Pediatric Hearing Loss

1. Pediatric Hearing Loss UCLA Head & Neck Surgery Ontario Lau MD

2. Epidemiology congenital SNHL 1-3 per 1000 per live births 10x greater for infants with 1 or more risk factor than those with no risk factors, ie 2% to 5%. late-onset and acquired hearing loss in childhood 6x higher than the incidence of hearing loss in the neonatal period 1% all children have HL

3. Evaluation History: intrauterine infections (most commmon prenatal cause) perinatal infection, maternal drug abuse, low Apgar score (most common perinatal causes) Prematurity, NICU stay, bilirubinemia,family history. Meningitis (most commmon postnatal cause) Physical: microscopic exam; auricle, periauricular pits, craniofacial abnormalities, +/- ocular, thyroid, skin, limb exams look for syndromic cause

4. Evaluation OAE ABR TORCH, meningitis, family hx, craniofacial abnormalities, birth weight <1.5kg, neonatal hyperbilirubinemia, Apgar <4 at 1 minutes, <6 at 5 minutes, prolonged NICU stay or ECMO or mechanical vent, exposure to ototoxic meds. Behavior observation audiometry (birth to 6 mos) Visual Reinforcement Audiometry (6mos-3yrs) Conventional play audiometry (3-6 yrs) Standard Audiometry (6 yrs+)

5. Ancillary Tests Imaging: CT temporal bone: inner ear disorders, cholesteatoma, & osteodysplasias. CBC, lipid profile, IgM assay for TORCH (Toxoplasmosis, Other[syphilis], Rubella, Cytomegalovirus, Herpes simplex) Connexin-26 test Other tests as indicated by ddx.

6. Causes of HL 5-10% prenatal causes (TORCH, teratogens) 5-15% perinatal causes (hypoxemia etc) 10-20% postnatal causes (meningitis etc) 20-30% UNKNOWN 30-50% genetic

7. Acquired prenatal hearing lossCongenital Cytomegalovirus • most common infectious cause, >4000 annual cases • Incidence of infection: 1-2 cases/100 live birth • <5% develop multiorgan dx 50% of those develop HL • 5-15% silently infected infants eventually develop HL • Oto SSx: B progressive high freq SNHL • Other SSx: Cerebral calcification, microcephaly, mental retardation, hepatosplenomegaly, jaundice.

8. Acquired prenatal hearing lossCongenital Cytomegalovirus Dx: serum anti-CMV IgM, CMV DNA from body fluid,+ intranuclear inclusions (owl eyes) in renal tubular cells in urinary sediment (1 to 2 weeks of life) Rx: Ganciclovir—little effect for HL since damage happened already in utero

9. Acquired prenatal hearing lossCongenital Syphilis Pathophysio: transplacental transmission, 100% inoculation rate 40% perinatal death Oto SSx: frequent +Hennebert sign (aka +fistula sign) Early deafness birth to 3 yo delayed 8-20 yo. Other SSx: Hutchinson triad: abnormal central incisors (aka Hutchinson teeth), interstitial keratitis of the eye, bony abnormalities Dx: RPR,VDRL(sensitive); FTA-ABS(specific) Tx: PCN

10. Acquired prenatal hearing lossCongenital Rubella Rare since vaccination (0-3 per year now in USA) Pathophysio: vasculitis resulting in tissue necrosis Oto SSx: B often asymmetric severe to profound SNHL Other SSx: growth delay, learning disability, congenital heart disease, and ocular, endocrinologic, and neurologic abnormalities. Dx: urine/throat/amniotic fluid clx, antirubella IgM

11. Inner Ear Dysmorphologies • Time frame: membranous labyrinth is interrupted during 1st trimester  • Etiologies: Genetic or teratogenic exposure • Classifications • membranous labyrinth ONLY (seen at autopsy) • Osseous & membranous labyrinth ( seen in CT)

12. Inner Ear Dysmorphologies • Incidence: 20% congenital SNHL will show abnormal inner ear on CT temporal bone • Bony: Dilated Vestibular aqueduct >cochlea>SCC (as reflected by modern imaging technology)

