Inner Ear Diseases PDF

Diseases of the inner ear Dr. Shorash Sindi FIBMS (ENT) University of Duhok college of medicine  HEAD AND NECK Internal ear Lateral semicircular canal Ampulla Anterior semicircular canal...

Diseases of the inner ear Dr. Shorash Sindi FIBMS (ENT) University of Duhok college of medicine  HEAD AND NECK Internal ear Lateral semicircular canal Ampulla Anterior semicircular canal Vestibular aqueduct Posterior semicircular canal Dura mater Vestibular nerve Cochlear nerve Internal acoustic meatus Utricle Facial nerve [VII] Facial nerve [VII] Intermediate nerve (sensory root of VII) Stapes in Vestibulocochlear oval window nerve [VIII] Helicotrema Vestibule Cochlea Utriculosaccular I duct Tympanic membrane Round window Saccule Scala vestibuli 0 Structures of the internal ear (right) Scala vestibuli Vestibular membrane Cochlear duct Tectorial membrane Scala tympani Cochlear duct Lamina of modiolus Nerve fibers Spiral ligament Modiolus Spiral organ Spiral ganglion Outer hair cells Pillar cells I Cochlear nerve Basilar membrane Scala tympani Inner hair cells Cross section through cochlea 526 Introduction Anatomy: The inner ear consist of : 1-the cochlea : concerned with hearing 2-the vestibular apparatus responsible for equilibrium : A. three semicircular canals: B. Utricle: C. Sacule:  Symptoms of inner ear diseases: Deafness ( sensorineural hearing loss ‘SNHL’ ) Vertigo : an illusion of movement of the body or the environment. Tinnitus : abnormal noises in the ear in the absence of auditory stimuli.  I'm B –Peripheral causes of vertigo: 4 Labyrinth 1-Benign paroxysmal positional vertigo (BPPV): 2-Meniere’s disease (Endolymphatic hydropis) 3-Vestibular neuritis 4- Labyrinthitis: 2 Benign Paraxysmal Positional vertigo This is a condition characterized by episodic Vertigo that occurs with the head is moved in certain positions Ifrfadmoveenths AbhoventacentII. o subservent moveotoliths that through serif  Pathophysiology of BPPV canalolithiasis theory the otoliths (calcium carbonate particles) which cover the sensori- neuroepithelium of the utricle These particles detached from hair 0 cells in the utricle and inappropriately enter the posterior semicircular canal since this is the most dependent of the three canals, during movement of the head these particles stimulate the hair cells of the semicircular canal results in vertigo. To BPPV The most common type Clinical features The attack of vertigo lasts only for seconds The attack triggered by certain head movement like turning in bed or looking up at an object. no hearing loss, no tinnitus, no abnormal neurological symptoms. BPPV The diagnosis is clinical The diagnostic bed side test is DIX Hallpike maneuver  Dix-Hallpike maneuver 1.Patient in sitting position 2.The head is turned 45 degree to the left or right, then the patient rapidly laid backward with the head over the edge of the bed 30 degree below the horizontal 3.The patient asked if there is vertigo and observed for the nystagmus, if occurred → positive test. 4- If neither occur after 30 seconds the patient returned back for sitting position, the test is repeated with the head turned to the opposite side  0 K O https://youtu.be/D6qEdlFVxig BPPV Horizontal Abnormal jerky movement of the eye The characters of nystagmus in BPPV 1- torsional with vertical component 2- it has a latent period before starting 3- transient nystagmus 4- fatiguable (slowly settles) Treatment of BPPV 1- reassurance that the disorder invariably settles spontaneously 2- repositioning (Epley’s) manoeuvre a complex series of head movement that may be performed in the clinic attempting to tip the displaced otoliths out of the semicircular canal. j Labyrinthine exercises to speed up vestibular compensation Rarely surgery on the posterior semicircular canal is needed i 2 Meniere’s disease ts Is an inner ear disease characterized by Episodic vertigo, hearing loss, tinnitus and ear fullness  Pathogenesis Distension of the membranous labyrinth from fluid accumulation (endolympatic hydropis) I is postulated as a cause of this condition am Meniere’s disease yn10d The attack occurs due to small ruptures in Reissner I membrane leading to mixing of the endolymph and perilymph. 