Labyrinthitis is an inflammatory disorder of the inner ear that causes disturbances in balance and hearing. It can be caused by bacterial or viral infections invading the delicate structures of the inner ear. Patients experience vertigo, hearing loss, nausea, and imbalance. A physical exam evaluates ear function, eye movements, and neurological signs. Diagnostic tests like CT, MRI and vestibular testing help identify the cause and rule out other conditions. Treatment focuses on resolving the underlying infection with antibiotics or antivirals, and managing symptoms with rest, hydration and medications. Hearing loss outcomes vary depending on the cause, but balance symptoms typically improve over weeks with recovery of vestibular function.

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 latent 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.

12. 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

13. 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.

14. 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) were 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.

15. 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.

16. 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.

17. Thank you¡