Diseases of the inner ear

short note on physiology and some clinical cases

1. Diseases of the inner ear Dr. Rahman Aljanabi FEB.ORL-HNS;CABMS;FJBMS KUFA Medical College 2015

2. Introduction Anatomy: The inner ear consist of : 1-the cochlea : concerned with hearing 2-the vestibular apparatus : responsible for equilibrium : A-3 semicircular canals : B- Utricle : C- Sacule :

3. How the body maintain balance .note 1:- normally, the impulses reaching the brain from three systems(vestibular, visual and somatosensory) which are peripheral sensory organ of position that send information to higher center which will analyzed and integrated to maintain position(very complex mechanism involving various reflex arcs and cerebellar and cerebral control) Note 2:- these impulses are equal and opposite so the brain can detect any changes in position by relative difference in impulses between the tow side Note 3 :- there is central compensation for the lack of one of the balance maintain mechanism but this is a time dependent process so the more acute pathology the more patient symptoms and vice versa.

4. Symptoms of inner ear diseases: - Cochlea :----- hearing loss(sensorineural), tinnitus Vestibular system(SCC and vestibule):---- vertigo or unsteadiness Note 1 :- peripheral vestibular system:- include the vestibular apparatus(SCC and vestibule) and vestibular nerve Central vestibular system(within CNS ):starts from vestibular nuclei in the Pons and its central connection(including cerebellum)   Note 2:- body balance is maintained by a complex mechanism involving input data from vestibular, visual, and somatosensory (proprioception) systems that is transmitted to higher center(cerebrum and cerebellum) to be analyzed and integrated to maintain balance Note 3 :-there is central compensation for the lack of one of the balance maintain mechanism but this is a time dependent process so the more acute pathology the more patient symptoms and vice versa e  

5. Causes of peripheral vestibular system Like any organ in the body, the vestibular system can be affect by:- A-Congenital malformation:- but it is a symptomatic as central compensation occur early in infancy B-acquired:- 1-infections:- bacterial or viral ;acute or chronic e.g labrynthitis , vestibular neuritis ,syphilis 2-tumour:- like acoustic neuroma(vestibular schwannoma ) 3-trauma:- temporal bone fracture, perilymph fistula 4-Autoimmune:- autoimmune inner ear diseases 5-vascular:- labyrinthine apoplexy 6-degenerative:- Dysequilibrium of ageing ( presbyastasis ) 7-miscillaneous:- Meniere's disease, benign paroxysmal positional vertigo(BPPV)

6. Vestibular disorders Peripheral (Lesions of end organs vestibular nerve ) • Meniere's disease • Benign paroxysmal positional vertigo • Vestibular neuritis • Labrynthitis • Vestibulotoxic drugs • Head trauma • Perilymph fistula • Syphilis • Acoustic neuroma Central (Lesions of brainstem and central connections ) • Vertebrobasilar insufficiency • Posterior inferior cerebellar artery syndrome • Basilar migraine • Cerebellar disease • Multiple sclerosis • Tumors of brainstem and fourth ventricle • Cervical vertigo Epilepsy

7. Benign Paroxysmal Positional vertigo(BPPV) Its symptoms are repeated attacks(paroxysm) of rotation sensation (vertigo) lasting for seconds caused by changes in the position of the head(positional). the patient is completely normal in between attacks it is the most common cause of the symptoms of vertigo usually associated with nausea and vomiting, no cochlear, no CNS symptom(like loss of consciousness, paresthesia , weakness, cerebellar sign etc)

8. Pathophysiology of BPPV BPPV is a mechanical problem in the inner ear. It occurs when some of the calcium carbonate crystals (otoconia) that are normally embedded in the gel layer of the macula of the utricle become dislodged and migrate into one or more of the 3 1SCC as it is most dependant This floating particle cause stimulation of hair cells of crista of posterior SCC when the head move then rapidly settle

9. BPPV Examination:- nothing significant Dx.:- by Dix-Hallpike maneuver(torsional nystagmus and vertigo(after a latency of 3-10 sec. ,lasting less than 1 min. and fatigue on repeating the test) Cause:- idiopathic but otoconia may dislodge due previous head trauma or aging process etc Treatment:- repositioning the particles of otoconia in the utricle instead of posterior SCC by different maneuver like Epply man. and Semont man. The condition usually resolve spontaneously within a week or few weeks but tend to recur after a period of time  

10. Dix-Hallpike test and Epply maneuver

11. Meniere’s disease Is an inner ear disease characterized by :- Episodic vertigo ,hearing loss ,tinnitus and ear fullness lasting for minutes –days . The disease affect cochlea and SCC and vestibule(whole membranous labyrinth) which reflect its symptoms

12. Pathogenesis Distension of the membranous labyrinth or endolymphatic hydrops is postulated as a cause of this condition either due to excessive production or impair absorption of endolymph

13. Meniere’s disease The attack occurs due to small ruptures in Reissner membrane leading to mixing of the endolymph and perilymph .