0 o O p Meniere’s disease SENT Clinical features 0 The duration of the vertigo last usually for 30min - 4h The vertigo is often disabling and very acute in onset Associated with nausea and vomiting The patient feels tired for the next few days after the attack. of aura PEE Meniere’s disease 2.hearing loss is sensorineural in type and in early stage of the disease affects the lower frequencies and return to normal after the attack (fluctuating hearing loss ) 3.Tinnitus and a feeling of fullness or pressure in the affected ear may precedes the attack  over TIMES Over the course of the disease hearing loss and tinnitus become permanent The disease is usually unilateral initially but can become bilateral Diagnosis cochleography Audiooram low frequency SNHL Meniere’s disease Treatment In acute phase treatment consists of vestibular sedative (e.g cinnarizine) pyride In long term: betahistine, diuretics, avoidance of caffeine and salt and reassurance can reduce the number of the attacks and increase the patient ability to cope with the attacks dont caffeine betm Meniere’s disease Medical ablation therapy Ototoxic Gentamicin is given through the tympanic membrane will be absorbed through the round window and selectively damage the vestibular cells relative to the cochlear cells. attentive Meniere’s disease Surgical treatment A. Endolymphatic sac surgery: by transmastoid approach. the endolymphatic sac either decompressed or a shunt is placed in the sac that communicates with the subarachnoid space or mastoid cavity. B-Vestibular nerve section— a vestibular nerve section provides a definitive treatment of unilateral Meniere’s disease in patients with serviceable hearing Vestibular neuritis Vestibular neuritis I Is a viral infection of the vestibular nerve x̅ Vestibular neuritis HX of viral Infection Aetiology Most likely due to viral infection supported by polymerase chain reaction (PCR) to detect viral DNA In postmortem study Herpes simplex virus type one (HSV-1) 1140 Vestibular neuritis it Clinical presentations Acute spontaneous vertigo associated with nausea and vomiting a Aggravated by head movement and minimized by keeping the head still and eyes shut. During walking the patient tends to fall to the side of the affected labyrinth  Vestibular neuritis The symptoms subside over the following days But many patients have residual imbalance that last for months. Hearing is normal (no deafness, tinnitus) affected labyrinth is not Vestibular neuritis Acute attack there is nystagmus (horizontal Towardsunaffectedd towards the unaffected side) The patient characteristically rotate towards 2 the affected side when attempt to march on the spot with their eyes closed (positive Unterberger test) v wmÑ Vestibular neuritis The Unterberger stepping test is a simple means of identifying which labyrinth may be dysfunctional in a peripheral vertigo. Procedure: ask the patient to undertake stationary stepping for one minuteE with their eyes closed. A positive test is indicated by rotational movement (>30°) of the patient towards the side of the lesion. Vestibular neuritis Absent neurological signs Diagnosis is clinical i Vestibular neuritis Treatment : Corticosteroids with antiviral drugs During acute attack vestibular sedative drugs and rest plochloroperazine Admit flick Traumatic inner ear disease (Temporal bone fractures) 20 % of skull base fractures Aetiology: 1. RTA 2. Blunt trauma to the lateral surface of the skull Classification: 1. longitudinal fractures 80 -90 % 2. transverse fractures 10- 20% if 1- Longitudinal fractures 1- Longitudinal fractures 2- Transverse fractures 2- Transverse fractures  Longitudinal fracture Usually spare the labyrinth The fracture involves the external meatus and the roof of the of the middle ear. Deafness, which type?  