing loss or tinnitus. Increased awareness of health professionals is required, training, and implementation of the Frenzel technique would help resolve the ambiguities of the Valsalva technique underwater.

Persistent alternobaric vertigo at ground level

We recently encountered a 15-year-old female with bilateral tympanostomy tubes who manifested persistent severe vertigo, at ground level, secondary to a unilateral middle-ear pressure of +200 mm H(2)O elicited by an obstructed tympanostomy tube in the presence of chronic nasal obstruction. We believe this is a previously unreported scenario in which closed-nose swallowing insufflated air into her middle ears, resulting in sustained positive middle-ear pressure in the ear with the obstructed tube. Swallowing, when the nose is obstructed, can result in abnormal negative or positive pressures in the middle ear, which has been termed the Toynbee phenomenon. In patients who have vertigo, the possibility that nasal obstruction and the Toynbee phenomenon are involved should be considered.

ENT morbidity at high altitude

BACKGROUND

People suffer unique health problems in high altitude areas, due to such factors as elevation, aircraft ascent and descent, extreme cold, hypoxia, hypobaria, and low relative humidity. This study was conducted to evaluate ENT morbidity at high altitude.

METHODS

Serving soldiers introduced to a high altitude environment who presented with various ENT symptoms were examined to identify ENT disease. In addition, patients undergoing hyperbaric chamber therapy, tracheostomy and treatment of cold injuries were also examined for ENT problems.

RESULTS

The following were detected: 13 cases of otic barotrauma, 11 cases of sinus barotrauma, three cases of vertigo, six cases of pinna frostbite, three cases of barotrauma caused by hyperbaric chamber therapy, an unusually high incidence of epistaxis, and innumerable patients with high altitude pharyngitis.

CONCLUSION

Diseases of the ear, nose and throat contribute significantly to high altitude morbidity. In a military context, health education of troops is necessary to avoid such problems.

The inner ear is involved in the aggravation of nociceptive behavior induced by lowering barometric pressure of nerve injured rats

Patients suffering from neuropathic pain often complain of pain aggravation when the weather is changing. The exact mechanism for weather change-induced pain has not been clarified. We have previously demonstrated that experimentally lowering barometric pressure (LP) intensifies pain-related behaviors in rats with chronic constriction injury (CCI). In the present experiment we examined whether this pain aggravating effect of LP exposure in nerve injured rats is still present after lesioning of the inner ear. We used both CCI and spinal nerve ligation (SNL) models for this study. We injected into the middle ear sodium arsanilate solution (100mg/ml, 50microl/ear), which is known to degenerate vestibular hair cells, under anesthesia the day before surgery. Rats were exposed to LP (27hPa decrease over 8min) 7-9 days after CCI or 5-8 days after SNL surgery, and pain-related behavior (number of paw lifts induced by von Frey hair stimuli) was measured. When the inner ear lesioned SNL or CCI rats were exposed to LP, they showed no augmentation of pain-related behavior. On the other hand, the pain aggravating effect of a temperature decrease (from 24 to 17 degrees C) was maintained in both SNL and CCI rats. These results suggest that the barometric sensor/sensing system influencing nociceptive behavior during LP in rats is located in the inner ear.

Alternobaric vertigo--really a hazard?

OBJECTIVE

To determine the prevalence of alternobaric vertigo (AV) in sport divers and to find out whether AV led to dangerous situations underwater. Furthermore, to examine whether objective neurootologic tests are associated with the manifestation of AV.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Sixty-three sport divers with an average diving experience of 10 years and 650 dives were questioned regarding their medical and diving history and the manifestation of vertigo during diving.

METHODS

Microscopic otoscopy, tympanometry, stapedius reflexes, hearing threshold for air and bone conduction, caloric video-oculography including analysis of the slow-phase velocity of the nystagmus, acoustic brain stem responses, and magnetic resonance imaging were performed to find possible differences between divers with and without AV.

