Michael M. Paparella

Meniere's disease

Menieres disease is a chronic illness that affects a substantial number of patients every year worldwide. The disease is characterised by intermittent episodes of vertigo lasting from minutes to hours, with fluctuating sensorineural hearing loss, tinnitus, and aural pressure. Although there is currently no cure, more than 85% of patients with Menieres disease are helped by either changes in lifestyle and medical treatment, or minimally invasive surgical procedures such as intratympanic steroid therapy, intratympanic gentamicin therapy, and endolymphatic sac surgery. Vestibular neurectomy has a very high rate of vertigo control and is available for patients with good hearing who have failed all other treatments. Labyrinthectomy is undertaken as a last resort and is best reserved for patients with unilateral disease and deafness.

Pathology of Sensorineural Hearing Loss in Otitis Media

The fine structure of the round window membrane has been described by Kawabata and Paparella.9 The membrane has three layers: 1) the epithelial layer, consisting of nonciliated flat cells contiguous with the middle ear lining; 2 ) the middle layer (immediately beneath the basement membrane of the epithelial layer), in which fibrocytes with extensions form a network of continuous cells with large intercellular spaces filled with collagen and elastic ---fibers; and 3) the inner layer (facing the scala tympani) consisting of elongated thin cells with thin cytoplasmic cxtensions (Fig. 1). The membrane measures approximately .065 nim in thickness.G

Sensorineural Hearing Loss in Otitis Media

Additional evidence is presented to support the hypothesis that both acute purulent otitis media (POM) and chronic suppurative otitis media (COM) can cause high frequency sensorineural hearing loss. In selected patients and in animals (chinchillas) in a pilot study using electrophysiological methods, both temporary threshold shifts and permanent threshold shifts of basal cochlear turn involvement were demonstrated in POM. Data of cochlear involvement in 475 ears with bilateral COM, 607 ears with unilateral COM, and 607 ears serving as controls were obtained from six centers in five countries. In group 1 (15 dB or greater), 43% of ears with unilateral COM and 42% of ears with bilateral COM showed losses, for a combined odds ratio eight times that in controls. In group 2 (30 dB or greater), 16% of ears with unilateral COM and 17% of ears with bilateral COM demonstrated, respectively, seven and ten times that in controls. These statistically significant findings influence clinical considerations.

The pathology of suppurative labyrinthitis.

A discussion of labyrinthitis seems, at first glance, a resurrection of a somewhat outdated topic, since so much was written on this subject in earlier years (especially by Europeans) and so little in recent years. Although antibiotics have curtailed its incidence, labyrinthitis is still a relatively common and clinically important inner ear disorder. A re-evaluation of the pathogenesis and pathology of suppurative labyrinthitis can provide an improved understanding of this disorder, as well as certain other labyrinthine disorders which do not manifest such discernible pathological changes.

Cellular Events Involved in Middle Ear Fluid Production

Inflammation of the middle ear and mastoid can result in fluid which is serous, mucoid, bloody, purulent or a combination of the above. Middle ear fluid problems are more common in children. That some of these problems in children can become refractory and lead to complications, including chronic granulomatous otitis media and mastoiditis, seems to be a valid clinical observation. This suggests that predisposing underlying factors for middle ear fluid problems and certain forms of chronic inflammatory mastoid disease exist as common denominators for both entities.

Pathology of Chronic Otitis Media

A review of 800 pathological temporal bones collected from autopsy cases revealed 333 (41.6%) to have some type of otitis media; purulent otitis media (52.5%), serous otitis media (6%), mucoid otitis media (4.5%), and chronic otitis media (36.9%). The 123 temporal bones with chronic otitis media were further studied and found to have granulation tissue, cholesteatoma, cholesterin granuloma, bone changes, and fibrosis. Other findings included tympanic membrane perforation, tympanosclerosis, metaplasia of the epithelium with subepithelial glandular formation, suppuration, labyrinthitis, and evidence of complications of chronic otitis media (meningitis, subdural abscess, brain abscess, petrositis, and endolymphatic hydrops). From this study it was concluded: 1) chronic otitis media occurred quite frequently, from a histological standpoint, in the absence of tympanic membrane perforation; 2) granulation tissue in temporal bones was found much more frequently in chronic otitis media than was cholesteatoma; and 3) complications and sequelae of otitis media tended to occur more commonly secondary to granulation tissue than to cholesteatoma.

