Otosclerosis

Otosclerosis

1. OTOSCLEROSIS Moderator-Dr.Mohan Presenter-Dr.Razal

2. Definition A primary disease of the bony otic capsule characterized by abnormal removal of mature bone by osteoclasts and replacement with woven bone of greater thickness, cellularity and vascularity. Clinical Otosclerosis refers to a lesion that involves the stapes bone or stapidovestibular joint. 2

3. Most common site is fissula ante fenestram (anterior to the stapes foot plate) and also seen in the fossula post fenestram (area in front and behind oval window) The bone of otic capsule is unique that it exhibits very low remodeling and contains small regions of immature cartilaginous tissue called GLOBULI INTEROSSEI. Blue Mantles, an earliest histological alterations of otic capsule that stain more basophilic.

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5. Epidemiology Race % incidence of Caucasian 10% Asian 5 % African American 1% Native American 0%

6. Epidemiology Gender Histologic otosclerosis – 1:1 ratio Clinical otosclerosis – 2:1 (W:M) Increase progression during pregnancy (10%-17%) Bilaterality more common (89% vs. 65%)

7. Epidemiology Age 15-45 most common age range of presentation Youngest presentation7 years Oldest presentation 50s 0.6% of individuals <5 years old have foci of otosclerosis

8. Etiology The exact cause is unknown but many factors have been proposed such as: Genetic Autoimmune Infections Endocrine (pregnancy ) Trauma Vascular 8

9. Hereditary (Autosomal Dominant) More common in whites than blacks Uncommon in Asian Sporadic cases were reported. Defects in COL1A1 Gene defects in expression of the C OLlAl gene has revealed a significant association between both familial and sporadic cases Genetic

10. Type 1 osteogenesis imperfecta shares both clinical and histologic similarities with otosclerosis. Half of all patients with type 1 osteogenesis imperfecta develop hearing loss that is clinically indistinguishable from clinical otosclerosis. Patients with clinical otosclerosis have blue sclera , a feature that is found in all patients with type 1 osteogenesis imperfecta . Osteogenesis Imperfecta

11. Infectious (Measles) Measles RNA was found in footplate specimens Elevated levels of anti measles antibody found in perilymph from patent undergoing stapedectomy. 11

12. a form of autoimmune disease with humoral autoimmunity to Type II collagen. Elevated circulating antibodies to type II collagen are found in patients of otosclerosis 12 Autoimmune

13. Pathogenesis 13

14. Affects the Otic and labyrinth Capsule Enlargement of the Perivascular Space Bone Absorption by osteoclast activity New Bone deposition by osteocytes Containing vascular space in center Lamellar Bone With time mucoperiostium of middle ear increases in thickness and becomes vascular Reddish Hue through the TM and disease advances Involvement of Bony labyrinth Involvement of foot plate. Cochlear Otosclerosis Stapedial Otosclerosis

15. Histologically Lesion can be divided into Active-Spongy structure immature osseous tissue with numerous dilated vascular channels with osteoclastic giant cells Inactive/ Mature End stage of bone transformation ,characterized by solid compact lamellar tissue . Siebenmann – first to describe the microscopic appearance

16. 16 The foci demonstrates two phases: Early spongiotic phase ( otospongiosis ) Osteocytes, histiocytes , osteoclasts Active reabsorption of bone Stains blue (blue mantles) on using H&E stain Dilated vessels ( Schwartze’s sign ) Late or Sclerotic phase Formation of new bone in resorption areas New bone is dense and sclerotic Stains red on using H&E stain Starts in endochondral bone then involves endosteal & periosteal layers and membranous labyrinth as disease progress

17. Anterior Focus Most common, at fissula ante fenestram Posterior Focus Lesion spreading from posterior oval window to annular ligament Circumferential Lesion flows across the ligament totally obliterating the annular ligament Biscuit type Lesion replacing entire footplate, but no involvement of annular ligament leading to a solid footplate 17 Types of Stapedial fixation