RESULTS

We found 17 divers with AV (27%). There was no significant difference in all measured parameters apart from sex and history of middle ear equalization difficulty in divers with AV. Ten (59%) of 17 female divers and 7 (15%) of 46 male divers experienced AV, representing a significant sex difference (p < 0.001). Correlation with our divers' outpatient clinic revealed that female divers had a significantly higher incidence of middle ear equalization disorders which could be an explanation for the predominance of female divers with symptoms of AV. None of the divers reported any dangerous or life-threatening situations following AV. Whether AV leads to dangerous situations underwater remains unclear, but this hypothesis is not supported by our data.

CONCLUSION

Alternobaric vertigo is a common finding in divers. In our study group, female divers had a four-time higher risk to suffer AV. Our data do not support the thesis that AV is a life-threatening condition.

Alternobaric vertigo: prevalence in Portuguese Air Force pilots

CONCLUSION

Having found a prevalence rate of alternobaric vertigo in Portuguese Air Force pilots that is somewhat higher than previously reported, we underline the importance of implementing education on the management of this condition as part of routine Air Force pilot training programs.

OBJECTIVES

Alternobaric vertigo is a condition in which transient vertigo with spatial disorientation occurs suddenly during flying or diving activities, caused by bilateral asymmetrical changes in middle ear pressure. Its prevalence is very likely underestimated and under-reported, with the 10-17% prevalence rate mentioned in early literature not being challenged by recent data.

SUBJECTS AND METHODS

To assess its actual prevalence, the authors requested all high performance aircraft pilots presently on active duty in the Portuguese Air Force to anonymously answer a questionnaire on alternobaric vertigo symptoms, after a short briefing on the subject.

RESULTS

A 29% prevalence rate of in-flight episodes consistent with alternobaric vertigo was obtained.

Barotrauma

Barotrauma is pressure-induced injury. The application of direct pressure to the body may cause trauma, including positive pressure from artificial ventilation. Trauma may also be caused by the effects of pressure changes on gas-containing body spaces, not in communication with the environment. This can include the external ear, the middle ear (and, indirectly, the inner ear), the para-nasal sinuses, the lungs, the gut, and abscess cavities (for example, in the teeth). Gas may penetrate tissues adjoining the affected space (such as the anterior cranial fossa, via the ethmoid sinus), or may embolise via the blood stream. The most severe expression of this is cerebral arterial gas embolism, which may present as a stroke. The management of these problems includes prevention, the use of pressure-equalizing techniques, vasoconstrictor drugs, surgery, and hyperbaric oxygen therapy.

Involvement of round and oval windows in the vestibular response to pressure changes in the middle ear of guinea pigs

Changes in ambient pressure can elicit the vertigo and bodily disequilibrium known clinically as alternobaric vertigo. Our previous studies showed that changes in middle ear pressure altered the activity of the primary vestibular neuron, and the finding suggests that the pressure-induced vestibular response causes alternobaric vertigo. To investigate the roles played by the round window (RW) and the oval window (OW) in the vestibular response induced by pressure, we measured the change in perilymphatic pressure and the firing rates of primary vestibular neurons after the application of positive or negative pressure to the middle ear. We found an increase in the pressure-induced vestibular response in the group with a closed OW, and a decrease in the group with a closed RW. Measurements showed that the amplitude of the change in perilymphatic pressure in the group with a closed OW did not differ from that in the control group, whereas the amplitude of the perilymphatic pressure change in the group with a closed RW was significantly reduced. A discrepancy between the number of neurons responding and the amplitude of the perilymphatic pressure change in the closed OW group suggests that the vestibular response induced by the change in middle ear pressure was not related solely to the magnitude of the pressure change in the inner ear, but also involved the oval and round windows.