Longitudinal fracture Conductive deafness due to ossicular dislocation Bleeding into the middle ear cleft (haemotympanum ) Tympanic membrane rupture Longitudinal fracture Facial palsy is uncommon Bleeding from the ear and CSF otorrhea can result if the tympanic membrane is disrupted. Battle’s sign: ecchymosis in the post-auricular area. Transverse fracture Transverse fracture usually involve the labyrinth and thus lead to sensorineural hearing loss with profound vertigo. This vertigo will settle with time as central compensation occurs. Facial palsy occurs in 50% of cases. Treatment 1. Haemotympanum: conservative treatment, usually resolves within 3-4 week 2. Tympanic membrane perforation: usually heals within 3 months, if persists then myringoplasty Treatment 3. Facial nerve paralysis: a-Immediate paralysis treated by surgical exploration with attempt to repair the nerve. b- Delayed paralysis: usually treated conservatively 4- CSF leak: a- medical treatment: bed rest, head elevation, stool softener, lumbar drain and antibiotics to prevent meningitis b- surgical closure of the defect if it persist for more than 10 days.  Acoustic trauma: Acute acoustic trauma may arise from sudden very loud sound as in explosion The effects: Sensorineural hearing loss (SNHL, most common) Conductive hearing loss due to tympanic membrane rupture or damage to the middle ear. Noise-Induced Hearing Loss Noise-induced hearing loss (NIHL) is a major cause of preventable SNHL. SNHL may follow chronic exposure of noisy occupations, which are less intense sounds than the acoustic trauma. 1. Temporary threshold shift: the hearing loss recovers after an interval of time ranging from few minutes to few hours up to 2 weeks. 2. Permanent threshold shift: the hearing loss becomes permanent and does not revert back. Factors Affecting Noise Trauma The SNHL caused by noise trauma depends on the following factors, which should be kept in mind for the safety of hearing: 1. Frequency: the noise of 2,000–3,000 Hz frequencies causes more SNHL than lower and higher than these frequencies. 2. Intensity and duration: as the intensity of noise increases, the permissible 8 time for exposure is reduced (i.e do not listen to loud noice for too long) 3. Continuous interrupted: the continuous noise is more harmful than the interrupted one. 4. Susceptibility: some persons are genetically susceptible to noise trauma. 5. Pre-existing ear disease: can affect the impact of noise on the inner ear. Pathology Noise-induced hearing loss damages hair cells, which begin at the basal turn of cochlea. Outer hair cells are affected earlier than the inner hair cells. Clinical Features Shouting to talk at workplace. Aural fullness, tinnitus, or muffled hearing after the work.  Pure Tone Audiogram (PTA) The PTA shows following characteristic findings in NIHL: 1. Early stage: A typical notch at 4000 Hz is seen in both for air and bone conduction. It is usually symmetrical in both the ears. Patient complains of high-pitched tinnitus and difficulty in hearing only in noisy surroundings. 2. Late stage: The notch deepens and widens to involve lower and higher frequencies. Involvement of speech frequencies (500, 1,000 and 2,000 Hz) result in hearing difficulty even in calm surroundings also. Prophylaxis Persons who work in factories where noise is above 85 dB should have following precautions: ❖Pre-employment and then annual audiograms for early detection. ❖Use of ear protectors (ear plugs or earmuffs) provides protection up to 35 dB. ❖Rehabilitation is required in cases of NIHL. Sudden sensorineural Hearing Loss Sudden sensorineural hearing loss (SSNHL) develops over a period of hours, or a few days and hearing loss may be partial or complete. Though mostly unilateral, it may affect both the ears. Patient may have associated symptoms of tinnitus and temporary spell of vertigo.  Etiology 1. In most of the cases, it is idiopathic as the cause remains obscure in 85–90% of the cases. 2. Three etiological factors speculated are viral, vascular and the rupture of cochlear membranes. 3. Spontaneous formation of perilymph fistulae in the oval or round window can occur. 4. The causes of sudden hearing loss, which must be ruled out in idiopathic SSNHL, are listed in next slide. 