18. Obliterative Completely obliterates the oval window Other areas are: Round window, the apex of the cochlea, the cochlear aqueduct, the semicircular canals, and the stapes footplate itself 18 Types of Stapedial fixation

19. Diagnosis 19

20. Gradual onset of hearing loss progressing slowly In 70% cases hearing loss is bilateral Usually becomes apparent around the age of 30 Loss noticeable when it reaches 25 to 30 dB Unilateral loss noticed even later, problem with localization of sound Positive family history 20 History

21. SYMPTOMS Low modulated voice (BC is more ,patients hears their own voice. Deafness-Mainly Conductive hearing loss, Paracussis Willisi-Patient will hear better in noisy surroundings. Tinnitus Vertigo Clinical Features

22. Hearing Loss Conducting Hearing Loss (CHL) Stapedial fixation Hearing impairment ranging from 5dB to 60dB . Caused primarily by narrowing and impairment of the annular ligament, at the posterior stapediovestibular joint space. Sensorineural Hearing Loss (SNHL) Cochlear otosclerosis the sensory and neural elements of the cochlea, such as hair cells, spiral ganglion cells and stria vascularis , are intact or their impairment is insufficient to account for the observed sensorineural hearing impairment. 22

23. OTOSCOPY SCHWARTZE SIGN :- red blush color occasionally seen over promontory or anterior to oval window Pneumo-otoscopy used to rule out other causes of CHL such as middle ear serous fluid or small perforation TUNING FORK TEST Hearing loss progresses form low frequencies to high frequencies Rinne Test-Negative Weber Test - Laterlized to worst ear. ABC-Normal 23 Physical Examination

24. Pure Tone Audiometry CARHART’S NOTCH Proposed theory Stapes fixation disrupts the normal ossicular resonance (2000 Hz) Normal compressional mode of bone conduction is disturbed because of relative perilymph immobility Mechanical artifact Reverses with stapes mobilization Speech Audiometry Normal except in those with cochlear involvement.

25. Tympanometry : As type curve 26 Impedance

26. High resolution CT scan Shows subtle areas of demineralization In case of cochlear involvement it shows “double ring sign” MRI Done for patients with unusual presentation Detects congenital anomalies of cochlea Excludes retrocochlear pathology eg . Acoustic neuroma 27 Radiological Investigations

27. Differential Diagnosis Ossicular discontinuity Congenital stapes fixation Malleus head fixation Paget’s disease Osteogenesis imperfecta

28. TREATMENT 29

29. Treatment Options Hearing aid Medical management Surgical management- The ‘Gold’ reference standard of Diagnosis is Surgery 30

30. Hearing Aid Very effective in early stage of disease But can be used in advance stage, if: Surgery is contraindicated Patient refuses the surgery In far-advance cases it is required, even after stapedotomy 31

31. Medical Management Aim is to Stabilize the disease by reduction of the osteoclastic bone resorption increase osteoblastic bone formation Inhibits proteolytic enzymes that are cytotoxic to cochlea. Slows the progression of sensorineural hearing loss Not commonly used 32

32. Tab . Sodium fluoride Dose : 50 – 75 mg/ day OD Duration : 3 months – 2 years Function helps to hasten the maturity of active focus and arrest further progression of cochlear loss It has antienzymatic action on proteolytic enzymes which are cytotoxic to cochlea. Indications: Cochlear otosclerosis Active stapedial otosclerosis 33 Sodium Fluoride T herapy

33. Side effects : Fracture of long bones and spine due to fluorosis. Nephritis. Gastritis Contraindications: Pregnancy & lactation Patient with kidney stones / nephritis Patient with RA Sodium Fluoride Therapy

34. Surgical Management Poorer ear always chosen for surgery Done preferably under local anesthesia so patient can notify surgeon if vertigo occurs during procedure Options are: Stapedotomy Stapedectomy Lasers -Lesser complications 35

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