Balance

There are four main components of the vestibular system that must function properly in order for an animal to maintain balance. Disruption in communication along their pathways could result in vestibular disease:

  1. The sensors in the inner ear monitor head position in space and time (i.e. acceleration, deceleration, rotation, etc).
  2. The information about the position of the head is converted into electrical signals in the inner ear and sent via the vestibulocochlear nerve to the lower portion of the brain.
  3. The balance control centers in the brainstem work together with the cerebellum to process this information. They send messages to the rest of the body that keep an individual upright.
  4. The vestibular nuclei relay signals from the brainstem to the cerebellum which uses constant feedback on body position to coordinate movement.

Disorders of the vestibular system are organized into peripheral (inner ear and nerve) or central (brain and cerebellum) vestibular disease.


COMMON SIGNS:

  • lack of balance
  • head tilt
  • circling
  • nausea
  • falling/rolling
  • nystagmus
  • tremors
  • ataxia
  • Horner's syndrome
  • hypermetria

COMMON CAUSES: Peripheral Vestibular Diseases (Inner Ear & Vestibulocochlear Nerve)

    • Inflammatory
      • infectious
        • otitis media/interna
        • tetanus
      • immune-mediated
        • polyps
    • Neoplastic (inner / middle ear)
      • melanoma
      • squamous cell carcinoma
      • adenocarcinoma
    • Traumatic
      • head injury
      • eardrum rupture
    • Toxic
      • medications
    • Idiopathic
      • geriatric vestibular syndrome

COMMON CAUSES: Central Vestibular Diseases (Brainstem & Cerebellum)

    • Degenerative/Metabolic
      • cerebellar abiotrophy
        • breed specific (Kerry Blue, Gordon Setter)
    • Congenital
      • cerebellar hypoplasia
      • hydrocephalus
    • Inflammatory
      • Immune-Mediated
        • cerebellitis / white dog shaker syndrome
    • Neoplastic
      • medulloblastoma
    • Traumatic
      • head injury
    • Toxic
      • metronidazole
    • Vascular