5. Upper respiratory infections (URI) within 1 month of hearing loss. The cause of sudden hearing loss should be discovered by detailed history and physical examination including audiometry. Investigations 1. Laboratory: The following laboratory investigations may be ordered to confirm the cause, which is suspected on the bases of history and physical examination and audiometry findings: CBC, ESR, tests for syphilis, diabetes, hypothyroidism, blood disorders and lipid profiles, and vestibular tests. 2. Gadolinium-enhanced MRI: It is indicted on the suspicion of acoustic neuroma. Though only 1–3% of SSNHL is due to acoustic neuroma, about 10% of acoustic neuroma patients present with SSNHL. 3. Exploratory tympanotomy: It may be done where perilymph fistula is strongly suspected. Treatment As the cause remains often obscure, treatment also remains empirical. Though corticosteroid therapy is the mainstay, vasodilator, diuretics, anticoagulants and thrombolytic agents have also been tried. In addition to bed rest, treatment consists of the following elements: 1. Steroid therapy: Prednisolone 40–60 mg in a morning dose for 1 week and then tapered off in a period of 3 weeks. Steroids relieve edema as they have anti-inflammatory effect. They are of particular use in hearing loss of moderate degree. 2. Antivirals such as acyclovir. 3. Inhalation of carbogen (5% CO2 + 95% O2): It increases cochlear blood flow and provides better oxygenation. 4. Low molecular weight dextran: The infusions decrease blood viscosity. It is contraindicated in cardiac failure and bleeding disorders. 5. Hyperbaric oxygen therapy: If given in the first month of onset of hearing loss, some benefits have been seen.  Prognosis About 50% patients recover spontaneously within 15 days. Chances of recovery are less after one month. Good prognostic factors: young adults, moderate and low-frequency hearing loss, lack of vertigo and early treatment. Poor prognostic factors: old age, profound deafness, presence of vertigo, vascular risk factors and delayed treatment.  Presbycusis (Age related SNHL) Part of aging process. More than one-third of elderly persons over the age of 75 have this senile hearing loss. Predisposing Factors Though the exact cause is yet not known, following factors have been implicated: hereditary predisposition, chronic noise exposure, vascular risk factors, ototoxicity, metabolism, arteriosclerosis and diet.  Pathology and Audiometry The following four pathological types have been described: 1. Sensory: The degeneration of the organ of Corti begins at the basal coil and progresses gradually toward the apex. So, the higher frequencies are affected first. The speech discrimination remains good. 2. Neural: The degeneration of spiral ganglion begins at the basal coil and progresses towards the apex. Neurons of higher auditory pathways may also be affected. The PTA shows high tone loss. Speech discrimination is poor, which is out of proportion to the pure tone loss. 3. Strial or metabolic: The atrophy of stria vascularis occurs in all turns of cochlea. The physical and chemical processes of energy production are affected. This type of presbycusis pathology runs in families. PTA shows flat graph. Speech discrimination remains good. 4. Cochlear conductive: The stiffening of the basilar membrane affects its own movements. Audiogram is sloping type. I Clinical Features 1. Slowly progressive, symmetric SNHL in people over the age of 60. 2. Background noise: Great difficulty in hearing in the presence of background noise. Patients may hear well in quiet surroundings in early stage of the disease. 3. Discrimination: Poor speech understanding. Typical complaint “I can hear but cannot understand.” 4. Recruitment: Intolerance to loud sounds due to the recruitment. The patient has hearing loss but if someone speaks loudly, she/he retorts “why are you shouting? I am not deaf.” 5. Tinnitus: It may be bothersome and the only complaint. 6. Audiogram (Fig. 5): SNHL is greatest in frequencies > 2,000 Hz with significant decrease in speech discrimination. Treatment Patients are advised for the following: ❖Hearing aid. ❖Lessons in speech reading through visual cues. ❖Curtailment (decrease) of smoking and stimulants like tea and coffee for decreasing tinnitus. Thank you