What is the difference between ataxia and paresis?
Ataxia: incoordination of the gait. There are three types of ataxia:
Proprioceptive ataxia: loss of proprioceptive signals from the limbs. Doing paw replacement test does not help differentiate cerebral or spinal cord lesions.
Vestibular ataxia: asymmetric ataxia, falling, drifting toward one side, turning in tight circle, +/- head tilt. Dysfunction of central (medulla) or peripheral (CN VIII) vestibular nuclei or nerve, respectively.
Cerebellar ataxia: symmetric hypermetria, loss of balance, truncal sway and ataxia, wide based stance, +/- intention tremor. This most often represents a dysfunction in the cerebellum.
Paresis: weak movement, incomplete paralysis. This involves most commonly the UMN or LMN, but remember the neuromuscular junction, muscle and bones or joints can be a source of paresis (weakness).
** Animals with paresis ONLY (no ataxia) are not likely to have a spinal cord lesion! This is one of the best reasons to become familiar with the difference between ataxia and paresis... and it's a hard thing to do! Residents train for years to identify the difference between ataxia and paresis.
Animals with a spinal cord lesion localization have things like disc herniations, FCE and spinal tumors as the cause of their clinical signs. Animals with paresis ONLY (no ataxia) have neuromuscular disease (myasthenia gravis, for example), myopathies (Cushings myopathy, for example) and orthopedic disease (cruciate ruptures quite commonly!) but do not have spinal cord disease.
Have a case with ataxia or paresis? Let me know! The website is now up and running for you to schedule video consults and telephone consults on your own (if you wish to do so). https://barnesveterinaryservices.com or you can email me directly. On site consults are scheduled on an individual basis because of the Safe at Home restrictions. Please email or call me to discuss the case if you think it would benefit from an on site consult, not video consult.
Stay safe and please stay healthy!