What kind of inner ear infections occur?

Infections of the Inner Ear

The more common causes of ear infection are either viral or bacterial.

Viral infections

Four viral infections which cause the labyrinth are thought to reach it via the bloodstream: cytomegalovirus, mumps, measles and rubella. Herpes Zoster, another viral infection, enters the inner ear via the seventh and eight nerves.

-the developing human ear is most susceptible to this infection and has been cited as one of the most common causes of congenital hearing loss.

Rubella

– bilateral SNHL (unilateral may occur) Maternal rubella was a major cause of congenital SNHL, immunization has significantly reduced its occurrence. Virus leads to a partial collapse of reissner’s membrane, with adherence to the stria vascularis and organ of corti.

Measles

- bilateral moderate to severe 40-80 dB HL flatish audiogram. Also conductive loss is quite common, i.e. mixed, due to middle ear erosion.

Mumps

- unilateral sudden severe to profound loss and can be reversible.

Herpes Zoster

- sudden cochlea and retro cochlea loss, usually associated with severe pain and vesicular rash on the external ear.

Tinnitus and vertigo can also follow later (variation of shingles). Bell’s palsy can also be a consequence of this and other viral ear infections.

Bacterial Infections

Bacterial infections of the inner ear are usually an extension of middle ear infections. Four routes are possible;

• Via mastoid air cells. • As a direct of the inflammatory process. • Through penetration of the oval or round window. • Via nerves and vessels.

Labyrinthitis

is inflammation of the membranous labyrinth, again as a result of otitis media or meningitis.

Bacterial meningitis

(as opposed to viral meningitis, which rarely causes hearing loss) finds its way into the inner ear either by the internal auditory meatus or the cochlea aqueduct.

Bilateral SNHL,

usually profound.

Syphilis

has not been fully eradicated by penicillin treatment. Sensori-neural hearing loss is common in all forms of acquired syphilis. In its later stages vertigo and tinnitus can occur.