13. Inner Ear Dysmorphologies membranous labyrinth ONLY • Complete membranous labyrinthine dysplasia (Siebenmann-Bing) • Limited membranous labyrinthine dysplasia • Scheibe dysplasia (cochleosaccular dysplasia) MOST common membranous labyrinthine dysplasia • Cochlear basal turn dysplasia

14. Bing-Siebenmann Extremely rare Associated with Jervell and Lange-Nielsen syndrome and Usher syndrome.

15. Scheibe dysplasiacochleosaccular dysplasia • Pathophysio: incomplete development of the pars inferior • Cochlea dysplasia: severa in the basal turn, lessen toward apex, or severe throughout • Saccule: collapsed • Organ of Corti: partial or completely missing • SCCs & utricle: NORMAL • OtoSSx: SNHL • Associated w/ Usher syndrome & Waardenburg syndrome

16. . Cochleosaccular Dysplasia: A Morphometric and Histopathologic Study in a Series of Temporal Bones. Sampaio, Andre; Cureoglu, Sebahattin; Schachern, Patricia; Kusunoki, Takeshi; Paparella, Michael; Oliveira, Carlos Otology & Neurotology. 25(4):530-535, July 2004. FIG. 1. (A) In the apical turn of this right temporal bone from case 10, there is a large cystic area (arrow) in the stria that intersects in its apical portion with a hydropic Reissner's membrane (arrowhead). O, organ of Corti represented by supporting cells; T, deformed tectorial membrane; S, atrophic stria vascularis. (B) There are strial cysts (arrow) in the lower basal turn of this left temporal bone from case 2. (C) In the lower basal turn of this right temporal bone from case 8, there is a strial concretion (short arrow), a collapsed Reissner's membrane (arrowhead), and an amorphous substance (long arrow) within a rolled tectorial membrane. 2

17. Inner Ear Dysmorphologies osseous & membranous labyrinth • Complete labyrinthine aplasia (Michel) 1% • Cochlear anomalies • Cochlear aplasia 3% • cochlear hypoplasia 15% • Incomplete partition (Mondini) 55% • Common cavity 26%* *Jackler RK, Luxford WM, House WF: Congenital malformations of the inner ear: a classification based on embryogenesis, Laryngoscope Suppl 97:2, 1987

18. Michel: complete labyrinthine Aplasia Exceedingly rare. Associated w/ anencephaly & thalidomide exposure. Overestimated due to confusion with acquired labyrinthine ossification.

19. Mondini: incomplete partition • Pathphysio: arrest at 7th week gestation 1.5 turn cochlea • Oto SSx: normal to profound SNHL • Other SSx: • 20% SCC deformities; • dilated cochlear aquaduct: perilymphatic gushers & meningitis

20. Mondini: incomplete partition • CT/MRI findings: • smaller cochlea (5-6mm vs 8-10mm vertical dimension of normal cochlea) • absence of a scalar septum

21. Common Cavity • Pathphysio: arrest at 4th week otocyst stage or later • CT/MRI findings: • Empty ovoid space (average 7mm vertically, 10mm horizontally) • Common cavity cochlear ANTERIOR to the IAC on axial CT • Oto SSx: variable SNHL, usually poor

22. Common Cavity Implanting Common Cavity Malformations Using Intraoperative Fluoroscopy. Coelho, Daniel; Waltzman, Susan; Roland, J Otology & Neurotology. 29(7):914-919, October 2008. DOI: 10.1097/MAO.0b013e3181845827 FIG. 2 . A transorbital plain x-ray intraoperative view. Note that the array has passed into the IAC. The arrow denotes the junction between the common cavity and the IAC as seen in this orientation. Inset outlines the lumen of the common cavity (cc) and the IAC. Reprinted with permission from Fishman AJ, Roland JT Jr, Alexiades G, Mierzwinski J, Cohen NL. Fluoroscopically assisted cochlear implantation. Otol Neurotol 2003;24:882-6. 2

