Infections of the Labyrinth

1. 1 Infections of the Labyrinth Sam J. Cunningham, MD, PhD Arun Gadre, MD UTMB Dept of Otolaryngology February 2004

2. 2 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.

3. 3 Labyrinthitis Vestibular manifestations (vertigo) Cochlear manifestations (hearing loss) Both

4. 4 Labrynthitis Infection usually occurs by one of three routes: From the meninges From the middle ear space Hematogenous spread

5. 5 Labyrinthitis 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

6. 6 Bacterial Infections Two types of labyrinthitis associated with bacterial infections: Toxic Labyrinthitis Suppurative Labyrinthitis

7. 7 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.

8. 8 Bacterial Infection Toxic Labyrinthitis produces mild high frequency hearing loss or mild vestibular dysfunction Treatment: Antibiotics for precipitating otitis, possible myringotomy.

9. 9 Bacterial Infection Suppurative Labyrinthitis: direct invasion of the inner ear by bacteria. From otitis or meningitis

10. 10 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

11. 11 Bacterial Infection Purulent Labyrinthitis: medical emergency Meningitis or Otitis symptoms Hospitalization, hydration, vestibular suppressants and iv antibiotics

12. 12 Bacterial Meningitis H. influenza B, N. meningitidis, S. pneumoniae Hib vaccine: 55% decrease in cases Pneumococcus now predominant org.

13. 13 Bacterial Meningitis Postmeningitis hearing loss 10-20% Bilateral, severe to profound, permanent

14. 14 Syphilis Treponema pallidum Diagnosis by FTA-ABS and confirmed by Western Blot. Congenital or Acquired

15. 15 Syphilis Acquired: SNHL during secondary or tertiary Congenital: Early: high fetal and infant mortality Late SNHL+/- vestibular symptoms

16. 16 Viral Infections Congenital Infection Systemic viral illness Isolated involvement of inner ear

17. 17 Cytomegalovirus 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

18. 18 CMV 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.

19. 19 Rubella 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

20. 20 Mumps Paramyxovirus 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

21. 21 Measles 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

22. 22 Measles 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 PERMANENT 70% have vestibular losses also

23. 23 Varicella-zoster Primary vzv=chicken pox HL w chicken pox = CHL 2nd to MEE Reactivation=zoster 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

24. 24 Herpes simplex Labyrinthine infection by: Reactivation in the spiral ganglion=SSNHL Extension of the meningoencephalitis along CN VIII to the labyrinth=acquired SNHL

25. 25 HSV 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

26. 26 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.

27. 27 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

28. 28 Protozoa 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

29. 29 Toxoplasma 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.

30. 30 Toxoplasma Screening test to determine fetal infection PCR analysis of amniotic fluid IgM assays Quantitative maternal/fetal IgG analysis of cord blood

31. 31 Toxoplasma Treatment 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

32. 32 Clinical Presentation Pts present with only auditory dysfunction-acute cochlear labyrinthitis Pts present with only vestibular dysfunction-acute vestibular labyrinthitis Both-acute cochleovestibular labyrinthitis

33. 33 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

34. 34 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

35. 35 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

36. 36 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

37. 37 Acute vestibular labyrinthitis Treatment is supportive and includes hydration, antiemetics, and vestibular suppressants.

38. 38 References Gulya, AJ Infections of the Labyrinth. Head and Neck Surgery-Otolarygology, BJ Bailey ed. Philadelphia. 2001. Rosen, EJ Infections of the Labyrinth. UTMB Dept of Otolaryngology Web site in �Dr. Quinns Online Textbook and Grand Round Archives. 2000. Stokroos, RJ Antiviral treatment of idiopathic sudden sensorineural hearing loss: a prospective, randomized, double-blinded clinical trial. Acta Oto-Laryngologica. 118(4):488-95, Jul 1998. Stokroos, RJ The etiology of idiopathic sudden sensorineural hearing loss. Experimental herpes simplex virus infection of the inner ear. Am J of Otology. 19(4): 447-52, Jul 1998. Paparella, MM. Labyrinthitis. Pp 81-92. June 12, 1978. Satoh, H. Proinflammatory cytokine expression in the endolymphatic sac during ear inflammation. Jaro. 4(2): 139-47, Jun 2003. Westerlaken, BO. Treatment of idiopathic sudden sensorineural hearing loss with antiviral therapy: a prospective, randomized, double blind clinical trial. Ann Oto, Rhino, Laryn. 112(11):993-1000. Nove 2003. Arbusow V. HSV-1 not only in human vestibular ganglia but also in the vestibular labyrinth. Audiology and Neuro-Otology. 6(%):259-62, Sept. 2001. Furman, J. Vestibular Disorders. 2nd ed. New York. Oxford Pub. 2003.