AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

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 infection or systemic infection.

Pathophysiology

The anatomic relationships of the labyrinth, middle ear, mastoid, and subarachnoid space are essential to understanding the pathophysiology of labyrinthitis. 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 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 typically spread to labyrinthine structures hematogenously or by way of the aforementioned preformed pathways.

Viral and bacterial labyrinthitis are sufficiently different to warrant discussing them as separate disease processes. 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 also present and may be the primary presenting symptom in many patients. Physical examination findings include spontaneous nystagmus toward the unaffected side with diminished or absent caloric responses in the affected ear. The hearing loss is usually mild to moderate and typically evident in the higher frequencies (>2000 Hz), although any degree or type of hearing loss may be present. 

An upper respiratory tract infection precedes the onset of symptoms in up to 50% of cases. Recurrent attacks are reported but are rare and may be confused with Ménière disease. Resolution of the 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. 

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 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 person. 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. 

A unique form of viral labyrinthitis is 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. The initial symptoms 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 in insolation or collectively. Symptoms typically improve over a few weeks; however, patients often suffer permanent hearing loss and persistent reduction of caloric responses. 

Viral infections can cause both congenital and acquired hearing loss. Rubella and cytomegalovirus are the best-recognized viral causes of prenatal hearing loss. Virally induced hearing loss in the postnatal period is usually due to mumps or measles. Viral infections are also implicated in idiopathic sudden sensorineural hearing loss (SNHL). These topics are covered in other articles (see Pediatrics, Measles; Pediatrics, Mumps; Cytomegalovirus Infection; Pediatrics, Rubella. 

Meningitis and otitis media may be complicated by bacterial labyrinthitis, which can 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). Meningitis typically affects both ears, whereas otogenic infections typically cause unilateral symptoms. Bacteria spread from the cerebrospinal fluid to the membranous labyrinth by way of the internal auditory canal or cochlear aqueduct. Infections of the middle ear or mastoid most commonly spread to the labyrinth through a dehiscent horizontal semicircular canal. Usually, the dehiscence is the result of erosion by a cholesteatoma.

Suppurative labyrinthitis resulting from otitis is uncommon in the postantibiotic era. When suppurative labyrinthitis occurs, it almost always is associated with cholesteatoma. Profound hearing loss, severe vertigo, ataxia, and nausea and vomiting are common symptoms of bacterial labyrinthitis. 

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. Labyrinthitis ossificans often follows suppurative labyrinthitis. In these cases, therefore, decisions regarding cochlear implantation must be made early. Meningitis also may result in progressive hearing loss secondary to necrosis and fibrosis of the membranous cochlea and labyrinth. 

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. This condition is associated with acute or chronic middle ear disease and is believed to be one of the most common complications of otitis media. Toxins, enzymes, and other inflammatory products infiltrate the scala tympani, forming a fine precipitate just medial to the round window membrane. Penetration of the inflammatory agents into the endolymph at the basilar turn of the cochlea results in a mild high-frequency SNHL. Audiography testing reveals mixed hearing loss when a middle ear effusion is present. Vestibular symptoms may occur but are less common. Treatment is aimed at eliminating the underlying infection and clearing the middle ear space of effusion. The hearing loss is usually transient but may persist if the otitis is left untreated.

Frequency

United States

Viral labyrinthitis is the most common form of labyrinthitis observed in clinical practice. One study reported that 37 of 240 patients who presented with positional vertigo had viral labyrinthitis. The prevalence of sudden SNHL is estimated at 1 case in 10,000 persons, with up to 40% of these patients complaining of vertigo or dysequilibrium.¹ Auditory and vestibular symptoms develop in approximately 25% of patients with herpes oticus, in addition to the facial paralysis and vesicular rash that characterize the disease. Bacterial labyrinthitis is rare in the postantibiotic era, although bacterial meningitis remains a significant cause of hearing loss. Auditory symptoms, vestibular symptoms, or both may be present in as many as 20% of children with meningitis.²

