Infections of the Labyrinth | Labyrinthitis | PPT

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Infections of the Labyrinth | Labyrinthitis | PPT

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Infections of the Labyrinth

Infections of the Labyrinth

Labyrinthitis:  inflammation of the inner ear

Multiple etiologies: infectious, autoimmune, systemic disease, trauma


Infectious agents include bacteria, viruses, fungus and protozoa.



Vestibular manifestations (vertigo)


Cochlear manifestations (hearing loss)




Infection usually occurs by one of three routes:

From the meninges

From the middle ear space

Hematogenous spread


Meningogenic: through the IAC, cochlear aqueduct, both (bilateral)

Tympanogenic: extension of infection from the middle ear, mastoid cells or petrous apex-most common through the round or oval window (unilateral)

Hematogenous:  least common

Bacterial Infections

Two types of labyrinthitis associated with bacterial infections:


Toxic Labyrinthitis

Suppurative Labyrinthitis

Bacterial Infections

Toxic Labyrinthitis: results from a sterile inflammation of the inner ear following an acute or chronic otitis media or early bacteria meningitis.

Toxins penetrate the round window, IAC, or cochlear aqueduct and cause an inflammatory reaction in the perilymph space.


Bacterial Infection

Toxic Labyrinthitis produces mild high frequency hearing loss or mild vestibular dysfunction

Treatment: Antibiotics for precipitating otitis, possible myringotomy.

Bacterial Infection

Suppurative Labyrinthitis: direct invasion of the inner ear by bacteria.

From otitis or meningitis


Bacterial Infection

Suppurative Labyrinthitis: 4 stages

Serous or irritative: production of Ig rich exudates in the perilymph

Acute or purulent: bacterial and leukocyte invasion of the perilymphatic scala-end organ necrosis

Fibrous or latent: proliferation of fibroblasts and granulation tissue in the perilymph

Osseous or sclerotic: new bone deposition throughout the involved labyrinth

Bacterial Infection

Purulent Labyrinthitis:  medical emergency

Meningitis or Otitis symptoms

Hospitalization, hydration, vestibular suppressants and iv antibiotics

Bacterial Meningitis

H. influenza B, N. meningitidis, S. pneumoniae


Hib vaccine: 55% decrease in cases


Pneumococcus now predominant org.

Bacterial Meningitis

Postmeningitis hearing loss 10-20%

Bilateral, severe to profound, permanent


Treponema pallidum

Diagnosis by FTA-ABS and confirmed by Western Blot.

Congenital or Acquired


Acquired: SNHL during secondary or tertiary


Early: high fetal and infant mortality

Late SNHL+/- vestibular symptoms


Viral Infections

Congenital Infection

Systemic viral illness

Isolated involvement of inner ear




Most common congenital infection in US

Most common infectious cause of congenital deafness

Low birth weight, jaundice, hepatosplenomegaly, petechiae, microcephaly and psychomotor retardation.

65% w SNHL-bilateral, severe to profound


Diagnosis by isolating virus from urine during first few weeks of life.

Virus isolation form cord blood


No treatment: acyclovir may decrease amount of shedding, gancyclovir & foscarnet not approved during pregnancy.


1969 58/100000

1983 0.5/100000

Decline due to vaccine

Congenital rubella: cataracts, heart malformations and SNHL, others

Dx by viral culture

No treatment; prevention only



Parotitis, orchitis, meningoencephalitis, and in 0.05% of cases-hearing loss.

Hearing loss at end of first week of parotitis, unilateral and range from mild, high frequency SNHL to profound SNHL.

Vestibular involvement is uncommon


Rubeola virus

Systemic illness w rash, conjunctivitis, and mucosal Koplik spots.

Measles induced hearing loss is 1/1000 cases

Measles less common 2nd to vaccine



Encephalitis in 0.1% of cases w overall mortality rate of 15%, with 25% of survivors with SNHL.

SNHL seen in conjunction with rash.

Sudden onset

Varies from mild to profound HF SNHL

Unilateral or bilateral


70% have vestibular losses also



Primary vzv=chicken pox

HL w chicken pox = CHL 2nd to MEE


Herpes zoster oticus= Ramsay Hunt syndrome, reactivation from the geniculate ganglion of CN VII.  Painful vesicles.

1/3 have auditory or vestibular symptoms-HFHL, hyperacusis, tinnitus, vertigo

Herpes simplex

Labyrinthine infection by:

Reactivation in the spiral ganglion=SSNHL

Extension of the meningoencephalitis along CN VIII to the labyrinth=acquired SNHL


HSV-1 &2 can infect labyrinth.  Animal models of ISSNHL.  ??Humans.

Neuroepithelial cells of the cochlea, utricle, saccule, and semicircular canals infected with HSV

Circumstantial evidence only

Human Immunodeficiency virus

Auditory and vestibular complaints rare in AIDS patients

Some w hearing loss, tinnitus and vertigo

Thought to be result of opportunistic infections (CMV, HSV), ototoxic drugs, neoplasm of inner ear.

Fungal Infections

Fungal labyrinthitis is exceedingly rare outside the context of host immunocompromise.

High risk: diabetics, chemo therapy, organ transplant recipients, AIDS patients

Agents include Mucor, Cryptococcus, Candida, Aspergillus, and Blastomyces

Hearing loss is severe and permanent


Toxoplama gondii most common

Acquired infection usually asymptomatic

Congenital infection may lead to severe malformations of fetus

Triad of chorioretinitis, hydrocephalus, intracranial calcifications

May also have microcephaly, cataracts, micropthalmia, jaundice, and hsm.

3000 cases annually



75% asymptomatic at birth

15% ocular problems

10% severe malformations

85% of symptomatic infants at birth will later develop decreasing visual acuity, decreased intellectual function, hearing loss or precocious puberty.


Screening test to determine fetal infection

PCR analysis of amniotic fluid

IgM assays

Quantitative maternal/fetal IgG analysis of cord blood




Prenatal tx reduces both transmission and severity of illness in the fetus

Combination of pyrimethamine and sulfonamide

Neonates with documented infection should be given tx for 1st year of life + folic acid supplements

Clinical Presentation

Pts present with only auditory dysfunction-acute cochlear labyrinthitis

Pts present with only vestibular dysfunction-acute vestibular labyrinthitis

Both-acute cochleovestibular labyrinthitis

Clinical presentation

Acute cochlear labyrinthitis, aka idiopathic sudden sensory neural hearing loss (ISSNHL)

Defined as minimum of 30dB deficit in three contiguous frequencies over a period of less than 3 days in a previously healthy person.

3 pathologic theories: viral infection, vascular phenomenon, intralabyrinthine membrane rupture.

Much circumstantial evidence of viral etiology

Acute cochlear labyrinthitis

Treatment is steroids.  Studies have shown no benefit of steroids and antivirals.

30-70% have complete recovery of hearing.

Prognosis related to age, time from onset to presentation, type of audiogram, presence of vestibular symptoms

<40 years

Seen within 10 days

Started on steroids within 10 days

Clinical presentation

Acute vestibular labyrinthitis, aka vestibular neuritis

Defined as sudden unilateral vestibular weakness in the absence of concomitant auditory or CNS dysfunction in a previously healthy person

Acute vestibular labyrinthitis

Diagnostic criteria:

An acute, unilateral, peripheral vestibular disorder w/o associated hearing loss

Occurrence predominantly in middle age

A single episode of severe, prolonged vertigo

Decreased caloric response in the involved ear.

Complete subsidence of the symptoms within 6 months

Acute vestibular labyrinthitis

Treatment is supportive and includes hydration, antiemetics, and vestibular suppressants.



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