The influence of vestibular and cochlear aqueducts on vestibular response to middle ear pressure changes in guinea pigs

The responses of primary vestibular neurons and perilymphatic pressure changes to middle ear pressure were investigated in guinea pigs with obstructed vestibular or cochlear aqueduct (closed VA or closed CA group) in order to clarify the influence of VA and CA on pressure-induced vestibular response. Although the neural response rates and the amount of perilymphatic pressure change in the closed VA group resembled those in the control group, these values in the closed CA group were higher than in the control group. Patency of the CA had a more significant effect on the vestibular response to middle ear pressure change than patency of the VA.

A soundproof pressure chamber

For neurotological research we designed a soundproof pressure chamber in which pressure can be adjusted +/- 1000 mmH2O at the rate of less than 100 mmH2O per second. Noise in the chamber can be maintained under 30-35 dB while pressure is kept at a given level.

Effect of atmospheric pressure on hearing in normal subjects

Hearing is assumed to be altered during or immediately after a change in atmospheric pressure, although this has not been tested experimentally. We used a soundproof pressure chamber to examine the effect of alterations in atmospheric pressure on hearing in 26 normal healthy subjects. The subjects were placed in the soundproof pressure chamber in a supine position and instructed to actively equilibrate middle ear pressure or to abstain from doing so. When the pressure was changed to +/- 500 mmH2O at 33 mmH2O/s the results were as follows: When subjects did not equilibrate middle ear pressure, air conduction at low frequency tones increased more than bone conduction. The degree of deterioration in hearing was greater when the chamber pressure was increased (descent) than where pressure was decreased (ascent). When the subjects equilibrated middle ear pressure, little change in the levels of air or bone conduction was observed. Most of the deterioration in bone conduction was considered to reflect functional loss due to increased stiffness and damping of the sound transmission mechanism.

Equilibrium of inner and middle ear pressure

Global balance of inner and middle ear pressure is controlled by the cerebrospinal fluid inside and the atmospheric pressure outside. The cochlear and vestibular aqueducts and the Eustachian tube, connected by a one-way communication, provide a fine control over inner and middle ear pressure.

The influence of middle ear pressure changes on the primary vestibular neurons in guinea pigs

The responses of primary vestibular neurons and perilymphatic pressure changes to middle ear pressure stimuli in guinea pigs were investigated in order to clarify the direct effects of pressure stimulus on the vestibular apparatus. The vestibular response was related to the amount of middle ear pressure change applied at a rate of +/- 100 mmH2O/s. The neural response rates of vestibular units to positive pressure in the middle ear were significantly larger than those to negative pressure. The time course pattern of the perilymphatic pressure change resembled that of the response of the vestibular units, indicating that the vestibular response is elicited by middle ear pressure via the pressure transmitted in the inner ear.

The influence of middle ear pressure on the lateral vestibulospinal tract neurons in cats

The influence of changes in middle ear pressure on the lateral vestibulospinal tract (LVST) neurons was investigated in anesthetized cats. The activities of some LVST neurons increased with negative pressure and decreased with positive pressure. This tendency was stronger when pressure changes were applied to the contralateral middle ear than to the ipsilateral side. The influence of changes in middle ear pressure on LVST neurons was opposite to that on the vestibular nerve, suggesting the existence of inhibitory inter- and commissural neurons.

Effects of hypobaric pressure on the labyrinth. Cochlear aqueduct patent

Cats with the cochlear aqueduct patent were placed in a pressure chamber and exposed for 10 min to hypobaric pressures of 5.1 and 6.8 kPa relative to atmospheric pressure. The experiments were designed according to a program used for treatment of Meniere's disease. The perilymph, middle ear, cerebrospinal fluid (CSF), venous, arterial and chamber pressures were recorded. The results demonstrated that hypobaric effects on the labyrinth were mediated via pressure changes in the middle ear and not via a systemic vascular or CSF influence. A reduction in chamber pressure induced a relative increase in middle ear pressure. It was the rate of the hypobaric change as well as the patency of the cochlear aqueduct and the Eustachian tube function that determined the magnitude of the initial perilymph peak pressure and the duration of this pressure increase. A rapid versus a slow rate induced an initial perilymph increase of 3.4 and 2.2 kPa, respectively. This relative pressure increase was eliminated within 1 min via the patent aqueduct. Thus, neither did a longstanding perilymph pressure increase occur during the hypobaric exposure, nor did a prolonged significant reduction in perilymph pressure occur after atmospheric pressure was restored.