Mortality/Morbidity

Deaths associated with labyrinthitis are not reported except in cases of meningitis or overwhelming sepsis. The morbidity of labyrinthitis, especially bacterial labyrinthitis, is significant. In the pediatric population, the risk of hearing loss secondary to meningitis is estimated to be 10-20%.^{2, 3} Streptococcus pneumoniae appears to be the causative agent most likely associated with hearing loss, although some studies place Neisseria meningitidis as the most significant agent.² Bacterial labyrinthitis, regardless of etiology, accounts for one third of all cases of acquired hearing loss. One study reported dizziness in 23% of patients following pneumococcal meningitis. Ménière disease may follow an episode of suppurative or serous labyrinthitis and is most likely due to fibrosis of the endolymphatic sac and altered Na⁺/K⁺ transport.¹

Age

Viral labyrinthitis is usually observed in adults aged 30-60 years and is rarely observed in children. Meningogenic suppurative labyrinthitis is usually observed in children younger than 2 years, which is the population most at risk for meningitis. Otogenic suppurative labyrinthitis can be observed in persons of any age in the presence of cholesteatoma and in untreated acute otitis media.⁴ Serous labyrinthitis is more common in the pediatric age group, in which the vast majority of both acute and chronic otitis media cases are observed.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

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
• • 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
• Past medical conditions
• • 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
• Medications
• • Aminoglycosides and other ototoxic medications
  • Beta-blockers and other antihypertensives
  • Tranquilizers, including benzodiazepines
  • Antiepileptics
  • Illicit drugs

Physical

In the physical examination include 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.  

• Otologic examination
• • 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.
• Ocular examination
• • 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.
• Neurologic examination
• • 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.

Causes

Little direct evidence suggests a viral cause for labyrinthitis; however, a wealth of epidemiologic evidence implicates a number of viruses as potentially causing inflammation of the labyrinth. Viral labyrinthitis is often preceded by an upper respiratory tract infection and occurs in epidemics. The histologic finding of axonal degeneration in the vestibular nerve suggests a viral etiology for vestibular neuritis.¹ The bacteria that cause labyrinthitis are the same bacteria responsible for meningitis and otitis. Gram-negative organisms are found more commonly when cholesteatoma is the inciting factor.

• Potential viral causes
• • 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
• • S pneumoniae
  • Haemophilus influenzae
  • Moraxella catarrhalis
  • N meningitidis
  • Streptococcus species
  • Staphylococcus species
  • Proteus species
  • Bacteroides species
  • Escherichia coli
  • Mycobacterium tuberculosis

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Other Problems to be Considered

Vertebrobasilar insufficiency
Presyncope dizziness
Cerebellar infarct
Dysequilibrium of aging
Drug-induced vertigo, hearing loss, or both

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Lab Studies

• No specific laboratory studies are available for labyrinthitis.
• Routine serology testing often fails to reveal an infectious organism, and, when results are positive, methods to determine if the same organism caused the damage to the membranous labyrinth are not available. Obtain appropriate tests to help exclude other possible etiologies in the differential diagnosis. 
• Examine cerebrospinal fluid if meningitis is suggested.
• If a systemic infection is considered, a CBC count and blood cultures are indicated.
• Perform culture and sensitivity testing of middle ear effusions if present, and select appropriate antibiotic therapy accordingly.

Imaging Studies

• CT scan 
• • Consider a 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 
• • MRI can be used to help rule out acoustic neuroma, stroke, brain abscess, or epidural hematoma as potential causes of vertigo and hearing loss. 
  • The cochlea, vestibule, and semicircular canals enhance on T1-weighted postcontrast images in persons with acute and subacute labyrinthitis.⁵ This finding is highly specific and correlates with objective and subjective patient assessment. Recent improvements in MRI techniques may make this the study of choice for suspected labyrinthitis.

