Histopathological basis of hearing impairment in Wolf-Hirschhorn syndrome

OBJECTIVES/HYPOTHESIS: To perform histological examination of temporal bones acquired from an infant with Wolf-Hirschhorn syndrome with an emphasis on identifying abnormalities that might be responsible for hearing impairment in this disorder. STUDY DESIGN: Retrospective case review. METHODS: Temporal bones were taken at autopsy from a 10-month-old infant with Wolf-Hirschhorn syndrome. The right-side temporal bone was studied by microdissection. The middle ear was examined, and the inner ear sensory organs dissected for study by light microscopy. The left-side temporal bone was embedded in celloidin, and sections were cut for microscopic examination. RESULTS: Chronic otitis media was observed in both ears. Inflammation, effusion, and adhesions were present in the middle ear space. The malleus was malformed, and the chorda tympani nerve was found to pass through the bone of the malleus bilaterally. There was an area of sharply defined outer hair cell loss in the lower basal turn of the right-side organ of Corti, and defects were noted in the bone of the apical osseous spiral lamina in both cochleae. CONCLUSION: In addition to the presence of otitis media, the likelihood of congenital abnormalities of the middle and inner ear should be considered in the assessment of patients with Wolf-Hirschhorn syndrome with hearing impairment.     

Frequency and localization of congenital anomalies of the middle and inner ears: a human temporal bone histopathological study

This study investigated congenital anomalies occurring in the middle and the inner ears, with particular attention to their features, localizations, and frequencies. One hundred human temporal bones obtained from 73 individuals, aged 31 gestational weeks to 39 years, each of whom had anomalies of the middle ear and/or inner ear, were used for this study. The temporal bones had been removed at autopsy, fixed, dehydrated, embedded in celloidin, and sectioned horizontally or vertically at 20 microns. Every 10th horizontal section or every 20th vertical section was stained with hematoxylin and eosin, mounted and studied under a light microscope. In the middle ear the structure most often found to be anomalous was the facial nerve; in the inner ear it was the lateral semicircular canal. The implications of the anomalies observed are discussed as they relate to fetal development, dysfunction of the ear, and clinical interpretation of diagnostic radiological studies.     

New patterns in genetic and congenital otonephropathies

In a series of chronic renal and congenitally deaf patients 24 were identified as having inborn renal and otologic disease. Sixteen patients, representing 14 families, had genetic disorders. Only two had the features of Alport's syndrome. The patients were classified as follows: 1) Probable Alport's — 2 patients (1 family); 2) Atypical hereditary nephritis and sensorineural hearing loss — 7 patients; 3) Renal and inner ear anomalies — 1 patient; 4) Renal, inner ear and multiple anomalies — 4 patients. The temporal bone pathology in one case showed primary neural atrophy and a mild Mondini malformation. In another a Scheibe defect and unusual calcific structures were found in the cochlear duct. 5) Renal, external or middle ear and multiple anomalies — 6 patients (5 families); 6) Renal, middle and inner ear anomalies and multiple anomalies — 2 patients. A temporal bone obtained from one case showed combined middle and inner ear defects. In the other, who had a chromosome defect, predominantly middle ear anomalies were found. 7) Nephrotic syndrome and congenital hearing loss — 1 patient; 8) Unclassified — 1 patient. Some cases represent entities apparently not previously described. Probably most interesting is the delineation of hereditary nephritis and deafness distinct from Alport's disease.     

Congenital malformations of middle and inner ears of parabiotic twins

We describe herein the congenital malformations of the middle and inner ears in temporal bones of parabiotic, monozygotic twins. Temporal bones were removed from twin B, who had no fetal cardiac activity and was born dead at 23-4/7 weeks, and twin A, the donor or "pump" twin in intrauterine life, who died shortly after birth at 20-6/7 weeks. The temporal bones were processed routinely in celoidin, stained with hematoxylin and eosin, and examined by light microscopy. We found that twin B had Mondini's dysplasia with associated deformities of the middle ear and in general showed more developmental anomalies than twin A, and we conclude that Mondini's dysplasia with anomalies of the middle ear may occur in the parabiotic twin syndrome, and the abnormalities may be explainable as the result of vascular disturbance, which also causes other lesions in these unusual cases.     

