Disorders of Vestibular Function: Causes

Pathogenesis (development of disease)

The vestibular organ is a part of the inner ear. Its function is to control balance (vestibular organ). If there are problems with vestibular organ, dizziness may occur. The vestibular organ consists of three semicircular canals and the two structures called macular organs (saccule and utriculus). The arcades, filled with endolymph, form the rotational sense organ. The macula organs sense the translational acceleration of the body in space. The sensory information thus obtained is transmitted via the VIII. Cranial Nerve (Nervus vestibulocochlearis) to the corresponding nerve nuclei in the brainstem (vestibular nuclei). In bilateral vestibulopathy (BV), there is bilateral inferior function or failure of the vestibular nerve and/or vestibular organ. Acute unilateral vestibulopathy may be due to reactivation of latent herpes simplex virus (HSV)-1 infection. In benign peripheral paroxysmal positional vertigo (BPPV), Meniere’s disease, and vestibular paroxysmia, there is unilateral paroxysmal pathologic excitation or, less commonly, inhibition of the vestibular nerve and/or vestibular organs. In vestibular paroxysmia, a vascular-nerve-vestibular contact is assumed to be the cause, which, however, is also found by imaging in up to 45% of all healthy individuals?! Disturbances of vestibular function due to age-related changes:

  • Organ of balance: sensory epithelium and otoliths age.
  • Vestibular nuclei: decrease in neuron number by about 3% per decade from 40 to 50 years of age.
  • Cardiovascular system: this limits the cardiac compensatory capacity.

Etiology (causes)

Peripheral-vestibular causes (disturbance of the labyrinth or/and retrolabyrinthine area).

  • Bilateral vestibulopathy (BV), eg.
    • Cogan syndrome
    • Bilateral Meniere’s disease
    • Familial vestilopathy
    • Meningitis (meningitis)
    • Congenital (angorigenic) malformations
  • Acute or subacute unilateral vestibular dysfunction (affecting the labyrinth and/or vestibular nerve).
  • Inadequate paroxysmal stimulus phenomena of the peripheral vestibular system, such as the labyrinth:
    • Benign paroxysmal positional vertigo (BPLS).
    • Vestibular paroxysmia of the vestibular nerve.

Central vestibular form of vertigo (lesions along vestibular connections from the vestibular nuclei in the medulla oblongata to the oculomotor nuclei and integration centers in the rostral midbrain and to the vestibulocerebellum, thalamus, and vestibular cortex in the temporoparietal cerebrum (Brandt et al., 2004)).

Non-vestibular organic causes

  • Chronic hypoxia (lack of oxygen supply to the tissues).
  • Dumping syndrome (tumbling of liquid and solid food from the stomach into the small intestine)
  • Electrolyte disturbances, dehydration (fluid deficiency).
  • Hematopoietic diseases (blood diseases).
  • Intoxications (alcohol, drugs and other noxious substances).
  • Cardiovascular causes (cardiovascular disease).
    • Bradycardic (heartbeat less than 60 beats per minute) and tachycardic (heartbeat greater than 100 beats per minute) arrhythmias
    • Hypotonic (“associated with low blood pressure”) regulatory disorders.
    • Current pathway obstructions
      • Basilar migraine
      • Vertebrobasilar insufficiency
      • Subclavian steal syndrome
    • Structural heart disease with decreased cardiac output (HMV).
  • Ophthalmologic (“eye-related”) causes.
  • Pharmacogenic causes (see under “Dizziness due to medication”).
  • Polyneuropathy
  • Metabolic diseases
  • Trauma-induced vertigo (traumatic brain injury (TBI); cervical spine distortions).

Ménière’s disease

Pathogenesis (disease development)

The exact trigger of Meniere’s disease is unknown. It is thought to be due to a disturbance of inner ear homeostasis of multifactorial genesis: What is certain is that the formation of an endolymphatic hydrops (endolymph hydrops; increased occurrence of water or serous fluid) occurs due to a reabsorption disorder of the endolymph (rich in potassium) in the inner ear. This mixes with the perilymph (lymph-like fluid between membranous and bony labyrinth of the inner ear; which is low in potassium) and damages nerve fibers of the auditory nerve.

Etiology (causes)

Biographic causes

  • Vegetatively unstable individuals

Behavioral causes

  • Consumption of stimulants
    • Alcohol abuse (alcohol dependence)
    • Nicotine abuse (nicotine dependence)
  • Mental stress situation

Causes related to illness

  • Allergies, unspecified
  • Viral reactivation, unspecified

Benign paroxysmal positional vertigo (BPLS)

Synonym: benign peripheral paroxysmal positional vertigo (BPPV).

Pathogenesis (disease development)

The cause of benign paroxysmal vertigo is canalolithiasis or cupulolithiasis. This refers to the presence of small concretions (stones) in the posterior or horizontal arcuate canal (organ of balance) due to detachment of the same from the otolith organs of the inner ear. Possible causes are aging processes. In 95% of cases, the etiology remains unclear.

Etiology (Causes)

Behavioral causes

  • Turning the head can trigger a seizure; especially in the morning

Disease-related causes

Ears – mastoid process (H60-H95).

  • Meniere’s disease

Psyche – nervous system (F00-F99; G00-G99)

  • Migraine, vestibular

Injuries, poisonings, and other sequelae of external causes (S00-T98).

Further

  • Condition following acute unilateral vestibulopathy (“postinfectious BPLS”).
  • Prolonged bedriddenness

Neuropathia vestibularis

Pathogenesis (disease development)

In vestibular neuritis, an inflammatory process causes the vestibular nerve to fail acutely. This may be complete or incomplete. The etiology (causes) is unknown.

Bilateral vestibulopathy

Pathogenesis (origin of disease)

Vestibular disease characterized by complete failure or incomplete deficit of both labyrinths and/or vestibular nerves. In approximately 50% of cases, the cause is unknown (idiopathic).

Etiology (causes) of the secondary form of bilateral vestibulopathy

Disease-related causes

Ears – Wart Process (H60-H95).

  • Meniere’s disease

Psyche – nervous system (F00-F99; G00-G99)

Medication

Vestibular paroxysmia

Pathogenesis (disease development)

Causally, there is compression of the VIII. Cranial nerve in the area of the brain stem is present.

Etiology (Causes)

Disease-related causes

Psyche – Nervous System (F00-F99; G00-G99).

  • Compression of the VIII. Cranial nerve in the region of the brain stem.

Medications (pharmacogenic causes of vertigo)

See also under “Anticholinergic effects due to drugs” if applicable.

Environmental exposures – intoxications (poisonings)

  • Drug use
  • Carbon monoxide
  • Carbon tetrachloride
  • Mercury