Other Tests

• Audiography
• • Obtain an audiogram in all patients who may have labyrinthitis. Evaluate critically ill and severely vertiginous patients when stable and able to tolerate the test. The audiogram may show different findings depending on the etiology of the labyrinthine inflammation.
  • Persons with viral labyrinthitis have mild-to-moderate high-frequency SNHL in the affected ear, although any frequency spectrum may be affected.
  • Suppurative (bacterial) labyrinthitis typically results in severe-to-profound unilateral hearing loss. In cases of meningitis, the loss is often bilateral.
  • Persons with serous (bacterial) labyrinthitis have unilateral high-frequency hearing loss in the affected ear. A conductive loss in the same ear may occur secondary to effusion.
• Vestibular testing
• • Caloric testing and an electronystagmogram may help in diagnosing difficult cases and in establishing a prognosis for recovery.
  • Persons with viral labyrinthitis have nystagmus with unilateral caloric vestibular paresis/hypofunction.
  • Persons with suppurative (bacterial) labyrinthitis have nystagmus and an absent caloric response on the affected side.
  • Persons with serous (bacterial) labyrinthitis usually have normal electronystagmogram results, but they may have a decreased caloric response in the affected ear. However, the presence of a middle ear effusion can attenuate the caloric response and cause a false-positive finding.

TREATMENT

Section 6 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Emergency Department Care

• The initial treatment of 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 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.
• Steroids (methylprednisolone) were found to be more effective than antiviral agents (valacyclovir) for recovery of peripheral vestibular function in patients with vestibular neuritis in a randomized controlled trial by Strupp et al.⁶ This may also apply to the treatment of viral labyrinthitis.
• 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. 
• For bacterial labyrinthitis, antibiotic treatment is selected based on culture and sensitivity results. Antibiotic treatment should consist of a broad-spectrum antibiotic or combination therapy with CNS penetration until culture results are available. Treat the vertigo symptomatically as indicated. The use of steroids in meningogenic hearing loss is controversial. 
• Recent studies have shown that antioxidant therapy⁷ and cochlear microperfusion⁸ may be useful adjuvant treatments in the future.

Consultations

• Consult a neurosurgeon in the event of suppurative intracranial complications.
• Consultation with an infectious disease specialist may be warranted in the presence of systemic infection or unusual or atypical infections.

MEDICATION

Section 7 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Medication used in the treatment of labyrinthitis is primarily for relief of symptoms. Several medications have antivertiginous properties (eg, meclizine, scopolamine, ephedrine, dimenhydrinate, diazepam) and others are useful as antiemetics (eg, promethazine, prochlorperazine). Most acute episodes of labyrinthitis are short-lived and self-limited.

Drug Category: Antihistamines

These agents prevent the histamine response in sensory nerve endings and blood vessels. They are effective in treating vertigo.

Drug Category: Anticholinergic

These agents are thought to work centrally by suppressing conduction in the vestibular cerebellar pathways.

Drug Category: Benzodiazepines

By binding to specific receptor sites, these agents appear to potentiate effects of GABA and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters. These effects may prevent vertigo and emesis.

Drug Category: Phenothiazines

These agents are effective in treating emesis, possibly because of their effects in the dopaminergic mesolimbic system.

Drug Category: Monoaminergics

These agents may relieve vertigo, possibly through modulating the sympathetic system.

FOLLOW-UP

Section 8 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Further Inpatient Care

• Most patients with labyrinthitis can be evaluated and treated in the ED and then discharged.
• Some patients with intractable vertigo and vomiting may require admission.
• For those with a possible condition such as vertebrobasilar ischemia or a brainstem tumor, admission to the hospital may be appropriate under the direction of a neurologist, a neurosurgeon, or both.

Further Outpatient Care

• In cases of labyrinthitis resulting from otitis media, perform a myringotomy and evacuate the effusion. A ventilation tube also may be indicated.
• Mastoiditis and cholesteatoma are handled best with surgical drainage and debridement by way of a mastoidectomy.
• Patients with persistent vestibular symptoms may be candidates for vestibular rehabilitation. For many patients with chronic vertigo due to a peripheral vestibular etiology, a simple home program of vestibular habituation head movement exercises reduced symptoms of imbalance during stance and gait, according to Cohen and Kimball.⁹ 
• A follow-up audiogram should be performed in all patients with hearing loss and in patients who were not tested at presentation. An auditory brainstem response test is indicated for younger children.

