This is also referred to as trigeminal mediated headshaking in horses or photic headshaking. In horses this can be debilitating leading to loss of use and inability to ride. A list of other diseases/conditions needs to be ruled out prior to making the diagnosis. There are no proven medications that can “cure” headshaking. Modifying the tack or light sensitivity can exacerbate the issue as well. Here is how we diagnosed and successfully treated headshaking in this patient with integrative medicine.
Prior to making the diagnosis, we performed multiple diagnostics to rule out other conditions:
- Upper airway endoscopy
- Oral exam and dental float
- Lameness exam (in hand and under saddle)
- Neurologic exam with cranial nerve function tests
- Skull and cervical radiographs
- Diagnostic nerve blocks
- Exercises with and without a bridle +/- shade vs. sunlight
After excluding many pathologies, we found that this patient’s headshaking was worsened when wearing a bridle. He could not go a few meters without tossing/shaking his head, stopping, snorting, or rubbing his nose. The last test we performed to diagnose the condition was a trigeminal nerve block. In the first picture you can see Dr. Daniel performing an ultrasound guided block of the maxillary nerve (a branch of the trigeminal nerve- Figure 1). After 10-15 minutes the patient lost nasal sensation and was able to trot with his normal bridle without tossing his head or rubbing his face.
Unfortunately, there are not many Western medical options to treat headshaking in horses. The owners opted to try acupuncture and within 7 sessions the patient was completely back to normal. Dr. Gracida performed electroacupuncture for the first two sessions and dry needling for the remaining 5 sessions (Figure 2). He is now being ridden with his normal tack, free of headshaking or nose rubbing.
Why do horses to headshake?
The trigeminal nerve is commonly “irritated” in horses that headshake. There are three branches of the trigeminal nerve and some portions lay just beneath the skin. When the bridle, or even the halter, presses over these nerves, the condition can worsen. The trigeminal nerve gives sensation to the face and is involved with motor function to muscles involved with chewing. The trigeminal nerve also has a higher density of pain fibers (C fibers) compared to other nerves making conditions that affect the trigeminal nerve much more painful even with lower stimulation.
Disruption of the trigeminal nerve function can cause odd sensations like tingling, crawling/itching, pricking, or pain to the face known as paresthesia. This is why headshaking occurs as well as facial rubbing seen in this patient.
Although medical management is often unsuccessful, acupuncture is quite helpful because it targets restoration of nerve function. The portions of the trigeminal nerve just beneath the skin can be targeted as well as other acupuncture points in the whole body. By reducing the electrical resistance and increasing electrical conduction of the nerves, the normal function can be restored.
If you would like to consult about your horse located near Jupiter, Wellington, or Parkland give us a call 561-515-2685.