14. Meniere’s disease Clinical features The duration of the vertigo last usually for 30 minutes to 4 hours 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.

15. 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

16. Over the course of the disease hearing loss and tinnitus become permanent The disease is usually unilateral initially but can become bilateral Sign:- spontaneous rotatory nystagmus Investigations:- P.T.A. , brain MRI may be needed to role out central causes

17. Meniere's ‘s disease Treatment:- In acute phase :- treatment consists of vestibular sedative(stugerone, anti-emetics), Betahistine(betaserc) ,diuretics In long term :-avoidance of caffeine and salt and reassurance can reduce the number of the attacks and increase the patient ability to cope with the attacks

18. Meniere’s disease Ablation therapy:- Gentamycin is given through the tympanic membrane will be absorbed through the round window and selectively damage the vestibular cells relative to the cochlear cells

19. Meniere’s disease 2- Surgical Treatment:- rarely needed A. Endolymphatic sac surgery: By transmastoid approach c h the endolymaphatic sac either decompressed or a shunt is placed in the sac that communicate s with the subarachnoid space or mastoid cavity B-Vestibular nerve section:- in patients with serviceable hearing C-labyrinthectomy : - in patients with unilateral Meniere’s disease and poor hearing y.

20. Vestibular neuritis Is a viral infection of the vestibular nerve

21. Vestibular neuritis Etiology:- most likely due to viral infection supported by polymerase chain reaction to detect viral DNA In postmortem study mostly Herpes simplex virus type one Symptoms:- acute spontaneous vertigo associated with nausea and vomiting lasting from days –weeks, no cochlear involvement, no CNS The symptoms subside over the following days but many patients have residual imbalance that last for months . Hearing is normal Sign:- Acute attack there is nystagmus (horizontal towards the unaffected side ) After acute stage passed, nystagmus disappear but patient characteristically rotate towards the affected side when attempt to march on a spot with their eyes closed positive Unterberger test

22. Vestibular neuritis Ix:- PTA ,brain MRI may be needed if central vertigo can not be excluded easily Treatment :- acute stage:-bed rest , vestibular sedative , steroids can be used to shorten the course of the disease Antiviral?? Resolution stage:-after vertigo subsides (vestibular rehabilitation exercise) will enhance central compensation(as it is a paretic pathology)

23. Traumatic inner ear disease(Temporal bone fractures 20 % of skull base fractures Etiology : 1-RTA 2-Blunt trauma to the lateral surface of the skull Classification : 1-longitudinal fractures 80 -90 % 2-transverse fractures 10- 20%

24. 1-longitudinal fractures

25. transverse fractures

26. Longitudinal fracture Usually spare the labyrinth and facial nerve The fracture line involves the external meatus and the roof of the of the middle ear . Bleeding in the middle ear(heamotympanum) ,ossicular chain disruption, tympanic membrane may be perforated Bloody otorrhea (even CSF )occur if TM is perforated and Deafness usually conductive type Facial palsy is uncommon Battle’s sign :ecchymosis in the postauricular area

27. Battle sign Haemotympanum

28. 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 .

29. Treatment Management :- multitrauma patient with head trauma For fracture itself- -conservative plus broad spectrum antibiotic Vertigo--- vestibular sedative Haemotympanum ---- conservative treatment usually resolves within 3-4 weeks Tympanic membrane perforation- --- usually heals within 3 months if persists then myringoplasty

30. 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 medical treatment fail

31. Acoustic trauma : Acute acoustic trauma may arise from sudden very loud sound as in explosion The effects Sensorineural hearing loss (most common ) Conductive deafness due to tympanic membrane rupture or damage to the middle ear .

32. Noise induced hearing loss Chronic noise induced hearing loss results fro long term exposure to loud sounds As in heavy industry workers Tinnitus is a prominent feature in this condition and the audiogram has a classical appearance with a dip at 4 khz .