Sudden sensorineural hearing loss from a Jugular Bulb Diverticulum

@#A 19-year-old woman presented with an 11-month history of sudden-onset left sided hearing loss accompanied by vertigo and headache. Audiometric testing revealed profound left- sided hearing loss. A contrast-enhanced MRI of the internal auditory canal performed 5 months after symptom onset was interpreted as showing a vascular loop, probably the anterior inferior cerebellar artery, abutting and indenting on the left vestibulocochlear nerve; and a prominent and high-riding left jugular bulb. In this study, the internal auditory canals were assessed to be of normal width, with walls that were smooth and sharply defined. A cerebral CT angiogram subsequently performed did not show any abnormal findings related to the previously identified vascular loop. On the basis of these radiologic findings, the patient was advised surgery by physicians at a tertiary- care institution, presumably to address the identified vascular loop. A second opinion was sought by the patient.

Diagnosis and management of otosclerosis in a Filipino population: A case series

Objective@#This case series aims to describe the diagnosis and management of otosclerosis in a series of Filipino patients encountered in a private, subspecialty otologic clinical practice. In particular, it elucidates the demographics, clinical presentation, diagnostic exam findings, clinical intervention and hearing outcomes.@*Methods@#Study Design : Retrospective review of medical records of a case series. Setting : Subspecialty otologic / neurotologic clinical practice. Participants : Medical records of all patients diagnosed to have otosclerosis based on radiologic evidence of fenestral or retrofenestral otosclerosis and/or confirmed during surgical exploration of the middle ear, during the period 2004-2017. @*Results@#Nine patients with otosclerosis were identified. Most patients presented with bilateral, primarily conductive hearing loss in middle age. However, an adolescent patient was also identified. Most patients were from the component cities of the National Capital Region. However, patients from the Cordillera region and south-central Mindanao were also identified. Radiologic evidence of fenestral or retrofenestral otosclerosis was identified in the majority of patients. However, readings of normal temporal bone CT findings were also seen. Obliterative otosclerosis was identified in one patient. Both objective and subjective evidence of hearing improvement was documented after stapedectomy in patients undergoing surgery.@*Conclusions@#This study documents the presence of clinical otosclerosis in a Filipino population. As in other populations, it typically presents in middle age as a bilateral, primarily conductive hearing loss. However, a younger age does not preclude its diagnosis, as juvenile otosclerosis has been identified. The presence of patients in regions of the Philippines other than the National Capital Region implies that it has to be considered even in regional populations without a racial predilection for otosclerosis. The identification of radiologic evidence of fenestral and retrofenestral otosclerosis on CT imaging of the temporal bone makes this is an essential part of the work-up of Filipino patients with conductive hearing loss and normal otologic examinations. Surgical treatment via stapes surgery is an effective and viable option in the management of Filipino patients with otosclerosis. The identification of less common variants such as obliterative otosclerosis indicates the need for specialized surgical equipment and appropriate surgical training in order to successfully deal with these situations.

Fracture of the petrous carotid canal

@#A 23-year-old male motorcyclist experienced blunt head trauma with loss of consciousness, headache and vomiting, epistaxis and right otorrhagia after a collision with a motor vehicle. Fractures involving the right parietal and temporal bones, as well as acute subdural and subarachnoid hemorrhage were identified on a cranial and facial CT scan. On independent evaluation of the imaging study, a subtle but distinct fracture line in the skull base involving the petrous carotid canal was identified. (Figure 1) The patient subsequently underwent CT angiography to evaluate for any injury to the internal carotid artery. In this examination, good opacification of the internal carotid arteries and their branches was noted, with no evident aneurysm, arteriovenous malformation or arteriovenous fistula formation. In patients with temporal bone fractures, the most commonly encountered complications are: tympano-ossicular injury causing conductive hearing loss, cochlear or vestibular injury causing sensorineural hearing loss or vertigo, facial nerve trauma causing facial paralysis, and fractures of the tegmen or posterior cranial fossa plate causing cerebrospinal fluid leaks.1 On the other hand, injury to the intratemporal portion of the internal carotid artery has been described as a rare complication and as such may be overlooked.1 However, its potentially devastating and life-threatening sequelae necessitates a purposeful and intentional evaluation for its presence. These sequelae include brain ischemia from arterial dissection or complete vascular occlusion, exsanguinating epistaxis or otorrhagia from carotid pseudoaneurysms, and the formation of carotid-cavernous fistulas.2 The incidence of involvement of the carotid canal in skull base fractures has been reported to be around 24%, with around 11% of this group developing internal carotid artery injuries.3 As such, the presence of fractures involving the petrous carotid canal is an indication for CT or MR angiography to further evaluate the internal carotid artery.

