Sudden Sensory Hearing Loss.ppt

1、SUDDEN SENSORY HEARING LOSS,Definition,Severity of the loss. Time course of hearing loss. Frequency spectrum of the loss. Specific audiometric criteria.,Definition,Abrupt or rapidly progressive losses: Awakening with a hearing loss. Hearing loss noted over a few days. Selective low- or high-frequenc

2、y loss. Distortions in speech perception.,Definition,Any noticeable and measurable loss of hearing function. Occurring over a matter of minutes to days. Idiopathic causes.,Epidemiology,5 -20 cases/100,000 persons/year. Female : male = 1:1. Right : left = 1:1. Bilateral: 1-2% of cases. All age groups

3、. Children and elderly persons. The median age: 40 - 54 years.,Differential diagnosis,Idiopathic. Viral infection. Vascular compromise. Intracochlear membrane rupture. Autoimmune inner ear disease.,Differential diagnosis,Category Etiology Infection Bacterial (Postmeningitis, bacterial labyrinthitis,

4、 syphilis) Viral (Mumps, cytomegalovirus) Inflammation Autoimmune (Cogan syndrome,SLE) Multiple sclerosis Trauma Temporal bone fracture Acoustic trauma Perilymph fistula Tumor CPA tumor Temporal bone metastasis Carcinomatosis meningitis Toxins Aminoglycosides Aspirin Vascular Thromboembolism (Macrog

5、lobulinemia, sickle cell disease, post-CABG),Viral infection,17 - 33% of patients recall a recent viral illness. Herpesvirus family (Wilson). Temporal bone histopathologic studies (damage of cochlea - viral injuries): Loss of hair cells and supporting cells Atrophy of the tectorial membrane Atrophy

6、of the stria vascularis Neuronal loss. Mumps-, measles-, and maternal rubella-related hearing loss.,Vascular Compromise,Labyrinthine artery (no collateral vasculature). Cochlea function is exquisitely sensitive to changes in blood supply. Reduction in oxygenation of the cochlea. Thrombosis, embolus,

7、 reduced blood flow, or vasospasm. Changes in systemic BP or intravascular Pco2 alterations in perilymph oxygen tension. Intracochlear hemorrhage fibrosis and ossification of the cochlea.,Intracochlear Membrane Rupture,Membranes: Separate the inner ear from the middle ear. Within the cochlea. Separa

8、te the perilymphatic and endolymphatic spaces. Leak of perilymph fluid into the middle ear (round window or oval window) relative endolymphatic hydrops or intracochlear membrane breaks. Rupture of intracochlear membranes mixing of perilymph and endolymph altering the endocochlear potential.,Autoimmu

9、ne Inner-ear Disease,1979. Cogans syndrome. systemic lupus erythematosus. other autoimmune rheumatologic disorders.,Evaluation,Early improve the prognosis for hearing recovery. Immediate goal: diligent search for a treatable or defined cause. Onset, time course, associated symptoms, and recent activ

10、ities. Reviewing the past medical history. All medications. Thorough head and neck examination. Special attention to the otologic and neurologic examination. Pneumotoscopy (fistula sign) should be included.,Evaluation,Complete audiometric evaluation: pure-tone and speech tests. immittance (tympanome

11、try and acoustic reflex) tests. ABR. OAE. Vestibular tests.,Evaluation,Test Purpose CBC with differential Polycythemia, leukemia, thrombocytosis Sedimentation rate, ESR Nonspecific screen for autoimmune or inflammatory disease, follow with antinuclear antibody and rheumatoid factor if indicated FTA-

12、Abs or MHA-TP Antibody test for Treponema pallidum, Syphilis, congenital or acquired Coagulation studies If indicated, by history Thyroid function tests If indicated, by history Imaging study (See text),Evaluation,Imaging study: Internal auditory canal. Cerebellopontine angle. IAC or CPA tumors: 0.8

13、 - 2%. CPA tumor: MRI with gadolinium DPTA (gold standard test). ABR (screening test).,Evaluation,Younger patients: Vestibular schwannoma . Anatomic abnormality. Noncontrast temporal bone CT scan. Cochlear dysplasia, Mondini malformation, enlarged vestibular aqueduct.,Treatment,Vasodilators. Rheolog

14、ic agents. Antiinflammatory agents. Antiviral agents. Diuretics. Triiodobenzoic acid derivatives. Surgery.,Vasodilators,Improve the blood supply to the cochlea. Reversing hypoxia. Histamine, nicotinic acid, papaverine, procaine, niacin, and carbogen. Carbogen (5% carbon dioxide) inhalation increase

15、perilymph oxygen tension.,Rheologic Agents,Altering blood viscosity improve blood flow and oxygen delivery. Dextrans: hypervolemic hemodilution and affect factor VIII. Pentoxyfylline: greater platelet deformability. Anticoagulants: heparin, warfarin.,Antiinflammatory Agents,Corticosteroids. The mech

16、anism is unknown. Reduction of cochlea and auditory nerve inflammation.,Antiviral Agents,Acyclovir amantadine Famciclovir valaciclovir,Diuretics,Cochlear endolymphatic hydrops. Menieres disease.,Triiodobenzoic Acid Derivatives,Stria vascularis. Maintaining the endocochlear potential. Diatrizoate meg

17、lumine (angiographic contrast agent).,Surgery,Positive fistula test. History of recent trauma or barotrauma. Repair of oval and round window perilymph fistulae.,Results,Spontaneous recovery rates range from 47% to 63%. Mattox and Simmons: Complete recovery :PTA 50 dB improvement. Recovery rate: 63%.

18、,Results,Wilson et al.: Complete recovery: within 10 dB of prehearing loss SRT or PTA. Partial recovery: within 50% of prehearing loss SRT or PTA. Preexisting hearing levels: unaffected ear. 52 patients without treatment: 58% spontaneous recovery rate. Combined with the placebo group in their study, the spontaneous recovery rate was 47%.,Results,Corticosteroid: Published recovery rates range from 41 - 61%. Wilson et al.: