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==Pathophysiology== | ==Pathophysiology== | ||
Accumulation of bone deposits because of increased bone remodeling which is bone resorption followed by bone deposition in the otic capsule result in otosclerosis. Audiological findings are directly proportionate to the extent of bone remodeling. | Accumulation of bone deposits because of increased bone remodeling which is bone resorption followed by bone deposition in the otic capsule result in otosclerosis. Audiological findings are directly proportionate to the extent of bone remodeling.<ref name="pmid30975972">{{cite journal| author=Wiatr A, Składzień J, Świeży K, Wiatr M| title=A Biochemical Analysis of the Stapes. | journal=Med Sci Monit | year= 2019 | volume= 25 | issue= | pages= 2679-2686 | pmid=30975972 | doi=10.12659/MSM.913635 | pmc=6475125 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=30975972 }} </ref> | ||
Bone remodeling happens in 3 phases: | Bone remodeling happens in 3 phases: | ||
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The lesions occur mostly in the anterior to the oval window | The lesions occur mostly in the anterior to the oval window by calcifying of annular ligament or by involving stapes footplate (80%). While 30% of cases have the lesion at the round window,21% have it at pericochlear region, and 19% at the anterior segment of the internal auditory canal.<ref name="pmid17245019">{{cite journal| author=Arnold W| title=Some remarks on the histopathology of otosclerosis. | journal=Adv Otorhinolaryngol | year= 2007 | volume= 65 | issue= | pages= 25-30 | pmid=17245019 | doi=10.1159/000098665 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17245019 }} </ref> | ||
==Etiology== | ==Etiology== | ||
Revision as of 03:24, 10 November 2020
Wikidoc
Otosclerosis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] CSN, M.D. Christina Ninan, M.D.
Synonyms and keywords: Otospongiosis
Overview
Otosclerosis is a word derived from the Greek word "sklērós" meaning hardening and oto meaning ear. Otosclerosis is a disorder in which the footplate of the stapes is replaced by an abnormal bone, thereby affecting sound transmission to the inner ear at the level of the oval window.[1] osseous dyscrasia limited to the temporal bone that results in slow, progressive conductive hearing loss(emedicine) (CT) scanning of the temporal bone can often demonstrate foci of demineralization in the otic capsule in cases of cochlear otosclerosis
These changes can occur at many locations in the inner ear. The majority of cases consist of changes in the oval window, but they have also been described in the round window, cochlear apex, posterior to the oval window, posterior and anterior wall of the internal auditory canal (IAC), cochlear aqueduct, semicircular canals, and within the stapes footplate.
Historical perspective
- 1704:Antonio Maria Valsalva identified fixation of stapes as a cause of hearing loss[2]
- 1841:Toyn bee stated, "osseous ankylosis of the stapes to the fenestra ovalis as one of the causes of deafness".[3]
- 1876:Johannes Kessel described stapes surgery as the treatment.[4]
- 1930-1950: Used Julius Lempert’s single-stage fenestration of stapes as treatment.[5]
- 1956:John Shea modernized stapedectomy.[6]
Classification
Embryology
Pathophysiology
Accumulation of bone deposits because of increased bone remodeling which is bone resorption followed by bone deposition in the otic capsule result in otosclerosis. Audiological findings are directly proportionate to the extent of bone remodeling.[7] Bone remodeling happens in 3 phases:
| Phase | Mechanism of action |
|---|---|
| Otospongiosis | Increase in both osteoclast activity and microvascularity |
| Transitional phase | begins with deposits of spongy bone by osteoblasts in areas of previous bone reabsorption |
| Otosclerotic phase | characterized by spongy bone deposits developing into dense bone that narrows the microcirculation previously developed in the otospongiosis phase |
The lesions occur mostly in the anterior to the oval window by calcifying of annular ligament or by involving stapes footplate (80%). While 30% of cases have the lesion at the round window,21% have it at pericochlear region, and 19% at the anterior segment of the internal auditory canal.[8]
Etiology
Differentiating otosclerosis from other diseases
| Conditions mimicking Otosclerosis |
|---|
|
Epidemiology and demographics
- Greater preponderance in women compared to men in a ratio of 2:1.[9]
- Even though the disease begins in the second and third decade of life, it doesn't result in hearing loss until the fourth decade.[10]
- Clinical prevalence of otosclerosis is found to be higher in Caucasians by 0.04%-1% while the histological incidence of otosclerosis increases to 10% in the same.[11].The incidence of histological otosclerosis is 1% and 5% in African and Asian population respectively.[12]
- Autosomal dominant mode of inheritance with incomplete penetrance in certain cases.
Risk Factors
- Genetic factor
- Otosclerosis is an autosomal dominant disease with incomplete penetrance. When 60% of patients were found with family history, 40-50% of patients have it with variable patterns of inheritance. But hearing loss in otosclerosis is found only with family history of the same.[13]
- Hormonal conditions
- Puberty, pregnancy, and menopause increase the occurrence of hearing loss in pre-existing otosclerosis.[14]
- Measles
- Persistent measles virus infection of stapes footplate results in activated osteoclast and inflammatory pathways by TNF-alpha mRNA. The protective function of osteoprotegerin at the otic capsule is inhibited by TNF-alpha and its action on RANK production[15]
Screening
Clinincal associations and Complications
Clinical presentaion
Diagnosis
Treatment
SAMPLE
- USMLE STEP 1
- USMLE STEP 2
- USMLE STEP 2 CK
- USMLE STEP 2 CS
- USMLE STEP 3
- USMLE STEP 3 MCQ
- USMLE STEP 3 CCS92F + atrial fibrillation + numbness/tingling of her right leg; where is the stroke lesion?
- left or right side of the brain?
- à answer = left (contralateral).
- medial or lateral cerebral hemisphere?
- àanswer = medial (homunculus for lower limb is
medial, upper limb and face are lateral).
- anterior or posterior to the central sulcus?
- ànswer = posterior (primary sensory cortexis posterior; primary motor is anterior))
- ↑ Rajput MSA, Arain AA, Rajput AA, Adeel M, Suahil A, Awan MS (2020). "Otosclerosis: Experience With Stapes Surgery". Cureus. 12 (5): e7927. doi:10.7759/cureus.7927. PMC 7265776 Check
|pmc=value (help). PMID 32499972 Check|pmid=value (help). - ↑ Makarem AO, Hoang TA, Lo WW, Linthicum FH, Fayad JN (2010). "Cavitating otosclerosis: clinical, radiologic, and histopathologic correlations". Otol Neurotol. 31 (3): 381–4. doi:10.1097/MAO.0b013e3181d275e8. PMC 2880664. PMID 20195188.
- ↑ Nazarian R, McElveen JT, Eshraghi AA (2018). "History of Otosclerosis and Stapes Surgery". Otolaryngol Clin North Am. 51 (2): 275–290. doi:10.1016/j.otc.2017.11.003. PMID 29502722.
- ↑ Wielgosz R, Mroczkowski E (2008). "[History of endaural surgery]". Otolaryngol Pol. 62 (3): 348–50. doi:10.1016/S0030-6657(08)70269-5. PMID 18652164.
- ↑ Pietruski J (1998). "[Juliusz Lempert (1890-1959): the author of the fenestration technique]". Otolaryngol Pol. 52 (3): 341–6. PMID 9760779.
- ↑ Cheng HCS, Agrawal SK, Parnes LS (2018). "Stapedectomy Versus Stapedotomy". Otolaryngol Clin North Am. 51 (2): 375–392. doi:10.1016/j.otc.2017.11.008. PMID 29397948.
- ↑ Wiatr A, Składzień J, Świeży K, Wiatr M (2019). "A Biochemical Analysis of the Stapes". Med Sci Monit. 25: 2679–2686. doi:10.12659/MSM.913635. PMC 6475125. PMID 30975972.
- ↑ Arnold W (2007). "Some remarks on the histopathology of otosclerosis". Adv Otorhinolaryngol. 65: 25–30. doi:10.1159/000098665. PMID 17245019.
- ↑ Crompton M, Cadge BA, Ziff JL, Mowat AJ, Nash R, Lavy JA; et al. (2019). "The Epidemiology of Otosclerosis in a British Cohort". Otol Neurotol. 40 (1): 22–30. doi:10.1097/MAO.0000000000002047. PMC 6314447. PMID 30540696.
- ↑ Fitzgerald DC (1985). "The aging ear". Am Fam Physician. 31 (2): 225–32. PMID 3883726.
- ↑ Declau F, Spaendonck MV, Timmermans JP, Michaels L, Liang J, Qiu JP; et al. (2007). "Prevalence of histologic otosclerosis: an unbiased temporal bone study in Caucasians". Adv Otorhinolaryngol. 65: 6–16. doi:10.1159/000098663. PMID 17245017.
- ↑ Tato JM, Tato JM (1967). "Otosclerosis and races". Ann Otol Rhinol Laryngol. 76 (5): 1018–25. doi:10.1177/000348946707600512. PMID 6074235.
- ↑ Rudic M, Keogh I, Wagner R, Wilkinson E, Kiros N, Ferrary E; et al. (2015). "The pathophysiology of otosclerosis: Review of current research". Hear Res. 330 (Pt A): 51–6. doi:10.1016/j.heares.2015.07.014. PMID 26276418.
- ↑ Imauchi Y, Lainé P, Sterkers O, Ferrary E, Bozorg Grayeli A (2004). "Effect of 17 beta-estradiol on diastrophic dysplasia sulfate transporter activity in otosclerotic bone cell cultures and SaOS-2 cells". Acta Otolaryngol. 124 (8): 890–5. doi:10.1080/00016480310017081. PMID 15513522.
- ↑ Karosi T, Jókay I, Kónya J, Szabó LZ, Pytel J, Jóri J; et al. (2006). "Detection of osteoprotegerin and TNF-alpha mRNA in ankylotic Stapes footplates in connection with measles virus positivity". Laryngoscope. 116 (8): 1427–33. doi:10.1097/01.mlg.0000225928.35838.e5. PMID 16885748.