The influence of middle ear pressure on the vestibular nerve activity in cats

The influence of middle ear pressure on the vestibular nerve activities was investigated in anesthetized cats. The vestibular nerve activities were recorded intraaxonally and positive or negative pressure was applied to the middle ear cavity through a tympanic membrane perforation. The firing of vestibular nerve fibers, especially the regular type nerve that responded to horizontal semicircular canal stimulation, increased with positive pressure and decreased with negative pressure. Most vestibular nerves that responded to anterior or posterior semicircular canal stimulation were not influenced by changes in the middle ear pressure. These results indicate that middle ear pressure load is transmitted to the vestibular end organs and then to vestibular nerve.

A simple, effective method of treating vertigo patients

Medical treatment of vertigo even today is far from satisfactory. A controlled clinical trial of treating vertigo patients by 1% ephedrine hydrochloride nasal douche has been conducted in 84 patients; 74.3% patients were either completely or partially relieved of their dizziness. The therapy was well accepted by patients and side effects were minimal.

Transmission of square wave pressure pulses through the perilymphatic fluid in cats

The inner ear hydrodynamics have been studied in a series of experiments on cats. A detailed analysis has been made of the perilymphatic pressure response to square wave pressure pulses applied to the ear canal and middle ear. It was found that the initial pressure response was followed by a rebound pressure response of the opposite phase. It was also found that in most cases each phase of the pressure response could be expressed in terms of two time constants. When the cochlear aqueduct was patent, the perilymphatic pressure response showed almost equal positive and negative pressure changes. However, when the cochlear aqueduct was surgically blocked, the perilymphatic pressure response consisted almost exclusively of the first phase of the response, while the rebound phase disappeared almost completely. The possibility of influencing the inner ear fluid balance in Meniere's disease by external pressure changes is discussed in the light of the present experimental results.

Diving injuries

This is a collective review about the pathophysiology, diagnosis, and management of SCUBA and diving injuries by the emergency physician. These injuries can be classified into those resulting from the toxic effects of the inhaled gas, from the pressure changes in the water and gas mixture while diving, and from decompression sickness. With the increasing popularity of SCUBA diving, it is hoped that this discussion will enable a recognition of these injuries and therefore minimize the morbidity and mortality from them.

Otolaryngologic aspects of scuba diving

Among the most common injuries encountered by the 700,000 active sport scuba divers in the United States are sinus and otitic barotrauma. The management of these injuries and the identification of high-risk patients during their required pretraining physical examination are discussed.

Sudden or fluctuating hearing loss and vertigo in children due to perilymph fistula

Five cases are presented of children with rapid onset of sensorineural hearing loss, disequilibrium, or both, who were found at exploratory tympanotomy to have a perilymph fistula. Four of the children had histories suggesting that antecedent barotrauma or physical exertion contributed to the development of the fistula. One child with congenital unilateral craniosynostosis had a residual temporal bone abnormality on the same side as the perilymph fistula. Two children had identifiable anatomic abnormalities in the middle ear. A classification of perilymph fistula is proposed that describes a congenital, an acquired, and a combined type of fistula. Inner ear fluid dynamics and patency of the cochlear aqueduct appear to be important factors in pathogenesis. Children with unexplained fluctuating or sudden onset of sensorineural hearing loss, and children with unexplained disequilibrium or vertigo should be suspected of having a perilymph fistula. The history can be singularly important in raising the suspicion that a perilymph fistula may be present. Although audiometric, vestibular, and radiographic studies can be helpful, there is no way to prove the presence or absence of a fistula without directly viewing the middle ear. Tympanotomy with repair of the fistula does not assure improvement in hearing.

