Ear - Chapter 6 (Diseases of the inner ear) Flashcards
Meniere’s disease definition, c/p, investigations and ttt?
- Distention of the membranous labyrinth due to increased volume of the endolymph i.e endolymphatic hydrops.
- Common cause of peripheral labyrinthine vertigo.
- Age : 20-50 years.
- Unilateral, but may become bilateral.
Etiology :
Unknown : either.
* Decreased endolymph absorption by the endolymphatic sac.
* Increased endolymph production due to increased capillary permeability as a result of endocrinal disturbance, autoimmune disturbance, sympathetic over-activity or allergy.
Clinical picture :
Recurrent sudden attacks of a triad of symptoms : vertigo, hearing loss and tinnitus. Each attack lasts for several minutes to several hours.
* Vertigo is usually associated with nausea, vomiting and sweating between the attack, the patient is completely free.
* Sensori-neural hearing loss and tinnitus are initially reversible (i.e fluctuant hearing loss), but later on they become permanent and progressive.
Investigations :
* Pure tone audiometry : Sensorineural hearing loss, affects the low tones and is reversible. Later on affects all tones and is irreversible.
* Nystagmography : Reduced caloric response on the affected side.
Treatment :
* Medical treatment : most cases are controlled by medical treatment :
- Diuretics and salt restriction to decompress the labyrinth.
- Antivertigal e.g. betahistine (acts as labyrinthine vasodilators improving the blood flow in micro circulation of the labyrinth).
- Sedative during acute attack.
* Surgical treatment: after failure of medical treatment :
- When the hearing is not serviceable e.g dead ear, we destroy the membranous labyrinth (Labyrinthectomy).
- When the hearing is serviceable i.e. good :
o Decompression of the endolymphatic sac to improve endolymph absorption.
o Vestibular neurectomy.
Congenital anomalies of the inner ear with diagnosis and treatment?
Etiology :
(A) Genetic :
* Aplasia : absence of membranous labyrinth.
* Heredodegenerative : tendency for progressive cochlear degeneration to occur in childhood e.g Alports’ syndrome.
* Chromosomal aberration.
(B) Non genetic :
1- Prenatal :
* Diseases occurring during pregnancy : german measles and other virus infections (toxaemia of pregnancy, diabetes and nephritis).
* Drugs taken during pregnancy (aminoglycoside and salicylates).
2- Natal : Prematurity or birth trauma.
3- Post natal :
* Haemolytic diseases e.g (kernicterus) from RH incompatibility between infant if RH +ve and mother if RH –ve.
* Infectious diseases e.g measles, mumps and meningitis.
Diagnosis :
Should be before the age of one year because a child who fail to hear early will not able to talk (deaf-mute).
(A) History: taken from the parents :
* We should ask about diseases during pregnancy, drug taken, consanguinity of the parents, birth trauma, prematurity and infectious diseases affecting the child.
* The main reason for suspecting deafness : failure to respond to sounds, lack of awareness, failure to talk or defective speech.
(B) Audiological evaluation :
* Pure tone and speech audiometery.
* ABR
(C) Neuropediatric and psychological evaluation : e.g LQ to exclude mental retardation which causes diminished response to sound leading to misdiagnosis of deafness.
Treatment :
* Special schools for these children.
* For partial deafness : hearing aid.
* For total deafness : lip-reading.
* Cochlear implant may give satisfactory result in some bilateral cases.
Inner ear traumas (Acoustic trauma imp)
1- Surgical trauma :
* Mechanical, acoustic or thermal during mastoid surgery while using the electric bur.
* During stapedectomy.
2- Temporal bone fracture : Transverse fracture (mentioned before in trauma of the middle ear).
3- Head and neck trauma (without fracture) : This is due to labyrinthine concussion, sensorineural hearing loss and positional vertigo.
4- Diving injuries :
* Leads to transient or permanent sensorineural hearing loss and vestibular symptoms.
* This may be due to labyrinthine hemorrhage, rupture of windows membrane or excess noise exposure.
* Inner ear barotrauma : increased perilymph pressure during descent with locked Eustachian tube, and increased middle ear pressure during ascent will lead to rupture of round or oval windows membrane resulting in sensorineural hearing loss.
5- Acoustic trauma :
A- Acute :
Perceptive deafness due to very brief exposure to very loud sound.
Etiology :
* Gunfire.
* Explosions.
Clinical picture :
* Sensorineural hearing loss which is usually permanent. The hearing loss is maximum at 5500 Hz.
Treatment :
* Medical treatment e.g cortisone and vasodilators.
* Hearing aid.