Inner ear hemorrhage : A cause of sensorineural hearing loss in leukemia

@#A 25-year-old male who was recently diagnosed with chronic myelogenous leukemia developed bilateral tinnitus and hearing loss. The hearing loss progressed rapidly but asymmetrically, with the right ear being subjectively worse than the left. Pneumatoscopy revealed bilaterally intact and mobile tympanic membranes and no visual evidence of middle ear pathology. Audiometry confirmed the presence of a profound hearing loss in the right ear and a moderate sensorineural hearing loss in the left ear. In relation to evaluating the cause of hearing loss, the radiologic interpretation of a contrast-enhanced cranial MRI performed to evaluate other neurological symptoms that predated the hearing loss only stated that the cerebellopontine angle cisterns were unremarkable. No mention was made about the status of the inner ears. When asked to comment on the inner ears in the MR study, the radiologist opined that the cranial MRI did not have the proper fine-cut imaging sequences necessary to evaluate this region adequately, and indicated the need for a dedicated MR study of the temporal bones. An independent review of the DICOM imaging data of the patient’s cranial MRI revealed the presence of three imaging sequences with information pertinent to the evaluation of the inner ears. These sequences are shown below, with a sequential narration of the descriptive imaging findings and their clinical significance that helps to arrive at a conclusive diagnosis.

Post-traumatic malleo-incudal complex dislocation

@#A 27-year-old man undergoes otolaryngologic evaluation for blunt head trauma suffered in a vehicular accident. With regards to the right ear, pertinent otologic findings include an ear canal laceration and a delayed-onset facial nerve paresis. Tuning fork testing reveals an abnormal Rinne test on the right (AC<BC). The radiologist’s interpretation of the computerized tomographic imaging study of the temporal bone indicated the presence of a longitudinal fracture of the right temporal bone with no disruption of the ossicular chain. (Figure 1) However, careful examination of the anatomy of the malleo-incudal complex in relation to the other structures in the epitympanum actually reveals findings indicative of a malleo-incudal complex dislocation. How can this discrepancy in the radiologic interpretation be accounted for? By what objective parameters can the presence of a malleoincudal complex dislocation be identified?

Fenestral otosclerosis: A subtle lesion easily missed

@#A 29-year-old Filipina of Chinese descent presented with progressive bilateral conductive hearing loss of several years’ duration. While working overseas, she consulted with an otolaryngologist and underwent computerized tomographic (CT) imaging of the temporal bone as part of her evaluation. She was informed that no abnormalities were identified in the imaging exam, and she was offered exploratory middle ear surgery with possible stapes surgery. She then sought a second opinion, with the intention of obtaining a more definitive diagnosis prior to any invasive medical intervention. A review of the CT imaging study, with particular emphasis on looking for radiologic evidence of otosclerosis, revealed the presence of a focal region of bone demineralization in the region of the fissula ante fenestram. (Figure 1) This finding is consistent with a diagnosis of fenestral otosclerosis.

Eye movement autophony: A unique presenting symptom of semicircular canal dehiscence syndrome

@#A 31-year-old woman presented with the very unusual symptom of being able to hear the movement of her eyeballs in her left ear: “I can hear my eyeballs move!” She initially described hearing a recurrent “swishing” sound that would occur intermittently. She eventually realized that its occurrence coincided with eyeball movement. In the eight months’ duration of her symptom, she had been unable to obtain a diagnosis from physicians whom she consulted and had even been referred for psychiatric evaluation and treatment. An otolaryngologist whom she consulted had a standard pure tone audiometric examination done, and this showed normal hearing acuity in both ears. A Magnetic Resonance Imaging (MRI) of the inner ear and brain likewise showed no abnormalities. Due to the peculiarity of the patient’s complaint, the otolaryngologist consulted with a neurotologist who suspected the presence of a semicircular canal dehiscence. A computerized tomographic imaging study of the temporal bone confirmed the presence of a left superior semicircular canal dehiscence syndrome.