Pathogenesis of Otitis Media

Pathogenesis of otitis media was studied in humans and various animal models primarily from a pathological and chemical point of view. Findings were correlated and interpreted for various forms of otitis media in longitudinal and parallel studies, including acute purulent otitis media (POM), serous otitis media (SOM), mucoid or secretory otitis media (MOM), and chronic suppurative otitis media (COM), especially as regards the continuum or interrelated changes of various groups. Purulent otitis media was produced in chinchillas by direct inoculation of less than 100 pneumococci into the middle ear space. Serous otitis media was produced in chinchillas and cats following Eustachian tube obstruction with silicone. Mucoid otitis media followed the development of SOM in cats after two to four weeks of tubal occlusion. Samples of middle ear effusion (MEE) and serum, obtained from children with SOM and MOM after myringotomy for ventilation tube placement, were evaluated. The three components studied were MEE, epithelium and the subepithelial space (SES). Inflammatory changes in the SES were significant for all forms of otitis media, but especially for POM and SOM. Epithelial metaplasia to secretory cells was most prominent in MOM. Chemical factors involved in pathogenesis and defense were studied. Lactic dehydrogenase and lysozyme, chemical indicators of inflammatory activity, were greater in POM and MOM than in SOM. Immunoglobulins (A, G, & M) were greater in MOM than in SOM. The similarity of findings between the groups suggests a strong relationship between them. The ability of certain types of otitis media to evolve into another substantiates the concept of the continuum for some patients. Pathogenesis is dependent upon various extrinsic factors of etiopathogenesis, while the form that otitis media takes seems to rely mostly on relative activity of the SES and the epithelium.

Silent otitis media

There is a traditional view that chronic otitis media and chronic mastoiditis must exist in the presence of a tympanic membrane perforation. Based on a human histopathological study of 123 temporal bones with chronic otitis media out of 333 temporal bones with all forms of otitis media pathology, only 24 patients (36 ears) had symptoms of otological disease recorded on their charts and only 19.5% of these had an associated tympanic membrane perforation. Unsuspected findings of chronic otitis media (active or inactive) are occasionally confirmed at exploratory tympanotomy. Such quiet chronic pathological findings in the middle ear have occurred in association with endolymphatic hydrops and cochlear end organ lesions suggesting the possibility that silent chronic otitis media may help explain sensorineural hearing loss, vertigo, and tinnitus for certain patients.

Prevalence of facial canal dehiscence and of persistent stapedial artery in the human middle ear: a report of 1000 temporal bones.

A total of 1000 temporal bones were used to study the prevalence of facial canal dehiscence and of persistent stapedial artery in detail. Of the temporal bones studied, 560 (56%) contained at least one facial canal dehiscence. There was a 76.3% prevalence of bilaterality of this canal wall gap. The most common site of dehiscence was the oval window area. The concept of microdehiscence of the facial canal is introduced. One third of the temporal bones observed had a microdehiscence of the facial canal, usually located at the oval window area (74.9%) and found bilaterally 40% of the time. The authors found a 0.48% prevalence (5 out of 1045) of persistent stapedial artery. This is the first histological study of temporal bones to report a prevalence of this vascular anomaly.

Otological manifestations of leukemia.

The authors have been fortunate to study the currently largest single series of temporal bones from patients with various forms of leukemia, including the first reported cases of erythroleukemia. Histologically, the middle ear showed leukemic infiltration and/or hemorrhage much more frequently than did the inner ear or external auditory canal. No sound relationship exists between the anatomical location of hemorrhage in the temporal bone and clinical otological symptomatology. A better relationship exists between the anatomical site of leukemic infiltration of the temporal bone and clinical otological symptomatology. Twenty percent of these patients experienced otological complications directly attributable to their leukemia. An additional 28 percent of these patients experienced clinical otological problems for which a leukemic etiology could not be definitely established by histopathological study of their temporal bones. Otological complications occurred most frequently in patients with the acute forms of leukemia, and specifically, in acute lymphocytic leukemia.