Temporal bone histopathologic findings in Down's syndrome

We report the results of a histopathologic study of 12 temporal bones from seven patients with Down's syndrome and of a dimensional study of the cochlea and the vestibular apparatuses of most of these specimens. Histopathologic study disclosed numerous abnormalities of the middle ear but only a limited number of inner ear abnormalities. The dimensional study showed that, while in the majority of cases the cochlea was shortened, most of the vestibular measurements were within the normal range. We also discuss hearing loss in patients with Down's syndrome and present our hypothesis that remnants of mesenchymal tissue in the round window niche might cause a certain degree of conductive hearing loss in such cases.     

Down's syndrome: A modern otorhinolaryngological perspective

The incidence of Down's syndrome is estimated at 1.5 per 1000 births, or 7,000 newborns annually in this country. Mounting financial considerations in the delivery of medical care, as well as humanitarian considerations, fostered this in-depth prospective, multidisciplinary study. One hundred and seven patients comprised the initial group, and 83 met the criteria established for documentation of otorhinolaryngological parameters. All patients were home based and given scheduled, routine pediatric care. Otolaryngology care, when indicated, was by consultation. The uniqueness of this study exists in the fact that children were followed from the first year of life, in what must be considered an enhanced environmental setting for Down's syndrome patients. Otologic, rhinologic and laryngologic parameters were explored in-depth with the following resultant data. Patients with stenotic ear canals had a markedly increased incidence of associated middle ear effusion. In addition, patients with an increased frequency of upper respiratory tract infections in association with stenotic canals had an even greater incidence of effusion. When stenotic canals were present, the diagnosis of fluid proved difficult for the primary care physician. The total incidence of conductive middle ear pathology was shown to be significantly lower than in most reported studies. Equally important was the fact that at the time of data computation, none of the children had active, chronic middle ear pathology and cholesteatoma had not been identified. Adenoidectomy was shown clinically to have little apparent effect on the course of otologic pathology, nasal respiration or rhinorrhea in Down's syndrome. Previously unreported surgical correlates of the nasopharyngeal anatomy were related to upper respiratory obstructive symptoms manifest by many of these children. Apparent, spontaneous resolution of the latter, in most instances with age, correlated well with anticipated changes in the growth of the involved structures. Low dose antibiotic therapy was shown to be of benefit in controlling early rhinorrhea. Isolated congenital abnormalities of the lower respiratory tract were discussed with the findings that symptoms related to the respiratory tract must not be assumed to be inherent to the syndrome until other potential etiologies have been thoroughly considered. Factors relating to intelligence in Down's syndrome were explored with the conclusion that a direct and favorable comparison could be made in this study between improved hearing and improved intellect.     

Lambs' temporal bone anatomy under didactic aspects

Human temporal bones in teaching ear surgery are rare. The lamb's temporal bone might be a possible alternative.Material and Methods: Temporal bones of the lamb were dissected with a typical temporal bone lab drilling program. We included a mastoidectomy, endaural approaches, but also analyzed the outer appearance, the external ear canal and the hypotympanon. Some steps differed from preparation done in humans. The morphometric results were compared to the known anatomy of human in order to verify the lambs' temporal bone for suitability in otosurgic training.Results: The lambs' temporal bone appears smaller than the human one. We found a bullous extended hypotympanon located under the external ear canal. The tympanic membrane is very similar to the human one. The external ear canal is smaller and shorter. The ossicular chain shows analogies to human one.Discussion: This study shows, that especially the middle ear, the tympanic membrane and the external ear canal are morphologically equal to the structures found in human temporal bones. The lamb seems feasible for teaching the anatomy of the ear. The smaller scales of some structures, especially the outer components of the temporal bone are a disadvantage.Conclusions: The lamb seems to be an alternative in teaching ear surgery.     