23. Inner Ear Dysmorphologies osseous & membranous labyrinth • Labyrinthine anomalies • Semicircular canal dysplasia •  Semicircular canal aplasia • Aqueductal anomalies • Enlargement of the vestibular aqueduct • Enlargement of the cochlear aqueduct • Internal auditory canal anomalies • Narrow IAC • Wide IAC *Jackler RK, Luxford WM, House WF: Congenital malformations of the inner ear: a classification based on embryogenesis, Laryngoscope Suppl 97:2, 1987

24. Semicircular Canal Dysplasia • 40% malformed cochlea a/w dysplasia of lateral SCC • Lateral>>post/superior • Pathphysio: arrest at 6th week • CT/MRI findings : short, broad cystic space confluent with the vestibule

25. Enlargement of the Vestibular Aqueduct • Epid: most common radiographically detectable malformation of the inner ear • Pathphysio: Acquired abnormal communication between the subarachnoid space and the fluid chambers of the inner ear • Oto SSx: • born w/ normal or mildly impaired hearing that gradually worsens; • hearing variable, 40% profound SNHL • CHL possible: AVOID STAPEDECTOMY! (a/w perilymphatic gusher)

26. Enlargement of the Vestibular Aqueduct • CT/MRI findings : • CT: VA> 2mm (normal 0.4-1mm) • a/w cochlea or SCC malformation • MRI: Dilated endolymphatic sac, sometimes >2cm • Usually bilateral • RX: CI, avoid endolymphatic surgery/stapedectomy

27. Wide Internal Auditory Canal Usually incidental finding in normal hearing subjects CT/MRI findings : IAC>10mm a/w spontaenous CSF otorrhea & gusher during stapes surgery obtain CT for congenital CHL!

28. Narrow Internal Auditory Canal Pathphysio : agenesis of CN VIII CT/MRI findings : IAC<3 mm, bony canal only transmits CN VII Relative contraindication to CI

29. GENETIC HL • >50% non-syndromic • 75% to 80% autosomal recessive • 15% to 20% autosomal dominant • 1% to 2% is X-linked. • <<1% mitochondrial inheritance

30. Autosomal Recessive DisordersUsher syndrome • Most common cause of congenital deafness • 50% deaf-blind in USA • Pathophy: unknown, could also be autosomal dominant, X-linked • SSx:Variable SNHL, progressive retinitis pigmentosa • Dx: Electroretinography

31. Usher syndromesubtypes I: profound congenital SNHL, No vestibular response Blind by childhood, most common II: moderate to severe SNHL, normal vestibular response, blind by early adulthood III: progressive SNHL, progressive vestibular dysfunction, varied progression in blindness

32. Autosomal Recessive DisordersPendred syndrome • Pathophy: Defect in tyrosine iodination from pendrin (chloride/iodide transporter) • OtoSSx: severe to profound SNHL, a/w Mondini deformity, dilated vestibular aqueducts. • Other SSx: multinodular goiter in 8-14 yo • Dx: + perchlorate test • Rx: Thyroid supplement

33. Autosomal Recessive DisordersJervell and Lange-Nielsen Syndrome • Pathophy: mutation in potassium channel • OtoSSx: B severe to profound SNHL • Other SSx: cardiac abnormalities, recurrent syncope, sudden death • Dx: EKG ( prolonged QT, large T-wave) • Rx: beta-blocker, HA

34. Autosomal Recessive DisordersGoldenhar Syndrome • aka Hemifacial Microsomia/ Oculoauriculovertebral spectrum • Pathophy: uncertain, malformation of 1st and 2nd arch derivatives • OtoSSx: • microtia/EAC atresia, ossicular malformationCHL • abnormal CN VII, SCC, oval windowSNHL

35. Autosomal Recessive DisordersGoldenhar Syndrome • Other SSx: • Ocular: epibulbar dermoids, colobomas of upper eyelids • Vertebral: fusion or absence of cervical vertebrae • Facial asymmetry • Mild mental retardation • Dx: PE

36. Autosomal Dominant DisordersWaardenberg Syndrome • Pathophy: abnormal tyrosine metabolism • OtoSSx: U/B SNHL, +/- vestibular dysfunction • Other SSx: • Pigmentary abnormalities (heterchromic iriditis, white forelock, patch skin depigmentation • Dystopia canthorum • Synophrys • Flat nasal root, • Hypoplastic alae