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 hearing loss associated with viral labyrinthitis may recover somewhat. Dysequilibrium and/or positional vertigo also may be present long-term following resolution of the acute infection.
• Permanent hearing loss occurs in 10-20% of children with meningitis.
• Permanent SNHL occurs in approximately 6% of patients with herpes zoster oticus.¹⁰

Patient Education

• For excellent patient education resources, visit eMedicine's Ear, Nose, and Throat Center. Also, see eMedicine's patient education articles Labyrinthitis and Vertigo.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Medical/Legal Pitfalls

• Failure to diagnose a potentially life-threatening condition, such as meningitis, cerebrovascular ischemia, or brainstem tumor
• Failure to counsel patients regarding the potential for injury to themselves or others if they operate heavy machinery or drive a vehicle while vertiginous or while taking certain medications to control symptoms

Special Concerns

• 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.
• Avoid scopolamine (or use with extreme caution) in elderly patients.

ACKNOWLEDGMENTS

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Nicholas Y Lorenzo, MD, to the development and writing of this article.

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

1. Schuknecht HF, Kitamura K. Second Louis H. Clerf Lecture. Vestibular neuritis. Ann Otol Rhinol Laryngol Suppl. Jan-Feb 1981;90(1 Pt 2):1-19. [Medline].
2. Nadol JB Jr. Hearing loss as a sequela of meningitis. Laryngoscope. May 1978;88(5):739-55. [Medline].
3. Berlow SJ, Caldarelli DD, Matz GJ, Meyer DH, Harsch GG. Bacterial meningitis and sensorineural hearing loss: a prospective investigation. Laryngoscope. Sep 1980;90(9):1445-52. [Medline].
4. Jang CH, Park SY, Wang PC. A case of tympanogenic labyrinthitis complicated by acute otitis media. Yonsei Med J. Feb 28 2005;46(1):161-5. [Medline].
5. Mark AS, Seltzer S, Nelson-Drake J, Chapman JC, Fitzgerald DC, Gulya AJ. Labyrinthine enhancement on gadolinium-enhanced magnetic resonance imaging in sudden deafness and vertigo: correlation with audiologic and electronystagmographic studies. Ann Otol Rhinol Laryngol. Jun 1992;101(6):459-64. [Medline].
6. Strupp M, Zingler VC, Arbusow V, Niklas D, Maag KP, Dieterich M, et al. Methylprednisolone, valacyclovir, or the combination for vestibular neuritis. N Engl J Med. Jul 22 2004;351(4):354-61. [Medline].
7. Klein M, Koedel U, Pfister HW, Kastenbauer S. Meningitis-associated hearing loss: protection by adjunctive antioxidant therapy. Ann Neurol. Oct 2003;54(4):451-8. [Medline].
8. Barkdull GC, Vu C, Keithley EM, Harris JP. Cochlear microperfusion: experimental evaluation of a potential new therapy for severe hearing loss caused by inflammation. Otol Neurotol. Jan 2005;26(1):19-26. [Medline].
9. Cohen HS, Kimball KT. Decreased ataxia and improved balance after vestibular rehabilitation. Otolaryngol Head Neck Surg. Apr 2004;130(4):418-25. [Medline].
10. Gulya AJ. Infections of the labyrinth. In: Bailey BJ, Johnson JT, Pillsbury HC, Tardy ME, Kohut RI. Head and Neck Surgery-Otolaryngology. 2^nd ed. Philadelphia, Pa: JB Lippincott; 1993:1769-81.
11. Woolley AL, Kirk KA, Neumann AM Jr, McWilliams SM, Murray J, Freind D, et al. Risk factors for hearing loss from meningitis in children: the Children's Hospital experience. Arch Otolaryngol Head Neck Surg. May 1999;125(5):509-14. [Medline].

Article Last Updated: Mar 27, 2008