Neurological Examination Initial Observation - Horse

Signalment and History

Signalment

• The term "signalment" describes the animal's age, sex and breed.
• The horse's signalment may be relevant to the neurological examination.
  • For example:
    • A 1 year old thoroughbred colt with ataxia is more likely to have cervical compression than a space occupying lesion.
    • An Arabian foal suffering seizures may have idiopathic epilepsy.

History

• History is a very important component of the neurological examination.
  • An owner's description of the animal's behaviour or abnormality may both
    • Help direct the neurological examonation.
    • Suggest possible differential diagnoses.
• For example, a recumbent horse with a history of stumbling or knuckling that has recently fallen:
  • May have underlying cervical vertebral malformation or stenosis, OR
  • It is possible that the onset of pelvic limb weakness may have followed a spate of respiratory disease or an abortions, if the animal has EHV1 myelitis.

Demeanour/ Behaviour

• The horse should be examined from a distance to assess behaviour and demeanour.
• Diseases associated with altered mentation or behaviour tend to involve the forebrain.
• Levels of consciousness are determined partly by the cerebrum and partly by the reticular activating system in the brainstem.

What to Look For

• Assymetrical changes.
  • These include:
    • Circling
    • Head turning
  • Horses usually circle or turn towards the affected side.
• Excessive yawning.
• Head pressing.
  • This is often a sign of severe obtundation, which may be caused by:
    • Diffuse cerebral disease.
    • Metabolic problems, such as hepatic encephalopathy.