Systemic vasculitis: A temporal bone histopathologic study

Systemic vasculitis includes a broad spectrum of disorders that may involve blood vessels of any size in any organ system. Systemic vasculitis is associated with immunopathogenic mechanisms. Sixteen temporal bones from eight persons were studied to determine histopathologic changes that occur in systemic vasculitis. Three persons had Wegener's granulomatosis, two had polyarteritis nodosa, and three had systemic lupus erythematosus. Otitis media was seen in 15 ears, with ten ears showing chronic middle ear changes and two showing fibrotic inner ear changes. In Wegener's granulomatosis, granulation tissue was observed around the eustachian tube and protympanum, and in polyarteritis nodosa, inflammatory cell infiltrate and thickened blood vessels were observed around the facial nerve. Although sensorineural hearing loss has been described clinically in systemic lupus erythematosus, the present report describes findings in temporal bones, including severe fibrosis and new bone formation throughout the inner ear.     

Temporal bone histopathologic findings in partial trisomy 13 and partial trisomy 14

OBJECTIVE: To describe temporal bone histopathology in an infant with partial trisomies of chromosomes 13 and 14. METHODS: Temporal bones were taken at autopsy from a 7-day-old neonate who has both partial trisomy 13 and partial trisomy 14. The right temporal bone was embedded in celloidin and sections were cut for microscopic examination. The left temporal bone was studied by microdissection. The middle ear was examined and the inner ear sensory organs dissected for study by light microscopy. RESULTS: The external auditory canal was stenotic in both ears. Remnants of mesenchymal tissue were present in the middle ear cavity. The middle ear ossicles were normal except that both stapes were malformed with a single crus and a small footplate. Both facial nerve canals were dehiscent in the region of the oval window. The cochlea was malformed bilaterally; a scala communis was present and the basilar membrane was abnormally short. No loss of sensory cells was observed in either cochlea. Blood vessels were found traversing scala vestibuli and there were cystic lesions in the stria vascularis and spiral ligament. In the middle cochlear turn, the bony wall of scala vestibuli and the osseous spiral lamina were covered by a substantial layer of connective tissue which appeared to be an extension of the spiral ligament. This is an unusual finding which, to the authors' knowledge, has not been previously reported. In the vestibular apparatus a wide communication was present between the saccule and utricle. CONCLUSIONS: As this study demonstrates, abnormalities of the external, middle, and inner ear may occur in cases of partial trisomy 13 and partial trisomy 14. Both temporal bone findings and clinical features in partial trisomy 13 and partial trisomy 14 to some degree overlap with those of trisomy 13, partial trisomy 13 and partial trisomy 14.     

The caloric stimulus: temperature generation within the temporal bone

Temperature measurements were performed on isolated cadaveric temporal bones subjected to caloric irrigation of the external meatus. This was undertaken in an attempt to clarify the pathways of heat transfer involved in thermal stimulation of the temporal bone. On average, the maximum temperature change produced across the lateral semicircular canal was 0.47°C, occurring 74 s after the start of the 30-s irrigation. Temperature changes of approximately 1.5°C were found to occur in the air of the middle ear cleft, indicating significant heat transfer by the process of natural convection. By comparison, removal of the bony ridge joining the external meatus with the inner ear had little effect on the temperature generated across the lateral semicircular canal. It is therefore considered that natural convection within the middle ear cleft plays an important role in caloric stimulation of the vestibular labyrinth. This view is supported by the observation that there is a lack of a direct solid connection between the outer ear and lateral limb of the lateral semicircular canal.     

Dehiscence of bone overlying the superior semicircular canal as a cause of an air-bone gap on audiometry: a case study

Dehiscence of bone overlying the superior semicircular canal can result in a syndrome of vertigo and oscillopsia induced by loud noises or by maneuvers that change middle ear or intracranial pressure. Patients with this disorder can also experience a heightened sensitivity to bone-conducted sounds in the presence of normal middle ear function. High-resolution CT scans of the temporal bones demonstrate the dehiscence. The authors describe a patient with bilateral superior canal dehiscence who had bilateral low-frequency conductive hearing loss, normal middle ear function, intact acoustic reflexes, and intact vestibular-evoked myogenic potentials. These findings would not be expected on the basis of a middle ear cause of the conductive hearing loss. A high-resolution CT scan of the temporal bones in this patient revealed bilateral superior canal dehiscence. Normal acoustic immittance findings in the presence of conductive hearing loss should alert clinicians to the possibility of inner ear cause of an air-bone gap due to superior canal dehiscence.     