* Cochlear implants may be of help in some bilateral cases.
B- Chronic :
Noise induced hearing loss : Perceptive deafness due to prolonged exposure to loud noise.
Etiology :
* Some individuals are more susceptible than others.
* Continued exposure to noise above 85 dB e.g some factories.
Clinical picture :
S.N.H.L which is reversible in the early stage then becomes permanent. The hearing loss is maximum at 4000 Hz (basilar membrane is more rigid and susceptible to trauma).
Treatment :
* Preventive, most important in the early stages.
* Screening of personnel in noisy occupations.
* Resting and rehabilitation of personnel complaining of early symptoms.
6- Radiotherapy :
May affect the ear in two ways :
* Eustachian tube edema or fibrosis causing conductive deafness.
* Perceptive deafness which may be gradual and delayed (it is related to the dose).
7- Electricity :
May affect the ear in two ways :
* Rupture tympanic membrane causing conductive deafness.
* Perceptive deafness (usually recoverable).
Acoustic neuroma definition, c/p, investigations and treatment ?
- A Benign tumor, which arises from Schwann cells (sheath) of the vestibular division of the vestibulocochlear nerve.
- It starts in the internal auditory canal then spreads to the cerebellopontine angle.
Clinical Picture :
* Otological manifestations (tumor within the internal auditory canal) :
- Unilateral tinnitus and sensorineural hearing loss.
- Vertigo not marked as tumors grows slowly so central compensation takes place.
- Facial n. paralysis late with a big tumor.
* Neurological manifestation (tumor extending into cerebellopontine angle) :
- Cranial nerves (V, IX, X, XI, and XII) palsies. The earliest is the trigeminal (loss of corneal reflex).
- Cerebellar manifestation.
- Increased intracranial tension – late.
Investigation :
* Audiological examination :
- Pure tone audiometry : unilateral sensori-neural hearing loss.
- Speech audiometry : poor speech discrimination.
- Auditory brain stem response (ABR) : highly suggestive.
* Nystagmography : Reduced caloric response on the affected side.
* CT scan and MRI (most accurate and most diagnostic).
Treatment :
* Small tumors: with mild deafness: Excision through middle fossa approach.
* Large tumors: with sever deafness: Excision via translabyrinthine approach.
* Huge tumors are removed through sub occipital approach.
Presbycusis definition, c/p and ttt?
- Senile hearing loss.
- Hearing loss due to degeneration of the cochlear sensory end organ due to aging.
- The commonest cause of SNHL in adults.
Clinical picture :
* Bilateral SNHL and tinnitus.
Treatment :
* Auditory rehabilitation (hearing aid) if necessary.
Ototoxicity definition, c/p and ttt?
Definition :
Degeneration of the labyrinthine sensory end organ “both cochlear and vestibular” due to drugs.
Drugs which causes ototoxicity :
* Aminoglycosides “streptomycin, gentamycin, tobramycin, neomycin,
kanamycin, ….etc.
* Diuretics as frusemide “lasix”.
* Cytotoxic drugs.
* Quinines.
* Salicylate (the risk increases in case of poor kidney function).
Clinical picture :
1- Prophylactic treatment :
* Avoid ototoxic drugs as much as possible.
* Regular monitoring of hearing and drug serum level.
* Immediate withdrawal when any manifestation of ototoxicity develops e.g with streptomycin sulfate vertigo precedes hearing loss, so if the patient starts to suffer from vertigo stop the drug.
N.B : Streptomycin dihydrochloride affect the cochlear labyrinth before the vestibular labyrinth, therefore hearing loss precedes vertigo. While streptomycin sulfate affects the vestibular labyrinth before the cochlea, therefore vertigo precedes hearing loss.
2- Vestibular sedatives.
3- Auditory rehabilitation e.g hearing aid if applicable
Pain local and referred causes?
1- Local causes :
a- External ear :
* Trauma, inflammation (otitis externa) and cancer external canal.
* Pain increased on mastication, on moving the auricle or pressure on the tragus.
b- Middle ear :
* Traumatic rupture of tympanic membrane
* Inflammation (acute otitis media, complicated chronic suppurative otitis media e.g mastoiditis, extradural abscess and lateral sinus thrombosis
* Otitic barotrauma
* Cancer.
* Pain may be increased by coughing and sneezing due to increased intratympanic Pressure.
c- Inner ear :
No pain sensory fibers in the inner ear.
2- Referred pain :
From areas sharing the same nerve supply with the ear
* 5th cranial nerve (Auriclo temporal nerve)
- Dental caries and impacted wisodom tooth.
- Sinusitis.
- Salivary gland disorders.
