Deafness For Medical Finals (based On Newcastle University Learning Outcomes)
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Hospital Based Practice – Deafness. Childhood deafness. • Can be hereditary or acquired.
• •
Hereditary defects may be present at birth, or appear later on. Autosomal dominant syndromes. ○ Wardenburg’s Sensorineural hearing loss Pigment abnormalities Telecanthus.
• ○
○
Klipper – Feil KFS gene on chromosome 8 Congenital fusion of cervical vertebrae Nystagmus Deafness CNS signs. Classically, mirror movements occur. • Voluntary movement in one limb are involuntarily mimicked in another. Treacher – Collins’ Lower lid notching. Oblique palpable fissures. Flattening of malar bones Hypoplastic zygoma. If associated features, known as Franceschetti’s syndrome.
•
○
○
Increased distance between medal canthi.
Mandibular defects
• Ear defects • Deafness. May be due to mutations in TCOF1 gene. Pierre Robin Neonatal difficulty in feeding and breathing. Micrognathia. • Short chin. Cleft palate Eye abnormalities. Prevent tongue falling back by nursing in prone position. Alport’s X – linked or autosomal recesive.
•
X – link form caused by mutations in COL4A5 genes that encode the αS – chain of type _ IV collagen. Sensorineural deafness. Glomerulonephritis with basket weaving of basemenet membranes. • Pyelonephritis • Haematuria • Renal failure. Typical age at death is 20 – 30 years.
•
Autosomal recessive syndromes. ○ Pendred. Sensorineural deafness. Goitre. ○ Usher’s Sensorineural deafness. Retinitis pigmentosa ○ Jewell – Lange – Neilson. Sensorineural deafness. Long QT interval.
•
Acquired. ○ In utero. Maternal infections. • Rubella • CMV • Influenza • Syphilis Ototoxic drugs. Metabolic upset, eg. Maternal diabetes. ○ Perinatal. Anoxia Birth trauma Cerebral palsy Kernicterus ○ Post natal. Meningitis • Main cause Ototoxic drugs Lead Skull fractures.
•
Universal newborn hearing screening ○ Screening within hours of birth is the best way to ensure deafness is detected and managed. Management should be implemented before 6 months of age. ○ The main focus is to avoid language delay. ○ The best test is by detecting otoacoustic emissions (OAE) Microphone in external meatus detects tiny choclear sounds made by movement in the basilar membrane. Abnormal or equivocal in 3 – 8% of neonates. ○ 84% of abnormal results on OEA are due to external ear canal obstruction. In these patients test audiological brainstem responses (ABR). ○
Prevalence. 0.9 – 3.24/1000 have permanent, bilateral heading loss of > 35 dB Increases to 5.95/1000 have when unilateral and moderate hearing loss is included.
•
Subjective hearing loss in the older child. ○ Distraction test. Can be used when patient 6 months or more. Tester in front of patient attracts their attention. Tester to the side tries to distract the patient with a rattle or conversational voice. ○ Conditioned response audiometry. Can be used from 2 years. Child trained to put pegs in a hole or give toys to a parent in response to a particular auditory cue. ○ Speech discriminatation. Can be used from 2 years. Patient touches selected objects, cued by acoustically similar phrases, eg. Key/tree. ○ Pure tone audiogram. Can be used from 5 years.
•
Treatment. ○ Once hearing loss is detected, aim to provide as good hearing as possible to help speaking and education. ○ Teachers of the deaf make arrangements of fitting hearing aids and help monitor progress. Children tend to need higher gain on their hearing aids than adults. Ear moulds may need regular changing to maintain a good fit. ○ Encourage parents of deaf children to talk as much as possible to the child. ○ Children may be educated at Mainstream schools, with visits from teachers or the deaf. I n schools for the deaf or partially hearing. In special units of mainstream schools. ○ Cochlear implants may be suitable. The shorter the duration of deafness, the better the prognosis. Funding decisions should not be delayed. Give pneumococcal vaccine 2 weeks before insertion, or asap if implant already in situ.
Implants may be damaged by. • Direct trauma. • MRI • Surgical diathermy • Dental pulp testers
•
Therapeutic diathermy, used in physiotherapy departments. Ethical issues. • Expensive intervention. ○ Cost per QALY is about £11400 • Debate over what level of deafness should be the cut off for implantation. ○ In the UK, we implant patients with deafness of > 110 dB ○ In the USA, they implant when deafness is > 95 dB •
There is no good research looking at whether patients feel that they benefit from the implant, only whether those around them feel that there is an improvement.