Temporal bone histopathologic findings in Alagille's syndrome

Six temporal bones obtained from four individuals with Alagille's syndrome, aged 4 months and 3, 6, and 7 years, were studied histopathologically. The external auditory canals and tympanic membranes were normal. Although the stapes, the interossicular joints, and the subarcuate fossae were slightly underdeveloped in the majority of cases, the other structures in the middle ear were almost normal. However, severe anomalies were observed in structures in the inner ear. In all cases, both the bony and membranous structures of the posterior semicircular canal were partially or totally absent, and, in three ears, those of the anterior semicircular canal were also partially absent; the lateral semicircular canal, however, was normal in all cases. The cochlea was observed to be shortened in only one case.     

Congenital cholesteatomata with other anomalies.

Congenital (primary) cholesteatomata may arise in the petrous apex, mastoid, middle ear, or external auditory canal. Histological studies of the temporal bones of a 20-year old man with bilateral combined deafness show bilateral congenital cholesteatomata of the middle ears associated with dalivary choristomata and other anomalies of the middle and inner ears.     

Thickness of the migratory epithelium of the external auditory canal

The migratory epithelium of the external ear has been the object of much study, and it has long been presumed to thicken in abnormal conditions of the external ear. In this study, normal values have been established for the thickness of the epithelium at various sites on horizontally sectioned normal temporal bones. Three sites, the umbo, the anterior annulus, and the posterior annulus are shown to have statistically significant thickening when compared with other contiguous sites on the same section. A study of temporal bones with various abnormalities of both external and middle ear showed a statistically significant thickening of the epithelium when compared with the normal bones. This difference was particularly marked at the umbo, anterior annulus, and posterior annulus. This would imply that these thickened areas may represent growth centers in the epithelium of the external ear.     

Otologic manifestations of the hydantoin syndrome

The temporal bones of a newborn infant with hydantoin syndrome showed multiple middle ear and inner ear anomalies. There was a constellation of bony and membranous defects involving the oval and round windows, cochlear ducts, cochlear aqueducts, endolymphatic ducts and sacs, and vestibular labyrinths. To the authors' knowledge, supernumerary vestibular sensory epithelial structures and an inner ear epidermoid cyst have not been previously reported. Wide communications between the subarachnoid space and inner ear were of surgical relevance.     

The pathology of silent otitis media: A predecessor to tympanogenic meningitis in infants

Objective

To determine the association of bacteria embedded within a fibrous matrix in the middle and inner ear in infants with tympanogenic meningitis.

Methods

Thirty-one cases with meningitis from the human temporal bone collection at the University of Minnesota were screened to select those with tympanogenic meningitis. Inclusion criteria for tympanogenic meningitis were acute meningitis with histopathological evidence of chronic otitis media, and no other source of infection. The presence of labyrinthitis and pathologic changes such as granulation tissue, fibrosis, cholesterol granuloma, cholesteatoma, tympanic membrane perforation, tympanosclerosis, and the type of effusion were noted. The extent and location of bacteria embedded in a fibrous matrix were also explored.

Results

Seventeen temporal bones, from nine cases that included two females and seven males, ranging in age from five to twenty-three months, met our criteria of tympanogenic meningitis. Eighty two percent of these temporal bones had bacteria within the fibrous matrices (BFM). BFM were located in one anatomical region in one temporal bone and multiple anatomic regions in sixteen temporal bones. The most common locations were the areas near the oval and round windows. They were also commonly seen in the epitympanum, facial recess, and supratubal recess. BFM within the inner ear were observed in the scala tympani and modiolus in the middle and basal turns of the cochleae of nine temporal bones. In one of these temporal bones, BFM were seen in the internal auditory canal. Labyrinthitis was seen in all ears. The tympanic membrane was intact in all cases. BFM were not seen in three temporal bones from two patients. In one case only one side was available for study.