- Trigeminal neuralgia.
- TMJ disorders.
* 9th cranial nerve (Jacobson nerve)
- Post tonsillectomy.
- Quinzy.
- Ulcers and carcinoma of the base of the tongue.
- Glossopharyngeal neuralagia.
* 10th cranial nerve (Arnold nerve)
- Cancer larynx.
- T.B. laryngitis.
- Cancer esophagus.
* 2nd and 3rd cervical nerves :
- Arthritis of the cervical spines.
- Cervical lymphadenitis.
- Myositis of the neck muscles.
* 7th cranial nerve :
- Bell’s palsy.
- Ramsy-Hunt syndrome.
Conductive hearing loss causes
Definition: due to lesion in the conductive system of sound (External ear and middle ear).
Causes :
a- Congenital :
- Congenital atresia of the external auditory canal.
- Congenital anomalies of the ossicles.
b- Traumatic :
- Impacted F.B or wax in the external auditory canal.
- Traumatic rupture of the tympanic membrane.
- Ossicular disconnection.
- Hemotympanum in fracture base of skull.
- Otitic barotraumas.
c- Inflammatory :
- Otitis externa (big furuncle or fungus).
- Otitis media (suppurative and non-suppurative).
d- Neoplastic :
- Exostosis and carcinoma of the external auditory canal.
- Glomus tumour and carcinoma of the middle ear.
e- Miscellaneous :
- Eustachian dysfunction.
- Otosclerosis.
N.B. :
- The most common cause is wax (wax pushed against the tympanic
membrane with a cotton bud, or embibing water e.g shower or
swimming is the most common cause of sudden and flactuant
(conductive) deafness.
- The most common cause of bilateral conductive hearing loss is
secretory otitis media.
Sensorineural hearing loss definition and causes?
Perceptive deafness is caused by diseases of the cochlea (sensory H.L), cochlear nerve (neural H.L) and central connections (central H.L). The cochlear conditions are the most common.
A- Inner ear :
Causes :
o Congenital : Deafness in children (mentioned later).
o Traumatic :
- Fracture base involving the labyrinth (Transverse type).
- Acoustic trauma.
- Noise-induced hearing loss.
- Surgical trauma e.g stapedectomy, mastoidectomy or tympanoplasty.
o Inflammatory :
- Labyrinthitis as a complication of suppurative otitis media.
- Labyrinthitis as a complication of infectious diseases :
* Viral e.g measles, mumps and influenza.
* Bacterial e.g meningitis, typhonic, T.B and syphilis.
o Toxic :
- Ototoxic drugs e.g streptomycin, kanamycin, neomycin, quinine and diuretics, usually affects the stria vascularis.
o Metabolic :
- Diabetes, renal or hepatic failure.
o Miscellaneous :
- Senile deafness (presbycusis) : The most common cause of SNHL.
- Meniere’s disease.
- Cochlear otosclerosis.
- Deafness
B- Cochlear nerve : Acoustic neuroma.
C- Brainstem and cerebral cortex :
o Multiple sclerosis.
o Vertebrobasilar insufficiency.
o Brain tumours.
Mixed hearing loss causes ?
- Congenital meatal atresia with I.E anomaly. (Inner ear)
- Chronic suppurative O.M with labyrinthitis.
- Combined otosclerosis.
The difference between conductive H.L and SNHL?
A) General examination :
* History of ear discharge, ototoxic drugs.
* Speech discrimination (good in cond. H.L poor in SNHL).
* A shout causes distress in sensory H.L due to recruitment (increase sensitivity to loud sound) in contrast to good tolerance to loud sound in C.H.L.
B) ear examination : wax, drum perforation.
C) Hearing tests :
* Tuning fork test
* Audiometry
Tuning fork tests :
Sound is heard through 2 routes :
* Air conduction: from the ext. meatus to middle ear then to the cochlea.
* Bone conduction through the skull bone directly to the cochlea.
* Tuning fork tests (mentioned in the audiology part).
Audiometry :
Demonstrate the type and degree of hearing loss.
Types
a- Subjective: needs active cooperation of the patient.
* Pure tone audiometry.
* Speech auditomentery.
b- Objective: does not needs cooperation of the patient so it is important to test malingering
Management of Hearing loss :
* Treatment of the cause: medical or surgical.
* Hearing rehabilitation : hearing aid or cochlear implant (mentioned later).
Sudden sensorineural hearing loss definition, causes, investigations and ttt?
Means acute SNHL that becomes instantly apparent or rapidly developed over a period of hours or a few days (less than 3 days).
Incidence :
* Unilateral or bilateral, always unilateral.