Deafness in Adults. • 10% of UK adults are hearing impaired. • Can be a frustrating and isolating disability. • Management. ○ Determine type of deafness. Conductive.
•
Impaired sound transmission via external canal and middle ear ossicles to foot of stapes. • Has a variety of causes. ○ External canal obstruction. Impacted wax Dicharge from otitis externa Foreign body Developmental abnormalities. ○ Drum perforation. Trauma Barotrauma Infection ○ Problems with ossicular chain. Otosclerosis Infection Trauma ○ Inadequate Eustachian tube ventilation of middle ear with effusion present. Eg. Secondary to nasopharyngeal cancer. Sensorineural. • Results from defects to central area of oval window (sensory) or cochlear nerve (neural). ○ Occasionally due to pathology of more central pathways. • Causes include. ○ Ototoxic drugs. Streptomycin Aminoglycosides.
• ○
○
○ ○
○ •
Especially gentomycin.
Post – infective. Meningitis Measles Mumps ‘Flu Herpes Syphilis Cochlear vascular disease. Meniere’s disease Trauma Presbyacusis.
Rare causes include. ○ Acoustic neuroma ○ B12 deficiency ○ MS
○
○
○
Exclude dangerous causes. Be especially concerned if deafness is unilateral or asymmetric. Acoustic neuroma Cholesteatoma Effusion from nasopharyngeal carcinoma Definitive management may be required. Surgery for perforations or otosclerosis Fitting of suitable hearing aids Fitting of cochlear implants.
•
For profound sensorineural deafness.
• • •
Stimulates residual neural tissue. Takes about 2 hours to fit under GA. An external device processes sound and transits it across the skin to a subcutaneous receiver coil. ○ an electrode in the cochlear via round window. ○ Directly stimulates auditory nerve. The received signal is not normally sound. ○ Rehabilitation is needed to understand the new signals. Benefits include. ○ Improved lip – reading ○ Recognition of environmental sounds. ○ Relieved isolation.
• •
•
Secondary brain CA.
Sudden hearing loss. ○ Sensorineural. Defined as loss of 30 dB in 3 contiguous pure tone frequencies over < 72 hours. Incidence of 5 – 20/100000/year. Partial or complete spontaneous recovery occurs in 30 – 65%. Detailed evaluation reveals underlying disease in 10% • Noise exposure.
•
Gentamicin toxicity.
•
Mumps
•
Acoustic neuroma
• MS • Vasculopathy • TB Investigations. • INR • TSH • Blood glucose • Cholesterol • ESR • FBC • LFT • Viral titres • Audiology
• •
Evoked response audiometry CXR/ MRI
• •
pANCA Lymph node & nasopharyngeal biopsy. ○ Malignancy & TB Management. • Refer promptly to ENT. • Idiopathic causes often respond well to high – dose steroids and hyperbaric oxygen. ○ Have to give promptly.
• •
High dose steroids are no more effective when combined with antivirals
Intratympanic dexamethasone may have salvage role. Prognosis better if. • Early presentation • Mild • Unilateral • No vertigo. Conductive. Cause is almost always identified.. • Infective • Trauma • Occlusive • Fracture.
○
•
Otosclerosis. ○ Prevelence of: 0.5 – 2% clinically 10% subclinically. ○ Cause is mainly Autosomal dominant. Incomplete penetration 50% have a family history 85% are bilateral. ○ Female:Male ratio of 2:1 ○ Pathology. Vascular spongy bone replaces normal lamellare bone of otic capsule.
• Particularly around oval window which fixes the stapes footplate. Symptoms usually appear late in adult life. Made worse by pregnancy, menstruation and the menopause. There is conductive deafness. • Hearing often improved by presence of background noise. Complications. 75% have tinnitus Mild and transient vertigo is common. 10% have Schwartz’s sign. • Pink tinge to tympanic membrane Audiometry with masked bone conduction shows dip at 2 kHz. Cahart’s notch.
○
○
○
•
Treatment. Fluoride. • Contraversial Hearing aids. Surgery.
• •
Stapedectomy.
• • •
Replacing adherent stapes with an implant helps in 90% of cases. Many prefer surgery to wearing a hearing aid. 1 – 4% risk of dead ear.
Stapedotomy.
Presbyacusis. ○ Age related hearing loss from accumulated environmental noise toxicity. ○ Loss of high – frequency sounds starts before 30 years. ○ Rate of loss is progressive thereafter. ○ Deafness due to loss of hair cells is gradual and often not noticed until it is difficult to hear speech. Constanants at 3 – 4 Hz are needed for speech discrimination. ○ Hearing is most affected in presence of background noise. ○ Hearing aids are the usual treatment.
