Labyrinthitis.pptx

Labyrinthitis is inflammation of inner ear

1. Mansi Dhaketa Group 9626 m2a Medicine Otorhinolaryngology Labyrinthitis

2. Background Labyrinthitis is an inflammatory disorder of the inner ear, or labyrinth. Clinically, this condition produces disturbances of balance and hearing to varying degrees and may affect one or both ears. Bacteria or viruses can cause acute inflammation of the labyrinth in conjunction with either local or systemic infections. Autoimmune processes may also cause labyrinthitis. Vascular ischemia may result in acute labyrinthine dysfunction that mimics labyrinthitis.

3. Path physiology The labyrinth is composed of an outer osseous framework surrounding a delicate, membranous network that contains the peripheral sensory organs for balance and hearing. These sensory organs include the utricle, saccule, semicircular canals, and cochlea. Symptoms of labyrinthitis occur when infectious microorganisms or inflammatory mediators invade the membranous labyrinth and damage the vestibular and auditory end organs. The labyrinth lies within the petrous portion of the temporal bone adjacent to the mastoid cavity and connects with the middle ear at the oval and round windows. The labyrinth maintains connections with the central nervous system (CNS) and subarachnoid space by way of the internal auditory canal and cochlear aqueduct. Bacteria may gain access to the membranous labyrinth by these pathways or through congenital or acquired defects of the bony labyrinth. Viruses may spread to labyrinthine structures hematogenously or by way of the aforementioned preformed pathways.

4. Etiology Viral labyrinthitis Rubella and cytomegalovirus are the best-recognized viral causes of prenatal hearing loss.Viral infections are also implicated in idiopathic, sudden sensorineural hearing loss (SNHL). Bacterial labyrinthitis Bacterial labyrinthitis is a potential consequence of meningitis or otitis media and may occur by either direct bacterial invasion (suppurative labyrinthitis) or through the passage of bacterial toxins and other inflammatory mediators into the inner ear (serous labyrinthitis). Suppurative labyrinthitis In patients with meningitis, bacteria can spread from the cerebrospinal fluid to the membranous labyrinth by way of the internal auditory canal or cochlear aqueduct. Bacterial infections of the middle ear or mastoid most commonly spread to the labyrinth through a dehiscent horizontal semicircular canal. Serous labyrinthitis Serous labyrinthitis occurs when bacterial toxins and host inflammatory mediators, such as cytokines, enzymes, and complement, cross the round window membrane, causing inflammation of the labyrinth in the absence of direct bacterial contamination.

5. Potential viral causes of labyrinthitis include the following: Cytomegalovirus Mumps virus Varicella-zoster virus Rubeola virus Influenza virus Parainfluenza virus Rubella virus Herpes simplex virus 1 Adenovirus Coxsackievirus Respiratory syncytial virus Potential bacterial causes of labyrinthitis include the following: Streptococcus pneumoniae Haemophilus influenzae Moraxella catarrhalis Neisseria meningitidis Streptococcus species Staphylococcus species Proteus species Bacteroides species Escherichia coli Mycobacterium tuberculosis

6. Labyrinthitis Clinical Presentation History A thorough medical history, including symptoms, past medical history, and medications, is essential to diagnosing labyrinthitis as the cause of the patient's vertigo or hearing loss. Symptoms to consider in the patient’s medical history include the following: Vertigo - Timing and duration, association with movement, head position, and other characteristics Hearing loss - Unilateral or bilateral, mild or profound, duration, and other characteristics Aural fullness Tinnitus Otorrhea Otalgia Nausea or vomiting Fever Facial weakness or asymmetry Neck pain/stiffness Upper respiratory tract infection symptoms - Preceding or concurrent Visual changes The patient’s past medical history should be examined for the following: Episodes of dizziness or hearing loss Infections Sick contacts Ear surgery Hypertension/hypotension Diabetes Stroke Migraine Trauma (head or cervical spine) Family history of hearing loss or ear disease

7. Viral labyrinthitis Viral labyrinthitis is characterized by a sudden, unilateral loss of vestibular function and hearing. The acute onset of severe, often incapacitating, vertigo, frequently associated with nausea and vomiting, is characteristic of this disorder. The patient is often bedridden while the symptoms gradually subside. Vertigo eventually resolves after several days to weeks; however, unsteadiness and positional vertigo may persist for several months. Hearing loss is common and may be the primary presenting symptom in many patients. An upper respiratory tract infection precedes the onset of cochleovestibular symptoms in up to 50% of cases. Recurrent attacks are reported but are rare and may be confused with Ménière disease. Resolution of vertigo and dysequilibrium is common and is due to partial recovery of vestibular function, with concurrent central compensation of the remaining unilateral vestibular deficit. Return of hearing usually mirrors the return of vestibular function.

8. A unique form of viral labyrinthitis is the aforementioned herpes zoster oticus, or Ramsay-Hunt syndrome . The cause of this disorder is reactivation of a laten t varicella-zoster virus infection occurring years after the primary infection. Evidence suggests that the virus may attack the spiral and vestibular ganglion in addition to the cochlear and vestibular nerves. The initial symptoms of herpes zoster oticus are deep, burning, auricular pain followed a few days later by the eruption of a vesicular rash in the external auditory canal and concha. Vertigo, hearing loss, and facial weakness may follow singly or collectively. Symptoms typically improve over a few weeks; however, patients often suffer permanent hearing loss and persistent reduction of caloric responses.