Etiology :
1- Causes in the inner ear :
* Idiopathic (the most common cause) :
- Considered to be due to vascular “spasm, hemorrhage, thrombosis or embolism” or viral “e.g Post-influenza”.
* Traumatic :
- Physical e.g acute acoustic trauma or rupture labyrinthine membranes (perilymph fistula).
- Mechanical : transverse fracture of temporal bone.
- During stapedectomy.
* Infections :
- Viral : measles, mumps or influenza.
- Bacterial : meningitis.
* Toxic : Ototoxic drugs.
* Meniere’s disease may present with sudden SNHL.
2- Causes in the vestibulocochlear nerve :
* Inflammation.
* Trauma.
* Tumors as acoustic neuroma : 10% of cases of acoustic neuroma present with sudden SNHL.
Investigations :
* Audiological assessment : pure tone audiometry, speech audiometry and ABR (auditory brainstem response).
* MRI to exclude acoustic neuroma.
* Investigations to detect other causes.
Treatment :
1- Should be started as early as possible because early treatment has good prognosis.
2- If we find a definite cause e.g Perilymph fistula treat the cause.
3- If we do not find a definite cause “majority of cases” consider as idiopathic “vascular and viral”. There are many regimens for treatment which include corticosteroids, vasodilators, anticoagulants and inhalation of 5% CO2 + 95% O2 mixture.
4- Intratympanic corticosteroid injection.
If the above measures fail, auditory rehabilitation e.g Hearing aid may be needed if necessary.
Fluctuant hearing loss definition and causes?
Hearing loss that improves a little, then becomes worse again and so on, may be due to :
1- Secretory otitis media, it is conductive deafness.
2- Meniere’s disease, is a well known cause of fluctuating hearing loss, the hearing is worse during the attack and improves a little after the episode is over.
3- Rupture of the round window (R.W) membrane, this is called perilymph fistula.
4- Wax in the external canal, when gets wet after shower or swimming, the blockage is more tight and hearing diminished, and when dry it shrinks and hearing improves.
5- Intermittent otitis media, with or without perforation.
6- Autoimmune deafness.
ear discharge (Otorrhea) causes?
Watery discharge (C.S.F) :
1- Fracture base involving the middle ear with tear in the dura (longitudinal fracture).
2- Surgical trauma involving the dura (mastoidectomy) or the membranous labyrinth (stapedectomy).
3- After skull base surgery.
Bloody discharge :
1- Traumatic :
* Fracture base of the skull (long fracture).
* Injury of the external ear.
* Tympanic membrane perforation.
2- Inflammatory :
* Bullous myringitis.
* Chronic otitis media with granulations.
* Malignant otitis externa.
3- Neoplastic :
* Rodent ulcer or carcinoma of external ear.
* Glomus tumour or carcinoma of middle ear.
Mucoid or mucopurulent discharge :
Suppurative otitis media (Tubotympanic type).
Purulent discharge :
1- Furunculosis (the discharge is scanty, cheesy never mucoid).
2- Cholesteatoma (the discharge is scanty and fetid).
3- +ve reservoir sign : recollection of pus after suction from external canal, it is a sign of acute mastoiditis.
Serous discharge :
Eczematous otitis externa.
TINNITUS definition, types, causes and management?
Definition :
Sensation of noise or sound in the ear or the head in the absence of external stimulation.
Nature:
* Unilateral or bilateral.
* May be ringing, whistling , humming or pulsating.
Types :
* Subjective: heard only by the patient.
* Objective : heard by the patient and the examiner (by auscultation of the ear and skull).
Pathogenesis :
Lesion of the hearing, vascular or muscular system.
Causes :
1- Tinnitus with hearing loss = due to local causes in the ear :
a- Tinnitus with cond. H.L (causes of cond. H.L).
b- Tinnitus with perceptive H.L (causes of SNHL).
2- Tinnitus without H.L. = due to causes outside the ear :
a- Subjective tinnitus: due to hyperdynamic circulation :
* Hypertension, hypotension.
* Thyrotoxicosis
* Anaemia
* Fevers
N.B. : T.M.J arthritis, impacted wisdom tooth may cause tinnitus.
b- Objective tinnitus :
* Vascular :
- Intracranial vascular tumors.
- Arteriovenous malformation.
- Aneusysm of internal carotid artery.
* Muscular colonic contraction of intratympanic or palatal muscles.
N.B. : Pulsatile tinnitus due to glomus, high jugular bulb or carotid aneurysm.
Management :
* Investigation: Audiological, CT scan and Angiography.
* Treatment of the cause.
* Tinnitus maskers.