Diving injuries to the inner ear

Most of the previous literature concerning otologic problems in compressed gas environments has emphasized middle ear barotrauma. With recent increases in commercial, military, and sport diving to deeper depths, inner ear disturbances during these exposures have been noted more frequently. Studies of inner ear physiology and pathology during diving indicate that the causes and treatment of these problems differ depending upon the phase and type of diving. Humans exposed to simulated depths of up to 305 meters without barotrauma or decompression sickness develop transient, conductive hearing losses with no audiometric evidence of cochlear dysfunction. Transient vertigo and nystagmus during diving have been noted with caloric stimulation, resulting from the unequal entry of cold water into the external auditory canals, and with asymmetric middle ear pressure equilibration during ascent and descent (alternobaric vertigo). Equilibrium disturbances noted with nitrogen narcosis, oxygen toxicity, hypercarbia, or hypoxia appear primarily related to the effects of these conditions upon the central nervous system and not to specific vestibular end-organ dysfunction. Compression of humans in helium-oxygen at depths greater than 152.4 meters results in transient symptoms of tremor, dizziness, and nausea plus decrements in postural equilibrium and psychomotor performance, the high pressure nervous syndrome. Vestibular function studies during these conditions indicate that these problems are due to central dysfunction and not to vestibular end-organ dysfunction. Persistent inner ear injuries have been noted during several phases of diving: 1) Such injuries during compression (inner ear barotrauma) have been related to round window ruptures occurring with straining, or a Valsalva's maneuver during inadequate middle ear pressure equilibration. Divers who develop cochlear and/or vestibular symptoms during shallow diving in which decompression sickness is unlikely or during compression in deeper diving, should be placed on bed rest with head elevation and avoidance of maneuvers which result in increased cerebrospinal fluid and intralabyrinthine pressure. With no improvement in symptoms after 48 hours, exploratory tympanotomy and repair of a possible labyrinthine window fistula should be considered. Recompression therapy is contraindicated in these cases...

Cochleo-vestibular disturbances in diving

Insidious development of high-tone sensorineural hearing loss may be associated with diving, but the evidence is not certain and further research is needed. 'Internal ear barotrauma' can cause an acute or relatively acute onset of hearing loss and/or vertigo, and it may be that 'alternobaric vertigo' provides a link between the insidious and acute forms of labyrinthine injury in diving. With deep diving, decompression sickness and other syndromes can also affect the cochleo-vestibular system. These aetiologies and effects will be discussed, together with evidence from an audiometric survey of naval divers and of 5 experimental deep divers.

Treatment of the diving casualty

In a diving emergency a number of specific conditions are possible in addition to those which would ordinarily be considered in a life-threatening situation. There are many separate factors which, underwater, can lead by some unfortunate combination of circumstances towards death usually, but not always, by drowning. The other major category of accidents are those resulting from the ascent of the diver to the surface. These must be considered as medical emergencies and the majority respond to immediate recompression. In the absence of readily available recompression facilities,various measures may ameliorate the condition pending transfer to a suitable compression chamber.

[Etiology of peripheral facial paralysis. Report of an unusual case]

Após conceituar a paralisia de Bell, ressaltar sua alta incidência e expor as teorias que se propõem a explicá-la, é relatado um caso de paralisia facial periférica isolada ocorrido durante o retorno de um mergulho, em paciente de 28 anos. Na revisão bibliográfica realizada são mencionadas e discutidas numerosas entidades que têm sido consideradas como causas de paralisia facial periférica, destacando-se um trabalho americano que relata dois casos ocorridos, de forma transitória, durante aumento de altitude e que foram atribuídos à variação de pressão no ouvido médio. Como conclusão, é admitido um mecanismo similar para o caso em pauta.