9. Physical Examination The physical examination includes a complete head and neck examination, with emphasis on the otologic, ocular, and cranial nerve portions of the examination. A brief neurologic examination is also necessary. Seek the presence of meningeal signs if meningitis is a consideration. The otologic examination should be carried out as follows: Perform an external inspection for signs of mastoiditis, cellulitis, or prior ear surgery Inspect the ear canal for otitis externa, otorrhea, or vesicles Inspect the tympanic membrane and middle ear for the presence of perforation, cholesteatoma, middle ear effusion, or acute otitis media The ocular examination should be performed as follows: Inspect the ocular range of motion and pupillary response Perform a funduscopic examination to assess for papilledema Observe for nystagmus (spontaneous, gaze-evoked, and positional); perform a Dix-Hallpike test if the patient can tolerate it If visual changes are suggested, consult an ophthalmologist The neurologic examination should be performed as follows: Perform a complete cranial nerve examination Assess for balance using the Romberg test and tandem gait Assess cerebellar function by performing finger-to-nose and heel-to-shin tests

10. Diagnostic Considerations Vestibular neuritis Viral labyrinthitis is often confused with vestibular neuritis, and the terms are occasionally used interchangeably in the literature. However, most authors agree that vestibular neuritis is a disorder of the vestibular nerve and is not associated with hearing loss. Because the cochlea is affected in pan-labyrinthine inflammation, hearing loss is always present in persons with viral labyrinthitis. Vestibular neuritis typically manifests as sudden, acute vertigo without hearing loss in an otherwise healthy patient. The condition is more common in the fourth and fifth decades of life and affects men and women equally. An upper respiratory tract infection often precedes the condition, and the disorder is more common in the spring and early summer. Histopathologic nerve studies of patients with vestibular neuritis demonstrate axonal loss, endoneurial fibrosis, and atrophy. These findings are consistent with a viral inflammatory etiology. The treatment of vestibular neuritis and viral labyrinthitis is similar.

11. Other conditions Noninfectious labyrinthitis is very rare in children; therefore, seek an alternative diagnosis in patients this age. Labyrinthitis resulting from otitis media or meningitis is not uncommon in children. Conditions to consider in the differential diagnosis of labyrinthitis also include the following: Vertebrobasilar insufficiency Presyncopal dizziness Cerebellar infarct Dysequilibrium of aging Drug-induced vertigo and/or hearing loss

12. Imaging Studies CT scanning Consider a computed tomography (CT) scan prior to lumbar puncture in cases of possible meningitis. A CT scan is also useful to help rule out mastoiditis as a potential cause. A temporal bone CT scan may aid in the management of patients with cholesteatoma and labyrinthitis. A noncontrast CT scan is best for visualizing fibrosis and calcification of the membranous labyrinth in persons with chronic labyrinthitis or labyrinthitis ossificans. MRI Magnetic resonance imaging (MRI) can be used to help rule out acoustic neuroma, stroke, brain abscess, or epidural hematoma as potential causes of vertigo and hearing loss. Vestibular Testing Caloric testing and an electronystagmogram may help in diagnosing difficult cases and establishing a prognosis for recovery. Evidence suggests that careful evaluation of the vestibulo-ocular reflex may help to establish the etiology of the labyrinthitis.

13. Labyrinthitis Treatment & Management Viral labyrinthitis The initial treatment for viral labyrinthitis consists of bed rest and hydration. Most patients can be treated on an outpatient basis. However, they should be cautioned to seek further medical care for worsening symptoms, especially neurologic symptoms (eg, diplopia, slurred speech, gait disturbances, localized weakness or numbness). Patients with severe nausea and vomiting may benefit from intravenous (IV) fluid and antiemetic medications. Diazepam or other benzodiazepines are occasionally helpful as a vestibular suppressant. A short course of oral corticosteroids may be helpful. Currently, the role of antiviral therapy is not established. In a randomized, controlled trial by Strupp et al, steroids (methylprednisolone) w ere found to be more effective than antiviral agents (valacyclovir) for recovery of peripheral vestibular function in patients with vestibular neuritis. The antiviral drugs acyclovir, famciclovir, and valacyclovir shorten the duration of viral shedding in persons with herpes zoster oticus and may prevent some auditory and vestibular damage if started early in the clinical course. Administer corticosteroids to reduce inflammation and edema in the facial canal and labyrinth.

14. Bacterial labyrinthitis For bacterial labyrinthitis, antibiotic treatment is selected based on culture and sensitivity results. Treatment of suppurative labyrinthitis is aimed at eradicating the underlying infection, providing supportive care to the patient, draining middle ear effusions or mastoid infections, and preventing the spread of infection.

15. Prognosis The acute symptoms of vertigo and nausea and vomiting resolve after several days to weeks in all forms of labyrinthitis; however, hearing loss is more variable. Suppurative labyrinthitis nearly always results in permanent and profound hearing loss, whereas patients with viral labyrinthitis may recover from hearing loss. Dysequilibrium and/or positional vertigo also may be present for weeks following resolution of the acute infection.

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