Conclusions

Our findings show an association between the presence of BFM in the ear with chronic pathologic changes and tympanogenic meningitis. Potential pathways of bacteria from the middle ear include hematogeous spread and/or direct spread to dura through the tympanic tegmen, and/or to the inner ear through the oval and round windows, and from there to the modiolus and the meninges. Chronic pathologic changes in the middle ear behind an intact tympanic membrane and the lack of ear symptoms may result in potentially serious sequelae and complications in infant age groups. There should be a heightened awareness of this condition.     

Ototoxicity of Vasocidin drops applied to the chinchilla middle ear

Some widely used ototopical preparations are potentially toxic to the middle and inner ear. Vasocidin Ophthalmic Solution (sulfacetamide sodium and prednisolone sodium phosphate) has been advocated as an alternative agent that may have fewer toxic side effects in the treatment of otorrhea. Vasocidin was introduced into the bullae of nine chinchillas to investigate the effects on the middle and inner ear. The organ of Corti and stria vascularis were found to be entirely normal in 17 of the 18 temporal bones studied. Changes observed in the middle ears at one week included inflammation, hemorrhage, and effusion. Examination of specimens at four weeks revealed resolution of most of the inflammatory changes. The results of this experimental study indicate that Vasocidin causes reversible middle ear inflammation with little or no toxic effect on inner ear structures.     

Ear abnormalities in patients with oculo-auriculo-vertebral spectrum (Goldenhar syndrome)

Oculo-auriculo-vertebral spectrum (OAVS) is a rare condition characterized by the involvement of the first branchial arches.PurposeTo investigate the ear abnormalities of a sample of patients with OAVS.Materials and methodsThe sample consisted of 12 patients with OAVS seen at the Clinical Genetics Unit, UFCSPA/CHSCPA. The study included only patients who underwent mastoid computed tomography and with normal karyotype. We performed a review of its clinical features, giving emphasis to the ear findings.ResultsNine patients were male, the ages ranged from 1 day to 17 years. Ear abnormalities were observed in all patients and involved the external (n=12), middle (n=10) and inner ear (n=3). Microtia was the most frequent finding (n=12). The most common abnormalities of the middle ear were: opacification (n=2), displacement (n=2) and malformation of the ossicular chain. Agenesis of the internal auditory canal (n=2) was the most frequent alteration of the inner ear.ConclusionsEar abnormalities are variable in patients with OAVS and often there is no correlation between findings in the external, middle and inner ear. The evaluation of these structures is important in the management of individuals with OAVS.     

Sleep Apnea and Down's Syndrome

Objective—Obstructive sleep apnea has been reported to occur in 20–50% of children with Down's syndrome in case series of patients referred for evaluation of suspected sleep apnea. In this population-based controlled study, we aimed to investigate whether sleep apnea is related to Down's syndrome.

Material and Methods—Every child aged 2–10 years with Down's syndrome residing in the Umeå healthcare district (n = 28) was invited to participate in the study, with their siblings acting as controls. Successful overnight sleep apnea recordings and echocardiography were performed in 17/21 children with Down's syndrome and in 21 controls.

Results—Obstructive sleep apnea could not be diagnosed, either in children with Down's syndrome or in the control children. The apnea-hypopnea index in the children with Down's syndrome was 1.2 ± 1.5 and did not differ from that in controls. Snoring and hypertrophy of the tonsils were more common in children with Down's syndrome than in controls. Children with Down's syndrome slept for a shorter time (p < 0.001) and changed body position more often (p < 0.05) than the control children.

Conclusions—Snoring, restless sleep and hypertrophy of the tonsils were common among children with Down's syndrome. Obstructive sleep apnea was, however, not related to Down's syndrome in the present population-based controlled study.