On the importance of proper window and level settings in temporal bone CT imaging

@#During a discussion on temporal bone imaging, a group of resident trainees in otolaryngology were asked to corroborate the finding of a fracture in set of images that were supposed to be representative of a fracture involving the otic capsule.1(Figure 1) Their comments included the following statements: “The image still does not clearly identify the fracture. It would have been better if the images were set to the optimal bone window configuration...” “The windowing must be of concern as well. The exposure setting for the non-magnified view is different from the magnified ones. One must observe consistent windowing in order to assess the fractures more accurately.” “...the images which demonstrate a closer look on the otic capsule areas are not rendered in the temporal bone window which makes it difficult to assess.” “...aside from lack of standard windowing...”

Pulsatile tinnitus due to a sigmoid sinus diverticulum and/or dehiscence

@#<p style="text-align: justify;">In 2009, a 52-year-old man presented with a two year history of intermittent right-sided pulse-synchronous tinnitus. He noted that the tinnitus worsened when his blood pressure was elevated. Otologic exam was unremarkable, with no obvious middle ear fluid or mass. There was no neck bruit, and the tinnitus diminished on manual compression of the ipsilateral internal  jugular vein. In keeping with the recommendations for clinical imaging at that time, a non-contrast CT of the temporal bone was performed. This was to evaluate for conditions such as : a middle ear glomus, an aberrant internal carotid artery, a jugular bulb variant (e.g. a high-riding jugular bulb), otosclerosis, superior semicircular canal dehiscence syndrome, a persistent stapedial artery, or a hemangioma of the temporal bone.1 No evidence of these conditions was found. An MRI of the brain, with MR angiography and venography of the intracranial vasculature also performed to evaluate for conditions such as:  idiopathic intracranial hypertension, a dural arteriovenous fistula, an arteriovenous malformation, vascular loop syndrome, and dural sinus stenosis or thrombosis.2 All of these conditions were excluded. As no definite pathology was identified, no firm treatment reommendations were initiallly made.</p><p style="text-align: justify;">In 2011, Eisenman reported on a series of 13 patients with pulsatile tinnitus due to a sigmoid sinus diverticulum and/or dehiscence who were successfully treated surgically via an extraluminal transmastoid approach.3 This was the first relatively large series published in the otologic literature. This publication likewise reported on the subtle radiologic signs that signify the presence of a sigmoid sinus diverticulum and/or dehiscence, such as an irregularity of the normal semicircular contour of the bony sinus wall, focal thinning of the calvarial cortex overlying the adjacent sinus wall, absence of the normal thin layer of cortical bone overlying the sinus, and the "air-on-sinus" sign, where mastoid air cells directly contact the sinus wall, without overlying bone.3</p><p style="text-align: justify;">In light of this new information, the patient's imaging studies were re-evaluated, and evidence of a right-sided sigmoid sinus diverticulum and/or dehiscence was identified. The images below show the findings on an axial slice of the patient's temporal bone CT study.</p><p style="text-align: justify;"> </p><p style="text-align: justify;">How significant is this condition ? Sigmoid sinus diverticulum and/or dehiscence is being increasingly recognized as a common cause of pulsatile tinnitus. In fact, a recent study by Schoeff et al. found its prevalence to be 23% in patients with pulsatile tinnitus.4 As such, the identification of this condition is highly relevant, particularly because effective surgical management is available for its alleviation.</p>

Genetic polymorphisms in NAT1, NAT2, GSTM1, GSTP1 and GSTT1 and susceptibility to colorectal cancer among Filipinos

@#Objectives. Polymorphisms in metabolic genes which alter rates of bioactivation and detoxification have been shown to modulate susceptibility to colorectal cancer. This study sought to evaluate the colorectal cancer risk from environmental factors and to do polymorphism studies on genes that code for Phase I and II xenobiotic metabolic enzymes among Filipino colorectal cancer patients and matched controls. Methods. A total of 224 colorectal cancer cases and 276 controls from the Filipino population were genotyped for selected polymorphisms in GSTM1, GSTP1, GSTT1, NAT1 and NAT2. Medical and diet histories, occupational exposure and demographic data were also collected for all subject participants.Results. Univariate logistic regression of non-genetic factors identified exposure to UV (sunlight) (OR 1.99, 95% CI: 1.16-3.39) and wood dust (OR 2.66, 95% CI: 1.21-5.83) and moldy food exposure (OR 1.61, 95% CI:1.11-2.35) as risk factors; while the NAT2*6B allele (recessive model OR 1.51, 95% CI :1.06-2.16; dominant model OR 1.87, 95% CI: 1.05-3.33) and homozygous genotype (OR 2.19, 95% CI: 1.19-4.03) were found to be significant among the genetic factors. After multivariate logistic regression of both environmental and genetic factors, only UV radiation exposure (OR 2.08, 95% CI: 1.21-3.58) and wood dust exposure (OR 2.08, 95% CI: 0.95-5.30) remained to be significantly associated with increasing colorectal cancer risk in the study population.Conclusion. This study demonstrated that UV sunlight and wood dust exposure play a greater role in influencing colorectal cancer susceptibility than genotype status from genetic polymorphisms of the GST and the NAT` genes.