• •
Hereditary defects may be present at birth, or appear later on. Autosomal dominant syndromes. ○ Wardenburg’s Sensorineural hearing loss Pigment abnormalities Telecanthus.
• ○
○
Klipper – Feil KFS gene on chromosome 8 Congenital fusion of cervical vertebrae Nystagmus Deafness CNS signs. Classically, mirror movements occur. • Voluntary movement in one limb are involuntarily mimicked in another. Treacher – Collins’ Lower lid notching. Oblique palpable fissures. Flattening of malar bones Hypoplastic zygoma. If associated features, known as Franceschetti’s syndrome.
•
○
○
Increased distance between medal canthi.
Mandibular defects
• Ear defects • Deafness. May be due to mutations in TCOF1 gene. Pierre Robin Neonatal difficulty in feeding and breathing. Micrognathia. • Short chin. Cleft palate Eye abnormalities. Prevent tongue falling back by nursing in prone position. Alport’s X – linked or autosomal recesive.
•
X – link form caused by mutations in COL4A5 genes that encode the αS – chain of type _ IV collagen. Sensorineural deafness. Glomerulonephritis with basket weaving of basemenet membranes. • Pyelonephritis • Haematuria • Renal failure. Typical age at death is 20 – 30 years.
•
Autosomal recessive syndromes. ○ Pendred. Sensorineural deafness. Goitre. ○ Usher’s Sensorineural deafness. Retinitis pigmentosa ○ Jewell – Lange – Neilson. Sensorineural deafness. Long QT interval.
•
Acquired. ○ In utero. Maternal infections. • Rubella • CMV • Influenza • Syphilis Ototoxic drugs. Metabolic upset, eg. Maternal diabetes. ○ Perinatal. Anoxia Birth trauma Cerebral palsy Kernicterus ○ Post natal. Meningitis • Main cause Ototoxic drugs Lead Skull fractures.
•
Universal newborn hearing screening ○ Screening within hours of birth is the best way to ensure deafness is detected and managed. Management should be implemented before 6 months of age. ○ The main focus is to avoid language delay. ○ The best test is by detecting otoacoustic emissions (OAE) Microphone in external meatus detects tiny choclear sounds made by movement in the basilar membrane. Abnormal or equivocal in 3 – 8% of neonates. ○ 84% of abnormal results on OEA are due to external ear canal obstruction. In these patients test audiological brainstem responses (ABR). ○
Prevalence. 0.9 – 3.24/1000 have permanent, bilateral heading loss of > 35 dB Increases to 5.95/1000 have when unilateral and moderate hearing loss is included.
•
Subjective hearing loss in the older child. ○ Distraction test. Can be used when patient 6 months or more. Tester in front of patient attracts their attention. Tester to the side tries to distract the patient with a rattle or conversational voice. ○ Conditioned response audiometry. Can be used from 2 years. Child trained to put pegs in a hole or give toys to a parent in response to a particular auditory cue. ○ Speech discriminatation. Can be used from 2 years. Patient touches selected objects, cued by acoustically similar phrases, eg. Key/tree. ○ Pure tone audiogram. Can be used from 5 years.
•
Treatment. ○ Once hearing loss is detected, aim to provide as good hearing as possible to help speaking and education. ○ Teachers of the deaf make arrangements of fitting hearing aids and help monitor progress. Children tend to need higher gain on their hearing aids than adults. Ear moulds may need regular changing to maintain a good fit. ○ Encourage parents of deaf children to talk as much as possible to the child. ○ Children may be educated at Mainstream schools, with visits from teachers or the deaf. I n schools for the deaf or partially hearing. In special units of mainstream schools. ○ Cochlear implants may be suitable. The shorter the duration of deafness, the better the prognosis. Funding decisions should not be delayed. Give pneumococcal vaccine 2 weeks before insertion, or asap if implant already in situ.
Implants may be damaged by. • Direct trauma. • MRI • Surgical diathermy • Dental pulp testers
•
Therapeutic diathermy, used in physiotherapy departments. Ethical issues. • Expensive intervention. ○ Cost per QALY is about £11400 • Debate over what level of deafness should be the cut off for implantation. ○ In the UK, we implant patients with deafness of > 110 dB ○ In the USA, they implant when deafness is > 95 dB •
There is no good research looking at whether patients feel that they benefit from the implant, only whether those around them feel that there is an improvement.
Deafness in Adults. • 10% of UK adults are hearing impaired. • Can be a frustrating and isolating disability. • Management. ○ Determine type of deafness. Conductive.