37. Autosomal Dominant DisordersWaardenberg Syndrome • Subtypes • I: + telecanthus, 36-66.7% SNHL • II: -telecanthus, 57-85% SNHL • III: type 1 + hypoplasia or contracture of the upper limbs. (=Klein-Waardenburg syndrome) • IV: WS + Hirschsprung disease (Waardenburg-Shah syndrome) autosomal recessive • Dx: clinical H&P, family Hx

38. Autosomal Dominant DisordersStickler Syndrome • =Progressive Arthro-Ophthalmpathy • Pathophy: mutation in type II and type XI collagen, variable phenotype; 1:10,000 • OtoSSx: progressive SNHL, MHL ( from ETD of clefting) • Other SSx: • myopia, retinal detachment • Marfanoid habitus • joint hypermobilities • Midline clefting • Dx: clinical H&P, family Hx

39. Autosomal Dominant Disorders Branchio-Oto-Renal Syndrome • =Melnick Fraser Syndrome, 1 in 40,000 newborns • Pathophy: branchial arches, otic & renal abnormal development • OtoSSx: • preauricular ear pits/tags, microtia, EAC stenosis; middle/inner ear anomalites • 50% MHL, 30% CHL, 20% SNHL • Other SSx: varied renal abnormalities (agenesis to mild dysplasia) • Dx: Renal US or pyelography; renal abnormalities frequently asymptomatic

40. Autosomal Dominant DisordersTreacher Collins Syndrome • =Mandibulofacial dysostosis • Pathophy: uncertain. • OtoSSx: microtia/EAC atresia, preauricular fistulas, malformed ossicle CHL, widened aqueduct, aberrant CN VII • Other SSx: mandibular hypoplasia-fishmouth; downward slanting palpebral fissures, coloboma of lower eyelids, palate defects. Choanal atresia • Dx: clinical H&P, family Hx • Rx: BAHA, possible atresia repair

41. Autosomal Dominant DisordersNeurofibromatosis I • =Von Recklinghausen disease • Pathophy: NF 1 in chromosome 17 • OtoSSx: retrocochlear HL • NF 1 (2/7 characters) • >6 café-au-lait spots • 2 or more neurofibromas or 1 plexiform neurofibroma • Axillary or groin freckling • Optic nerve glioma • Lisch nodules (eye hamartomas) • Bony lesions • +family Hx • 5% risk of U vestibular schwannoma

42. Autosomal Dominant DisordersNeurofibromatosis 2 • Pathophy: mutation in Merlin ( tumor suppressor gene) in chromosome 22 • OtoSSx: retrocochlear HL • NF 2 • B vestibular schwannoma by 2nd decade of life • Family h/o NFII in a 1st degree relative PLUS • A) unilateral vestibular schwannoma at <30 yo • B) 2 neurofibroma + other intracranial & spinal cord tumors (gliomas/schwannomas/meningiomas)

43. Autosomal Dominant DisordersApert Syndrome • =Acrocephalosyndactyly • Pathophy: autosomal dominant or sporadic • OtoSSx: Stapes fixation CHL, patent cochlear aqueduct, large subarcuate fossa • Other SSx: • lobster claw hands • midface abnormalites (hypertelorism, proptosis, saddle nose, high-arched palate) • craniofacial dysostosis • trapezoid mouth

44. Autosomal Dominant DisordersCrouzon Syndrome • = Craniofacial dysostosis , Pathophy: unknown • OtoSSx: microtia/EAC atresia, malformed ossicle CHL, • Other SSx: midface abnormalites (hypertelorism, small maxilla, exophthalmos, parrot nose, short upper lip, craniofacial dysostosis, mandibular prognathism

45. Sex-linked DisordersAlport Disease • Pathophy: 80% X-linked or autosomal dominant/recessive. Abnormal Type IV collagen formation in glomerular basement renal failure • OtoSSx: B degeneration of organ of Corti and stria slowly progressive SNHL • Other SSx: hematuria, progressive nephritis, macular/corneal lesions • Dx: skin or renal bx w/ electron microscopy, UA • Rx: HD, renal transplant.