Unilateral horizontal semicircular canal malformation causing recurrent vertigo

@#A 62-year-old man consulted for recurrent episodes of vertigo lasting from seconds to several minutes. The vertigo was variably described as spinning, lateral swaying, and a feeling of being “unsure of his position in space.” These episodes were noted to have begun when the patient was still in his 20’s. Standard pure tone audiometry revealed a mild-to-moderate downsloping mixed hearing loss in the left ear. Bithermal caloric testing indicated the presence of a significant left-sided peripheral vestibular loss. Due to the fact that the vertigo episodes presented relatively early in life, the possibility of a congenital inner ear malformation was considered as a cause for his symptoms. Computerized tomographic (CT) imaging of the temporal bone was performed. This clearly showed the left horizontal semicircular canal lacking a central bony island. (Figure 1 and 2) The cochlea, superior and posterior semicircular canals, vestibular and cochlear aqueducts, and ossicular chain were grossly normal. A malformation of the horizontal or lateral semicircular canal is one of the most common inner ear malformations, as it is the last vestibular structure to be formed during inner ear embryogenesis. As such, it may occur in isolation or may be associated with other vestibular, cochlear, or middle ear malformations.1,2 Although vertigo and dizziness are symptoms to be expected in such a condition, existing data indicates that it may be totally asymptomatic, or it may also present as a sensorineural, conductive, or mixed type of hearing loss.1,3 Radiologic imaging is of prime importance in diagnosing such conditions, especially when auditory and/or vestibular symptoms manifest early in life. This case perfectly illustrates the need for such studies, as the patient went undiagnosed for more than forty years! No definitive statements can be gleaned from existing medical literature with respect to treatment. However, in patients with debilitating vestibular symptoms, management with modalities that selectively target the vestibular system, but spare the auditory system, such as vestibular neurectomy and trans-tympanic aminoglycoside therapy appear to be reasonable options.

Spontaneous middle fossa encephalocele

@#A 48-year old man presented with a unilateral right hearing loss of four months’ duration. A right middle ear effusion was noted on physical examination. Endoscopic examination of the nasopharynx was unremarkable. Due to the duration of the symptoms, myringotomy with ventilation tube insertion was offered as a treatment option. Upon myringotomy, clear pulsatile liquid flowed out of the incision. More than 5 cc of liquid was collected which continued to flow out despite active suctioning. Due to the realization that the liquid most likely represented cerebrospinal fluid, insertion of a ventilation tube was not performed. The ear canal was packed with sterile cotton, and the patient was given a short course of acetazolamide to decrease CSF production. Upon further questioning, the patient did not have any prior head trauma. The patient then underwent both computerized tomographic (CT) imaging and magnetic resonance imaging (MRI) of the temporal bone to look specifically for evidence of a dehiscence in the middle fossa plate (tegmen) or posterior fossa plate, as well as the presence of a meningoencephalocele.

Meningioma in the middle ear: An unusual case of hearing loss

@#<p style="text-align: justify;">When evaluating patients presenting with progressive unilateral hearing loss without a history of trauma or infection, it is important consider the clinical correlation of physical examination findings, imaging and audiograms. It is crucial that all findings are correctly reviewed and analyzed to provide an accurate assessment and appropriate management for the patient.</p>

Ossicular erosion from a posterior pars tensa retraction cholesteatoma

@#A 14-year old female with Down syndrome presented with a 3-year history of recurrent purulent left otorrhea. The discharge had become more frequently blood-tinged. Otologic examination revealed a stenotic ear canal with polypoid granulation obstructing the view of the tympanic membrane. High resolution computerized tomographic (HRCT) imaging of the temporal bone was performed to assess the status of the middle ear and mastoid. Particular attention was given to assess for bony erosion associated with cholesteatoma formation.

When is a vestibular aqueduct enlarged?

