Labyrinthitis is an inflammation of the inner ear. It derives its name from the labyrinths that house the vestibular system (which sense changes in head position). Labyrinthitis can cause balance disorders.
In addition to balance control problems, a labyrinthitis patient may encounter hearing loss and tinnitus. Labyrinthitis is usually caused by a virus, but it can also arise from bacterial infection, head injury, extreme stress, an allergy or as a reaction to a particular medication. Both bacterial and viral labyrinthitis can cause permanent hearing loss, although this is rare.
Labyrinthitis often follows an upper respiratory tract infection(URI).
A prominent and debilitating symptom of labyrinthitis is acute vertigo. The vestibular system is a set of sensory inputs consisting of three semicircular canals, sensing changes in rotational motion, and the otoliths, sensing changes in linear motion. The brain combines visual cues with sensory input from the vestibular system to determine adjustments required to retain balance. When working properly, the vestibular system also relays information on head movement to the eye muscle, forming the vestibulo-ocular reflex, in order to retain continuous visual focus during motion. When the vestibular system is affected by labyrinthitis, rapid, undesired eye motion (nystagmus), often results from the improper indication of rotational motion. Nausea, anxiety, and a general ill feeling are common due to the distorted balance signals that the brain receives from the inner ear.
This can also be brought on by pressure changes such as those experienced while flyingor scuba diving.
Recovery from acute labyrinthine inflammation generally takes from one to six weeks; however, it is not uncommon for residual symptoms (dysequilibrium and/or dizziness) to last for many months or even years if permanent damage occurs.
Recovery from a permanently damaged inner ear typically follows three phases:
- An acute period, which may include severe vertigo and vomiting
- approximately two weeks of sub-acute symptoms and rapid recovery
- finally a period of chronic compensation which may last for months or years.
Labyrinthitis and anxiety
Chronic anxiety is a common side effect of labyrinthitis which can produce tremors, heart palpitations, panic attacks, derealizationand depression. Often a panic attack is one of the first symptoms to occur as labyrinthitis begins. While dizziness can occur from extreme anxiety, labyrinthitis itself can precipitate a panic disorder. Three models have been proposed to explain the relationship between vestibular dysfunction and panic disorder:
- Psychosomatic model: vestibular dysfunction which occurs as a result of anxiety.
- Somatopsychic model: panic disorder triggered by misinterpreted internal stimuli (e.g., stimuli from vestibular dysfunction), that are interpreted as signifying imminent physical danger. Heightened sensitivity to vestibular sensations leads to increased anxiety and, through conditioning, drives the development of panic disorder.
- Network alarm theory: panic which involves noradrenergic, serotonergic, and other connected neuronal systems. According to this theory, panic can be triggered by stimuli that set off a false alarm via afferents to the locus ceruleus, which then triggers the neuronal network. This network is thought to mediate anxiety and includes limbic, midbrain and prefrontal areas. Vestibular dysfunction in the setting of increased locus ceruleus sensitivity may be a potential trigger.
Vestibular rehabilitation therapy (VRT) is a highly effective way to substantially reduce or eliminate residual dizziness from labyrinthitis. VRT works by causing the brain to use already existing neural mechanisms for adaptation, plasticity, and compensation. The direction, duration, frequency, and magnitude of the directed exercises are closely correlated with adaptation and recovery. Symmetry is more rapidly restored when VRT exercises are specifically tailored for the patient.
Prochlorperazine is commonly prescribed to help alleviate the symptoms of vertigo and nausea.
Because anxiety interferes with the balance compensation process, it is important to treat an anxiety disorder and/or depression as soon as possible to allow the brain to compensate for any vestibular damage. Acute anxiety can be treated in the short term with benzodiazepinessuch as diazepam(Valium); however, long-term use is not recommended because of the addictive nature of benzodiazepines and the interference they may cause with vestibular compensation and adaptive plasticity. Benzodiazepines and any other form of mind or mood altering addictive drug should not be used on patients with addictive history.