•
Impaired sound transmission via external canal and middle ear ossicles to foot of stapes. • Has a variety of causes. ○ External canal obstruction. Impacted wax Dicharge from otitis externa Foreign body Developmental abnormalities. ○ Drum perforation. Trauma Barotrauma Infection ○ Problems with ossicular chain. Otosclerosis Infection Trauma ○ Inadequate Eustachian tube ventilation of middle ear with effusion present. Eg. Secondary to nasopharyngeal cancer. Sensorineural. • Results from defects to central area of oval window (sensory) or cochlear nerve (neural). ○ Occasionally due to pathology of more central pathways. • Causes include. ○ Ototoxic drugs. Streptomycin Aminoglycosides.
• ○
○
○ ○
○ •
Especially gentomycin.
Post – infective. Meningitis Measles Mumps ‘Flu Herpes Syphilis Cochlear vascular disease. Meniere’s disease Trauma Presbyacusis.
Rare causes include. ○ Acoustic neuroma ○ B12 deficiency ○ MS
○
○
○
Exclude dangerous causes. Be especially concerned if deafness is unilateral or asymmetric. Acoustic neuroma Cholesteatoma Effusion from nasopharyngeal carcinoma Definitive management may be required. Surgery for perforations or otosclerosis Fitting of suitable hearing aids Fitting of cochlear implants.
•
For profound sensorineural deafness.
• • •
Stimulates residual neural tissue. Takes about 2 hours to fit under GA. An external device processes sound and transits it across the skin to a subcutaneous receiver coil. ○ an electrode in the cochlear via round window. ○ Directly stimulates auditory nerve. The received signal is not normally sound. ○ Rehabilitation is needed to understand the new signals. Benefits include. ○ Improved lip – reading ○ Recognition of environmental sounds. ○ Relieved isolation.
• •
•
Secondary brain CA.
Sudden hearing loss. ○ Sensorineural. Defined as loss of 30 dB in 3 contiguous pure tone frequencies over < 72 hours. Incidence of 5 – 20/100000/year. Partial or complete spontaneous recovery occurs in 30 – 65%. Detailed evaluation reveals underlying disease in 10% • Noise exposure.
•
Gentamicin toxicity.
•
Mumps
•
Acoustic neuroma
• MS • Vasculopathy • TB Investigations. • INR • TSH • Blood glucose • Cholesterol • ESR • FBC • LFT • Viral titres • Audiology
• •
Evoked response audiometry CXR/ MRI
• •
pANCA Lymph node & nasopharyngeal biopsy. ○ Malignancy & TB Management. • Refer promptly to ENT. • Idiopathic causes often respond well to high – dose steroids and hyperbaric oxygen. ○ Have to give promptly.
• •
High dose steroids are no more effective when combined with antivirals
Intratympanic dexamethasone may have salvage role. Prognosis better if. • Early presentation • Mild • Unilateral • No vertigo. Conductive. Cause is almost always identified.. • Infective • Trauma • Occlusive • Fracture.
○
•
Otosclerosis. ○ Prevelence of: 0.5 – 2% clinically 10% subclinically. ○ Cause is mainly Autosomal dominant. Incomplete penetration 50% have a family history 85% are bilateral. ○ Female:Male ratio of 2:1 ○ Pathology. Vascular spongy bone replaces normal lamellare bone of otic capsule.
• Particularly around oval window which fixes the stapes footplate. Symptoms usually appear late in adult life. Made worse by pregnancy, menstruation and the menopause. There is conductive deafness. • Hearing often improved by presence of background noise. Complications. 75% have tinnitus Mild and transient vertigo is common. 10% have Schwartz’s sign. • Pink tinge to tympanic membrane Audiometry with masked bone conduction shows dip at 2 kHz. Cahart’s notch.
○
○
○
•
Treatment. Fluoride. • Contraversial Hearing aids. Surgery.
• •
Stapedectomy.
• • •
Replacing adherent stapes with an implant helps in 90% of cases. Many prefer surgery to wearing a hearing aid. 1 – 4% risk of dead ear.
Stapedotomy.
Presbyacusis. ○ Age related hearing loss from accumulated environmental noise toxicity. ○ Loss of high – frequency sounds starts before 30 years. ○ Rate of loss is progressive thereafter. ○ Deafness due to loss of hair cells is gradual and often not noticed until it is difficult to hear speech. Constanants at 3 – 4 Hz are needed for speech discrimination. ○ Hearing is most affected in presence of background noise. ○ Hearing aids are the usual treatment.
