Vestibular Neuritis or Labyrinthitis is an inner ear infection. The infection causes the labyrinth (which is deep in the ear) to become inflamed. This can affect both your hearing and balance.

The labyrinth is the innermost part of your ear. It contains the cochlea (which) relays sounds to the brain and is responsible for hearing; and
the vestibular system which is a complex set of fluid-filled channels that contributes to your sense of balance.

The most common symptoms are dizziness, hearing loss (from mild to complete loss ) and vertigo which is when a person feels like if they or the objects around them are moving when they are not. In extreme cases people are unable to remain upright.

Other symptoms include:-

nausea
earache and headaches
pressure inside the ear
tinnitus
fluid leaking out of the ear

a high temperature (fever) of 38C (100.4F) or above
changes in vision, such as blurred vision or double vision
mild headaches