@#A ten-year-old boy with bilateral moderate sensorineural hearing loss underwent computerized tomographic (CT) imaging (GE Brightspeed, Wisconsin, USA) of the temporal bone as part of the work-up to determine the etiology of his condition. The formal radiologic interpretation of the scan stated that the vestibular aqueducts were not enlarged. However, independent review of the axial CT images appeared to indicate the presence of enlarged vestibular aqueducts. (Figure 1) This can be contrasted with a scan from another patient with no evidence of sensorineural hearing loss. (Figure 2) What can explain the discrepancy between the two? If simple visual inspection of the vestibular aqueduct (VA) can lead to conflicting interpretations, then what radiographic parameters can be used to resolve the issue? Is there a more objective means of determining the presence of a clinically significant vestibular aqueduct enlargement? In 1978, Valvasorri and Clemis1 first described an association between congenital sensorineural hearing loss and an abnormality in vestibular aqueduct anatomy which they labelled as the “large vestibular aqueduct syndrome.” In this landmark study that utilized hypocycloidal polytomographic temporal bone studies, they proposed that a vestibular aqueduct is enlarged when its midpoint diameter is greater than 1.5 mm. Although this parameter is generally considered to be the defining characteristic of the condition, one must realize that this measurement was based on less accurate imaging technology and measurement tools. Contemporary studies utilize high-resolution CT imaging with digital workstation measurement software to evaluate vestibular aqueduct anatomy. Currently, the two most commonly used radiographic parameters are the VA midpoint (MP) width and the VA opercular (OP) width. (Figure 3) More recently, Boston et al.2 in 2007 published normative values for these parameters based on a study population of 73 children without known sensorineural hearing loss. They considered a vestibular aqueduct enlarged when one or both of the measured widths were above the 95th percentile of the normal study group measurements. On this basis, a VA midpoint width of >0.9 mm and/or a VA opercular width of >1.9 mm was the criteria established to define an enlarged vestibular aqueduct. The patient’s measured vestibular aqueduct midpoint width on the right was 2.1 mm, while the vestibular aqueduct opercular width was 2.9 mm. (Figure 4) These measurements, when evaluated against either the original Valvassori criteria or the newer criteria of Boston et al., confirm what was visually apparent– the presence of a clinically significant enlargement of the vestibular aqueduct as the etiology of the patient’s sensorineural hearing loss.

Technique of multi-planar CT image reconstruction for the evaluation of superior semicircular canal dehiscence syndrome

@#Superior semicircular canal dehiscence (SSCD) syndrome is an unusual cause of vertigo that was first identified by Minor in 1998. The patients initially described by Minor presented with vertigo, oscillopsia and/or dysequilibrium related to sound, changes in middle ear pressure and/or changes in intracranial pressure due to an absence of the bony layer that normally covers the superior semicircular canal.1Subsequent clinical studies have shown that the condition may lead to a variety of vestibular and/or auditory symptoms that mimic other otologic disorders. These symptoms include autophony, ear blockage or fullness, conductive hearing loss, pulsatile tinnitus, dizziness or vertigo with head movements and general disequilibrium.

Superior semicircular canal dehiscence syndrome: Review of clinical manifestations in adults and children

Objective: This report aims to determine the clinical manifestations and management of patients with superior semicircular canal dehiscence syndrome (SSCDS). Methods: Design: Case series Setting: Tertiary hospitals and private clinics Participants: Out of 30 patients with vestibular vertigo or otologic symptoms, 14 patients were diagnosed with SSCDS based on high resolution computed tomographic scan (HRCT). The demographic features, incidence of specific signs and symptoms and management of these patients were described, including the audiograms, vestibular evoked myogenic potential (VEMP) responses and ancillary tests. Results: Vertigo was the most common vestibular symptom of SSCDS. Tullio phenomenon was elicited in 50% of patients with confirmed dehiscence on HRCT scan. Low frequency (250 Hz and 500 Hz) air-bone gap was noted in 21.4% of patients. Lowered VEMP responses were also noted in 66.7% of patients with confirmed SSCDS. Severity of symptoms may determine its management. Conclusion: The diagnosis of SSCDS does not conform to a specific clinical presentation or audiologic result and good clinical correlation is needed in order to raise suspicion of the disease and prompt the clinician to order confirmatory imaging by computed tomographic scan or magnetic resonance imaging. The presence of this syndrome in a proportion of children that is greater than previously reported needs further study as these children may be genetically predisposed to have thinned out superior semicircular canals that eventually become dehisced albeit at an earlier age.