What you see. The starting point for addressing any equine health related issue is your observation.


Local Muscle Twitching


Muscle trembling (fasciculation) that occurs in a specific area (not all over) can range from obvious shaking to subtle twitching. Commonly affected areas include the face, especially the muzzle and eyelid, the trunk, upper limb, back or neck.

Localized muscle twitching is often seen with electrolyte imbalance, local nerve injuries, certain neurologic and muscular diseases, and a variety of other conditions. Years ago, during a large outbreak of West Nile Virus, I noticed that almost every affected horse had fine muscle tremors, usually of the muzzle, lips, and face.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the results of the Whole Horse Exam (WHE) indicate fever (Temp>101F/38.3C), or heart rate greater than 48 BPM that persists an hour after recovery from exercise.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the horse's appetite and attitude are normal and you see nothing else wrong.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
You also might be observing
Very Common
Less Common
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your role


What To Do

If you notice an area of the horse that seems to be twitching or trembling, take some time to look carefully at the specific areas affected. Is the trembling body-wide or local? Assess your horse's general health using the Whole Horse Exam (WHE), and look for other signs of illness or disease. Take special note of rectal temperature, heart rate, attitude and appetite. Share your findings and concerns with your vet.

your vet's role

If there are no other signs of injury or illness, your vet may advise you to give the horse electrolytes or monitor the horse for awhile.
Questions Your Vet Might Ask:
  • Does the horse's appetite and attitude seem normal?
  • What is the horse's age, sex, breed and history?
  • Is the horse vaccinated for Rabies, Encephalitis and West Nile virus?
  • Has the horse been exercised recently?
  • Is the horse an American Quarter Horse with Impressive bloodlines?
  • Do you know of any recent stresses or changes in management?
  • Has the horse been tested for HYPP?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
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Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
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Author: Doug Thal DVM Dipl. ABVP