Written by a CuraCore Veterinary Medical Acupuncture course graduate. Signed release obtained from client/author. 3D2019003
ABSTRACT:
Suspected trigeminal neuritis with generalized atrophy, dysphagia, and severe masseter atrophy post bilateral mandibular fracture and repair in a 5 year old Arabian gelding. Electroacupuncture utilized to stimulate trigeminal nerve, especially mandibular and maxillary branches. Patient began to have increased coordination in prehension the day following initial treatment and was discharged to recover at home after six sessions of electroacupuncture under sedation.
HISTORY OF PRESENT ILLNESS AND CHIEF COMPLAINT(S):
Diamond is a 5 year old Arabian gelding. Diamond presented on 4/22/19 for a bilateral mandibular fracture which occurred when he got his head stuck between a fence and a post, that was reduced using interdental wire and was discharged on 4/29/19. Possible facial nerve paralysis was noted at time of discharge. Diamond was eating well but recently began to drop feed after chewing and had lost weight.
PHYSICAL EXAMINATION AND CLINICAL ASSESSMENTS:
Upon presentation (5/12/19), gastrointestinal sounds were decreased bilaterally but other vitals were within normal limits (Temperature: unable to collect – 99.9F on 5/13/19 with sedation; Pulse: 32bpm; Respirations: 12brpm; Mucosal Membranes/Capillary Refill Time: unable to collect – pink, moist/<2 seconds on 5/13/19 morning; Digital pulses normal x4). The lower lip was drooping especially on the left and the tongue, although mobile, was extended slightly. Significant atrophy bilaterally of masseter muscle and decreased body condition score. Draining tracts present with mucopurulent discharge on chin from interdental wire insertion.
Radiographs (5/13/19) found mild ventral displacement of mandibular fractures but no other bony changes (caudal mandible, temporomandibular joint) were identified.
Internal medicine consult (5/13/19) found multiple signs (masseter muscle atrophy, dropped mandible, dropped/protrusion of tongue) consistent with trigeminal neuropathy. When given hay, Diamond could pick up the hay and could push it to the areas of his premolars and molars; however, he would exhibit weak mastication/chewing, and would drop feed from his mouth. When given applesauce, Diamond was noted to pick up the applesauce and was able to swallow.
Myofascial exam (5/14/19) did not include examination of limbs or hips due to patient temperament. Generalized topline atrophy and significant bilateral masseter atrophy was appreciated. The lower lip droops, more so on the left, but is mobile. The left point of the shoulder and proximal left craniolateral neck were warm, as was the entirety of the right neck to point of the shoulder. Walking demonstrated a mild, Grade 2, left rear limb lameness.
PROBLEM LIST:
• Historical bilateral mandibular fracture due to trauma – reduced with interdental wire
o Grade 2 left rear limb lameness
o Warmth of neck
o Mucopurulent draining tract on chin
• Dysphagia, masseter atrophy, and lip drooping
o Decreased borborygmi
• Generalized atrophy
o Grade 2 left rear limb lameness
DIFFERENTIAL DIAGNOSES:
Dysphagia, masseter atrophy, and lip drooping
• V(ascular): Hypotensive event during anesthesia for fracture repair
• I(nfectious): Equine Protozoal Myeloencephalitis
• N(eoplastic): Compressive mass effect impinging on trigeminal +/- facial nerves
• D(egenerative): Osteoarthritis impinging on trigeminal or facial nerves or of temporomandibular joint
• I(atrogenic, intoxication): Heavy metal toxicity
• C(ongential): Temporomandibular malocclusion/subluxation secondary to malformation
• A(utoimmune): Polyneuritis equi, immune mediated myopathy
• T(raumatic): Trigeminal +/- facial neuropathy associated with original injury
• E(ndocrine, metabolic): Masseter myodegeneration
• M(yofascia): Scarring of myofascial tissue entrapping trigeminal nerve
Generalized atrophy
• V(ascular): Parasitic thrombosis
• I(nfectious): Gastrointestinal parasites or dysbiosis, gingivitis
• N(eoplastic): Intestinal lymphoma
• D(egenerative): Equine Motor Neuron Disease
• I(atrogenic, intoxication): Deceased appetite due to unmanaged pain or gastric ulceration
• C(ongential): Equine Polysaccharide Storage Disorder
• A(utoimmune): Immune Mediated Myositis
• T(raumatic): Fractured mandible reducing appetite and ability to eat, Neurogenic atrophy
• E(ndocrine, metabolic): Selenium deficiency
• M(yofascia): Pain from a myofascial source (eg neck) reducing appetite
DEFINITIVE DIAGNOSES:
Due to history, physical exam, acute onset of signs, and most significant atrophy associated with masseter, I suspect the dysphagia, masseter atrophy, and lip drooping is due to a trigeminal +/- facial neuropathy secondary to original trauma or trauma during post-operative time. It is most likely the generalized atrophy is due to decreased intake secondary to fractured mandible, myofascial pain, and masseter weakness from neurogenic atrophy.
MEDICAL DECISION MAKING:
Point Reasoning Method Frequency
LI16 (bilaterally) Relaxation, peripheral stimulation Dry needle Once daily until discharge, as tolerated
Bai Hui Relaxation, autonomic neuromodulation Dry needle Once daily until discharge, as tolerated
GV20 Relaxation, autonomic neuromodulation Dry needle Once daily until discharge, as tolerated
TH17 (bilaterally) Facial/trigeminal nerve stimulation Dry needle Once daily until discharge, as tolerated
LI20 (bilaterally) Facial/trigeminal nerve stimulation Dry needle Once daily until discharge, as tolerated
ST4 (bilaterally) Trigeminal nerve (maxillary branch) stimulation Electroacupuncture Once daily under sedation until discharge, as tolerated
ST7 (bilaterally)
GB20 (bilaterally) Trigeminal nerve (mandibular branch) stimulation Electroacupuncture Once daily under sedation until discharge, as tolerated
Masseter muscle belly (bilaterally)
MEDICAL ACUPUNCTURE AND RELATED TECHNIQUES USED:
• 5/14/19 AM: GV14, Bai Hui, LI16 (bilaterally) with Seirin J #3 for 5 minutes
o Points chosen for general relaxation and to assess acceptance of needling
o ST7 (right) and GV20 were attempted but patient did not tolerate
• 5/14/19 PM while sedated: LI16 (bilaterally) and Bai Hui with Seirin J #5 for 30 minutes; Bilaterally TH17 and LI20 with Seirin J #5 for 15 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes
o Points chosen for general relaxation and stimulation of trigeminal nerve
o Electroacupuncture via Electrostimulator 8c.Pro by Pantheon Research using Mixed Mode with 2Hz and 100Hz settings
• 5/15/19 PM while sedated: LI16 (bilaterally), Bai Hui, and TH17 (bilaterally) with Seirin J #5 for 20 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes (as before)
• 5/16/19 PM while sedated: LI16 (bilaterally), Bai Hui, and TH17 (bilaterally) with Seirin J #5 for 20 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes (as before)
• 5/17/19 PM while sedated: LI16 (bilaterally), Bai Hui, and TH17 (bilaterally) with Seirin J #5 for 20 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes (as before)
• 5/18/19 AM while sedated: LI16 (bilaterally), Bai Hui, and TH17 (bilaterally) with Seirin J #5 for 20 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes (as before)
• 5/19/19 AM while sedated: LI16 (bilaterally), Bai Hui, and TH17 (bilaterally) with Seirin J #5 for 20 minutes; Electroacupuncture between ST4 and ST7 / GB20 and masseter muscle belly with Seirin J #5 for 10 minutes (as before)
OUTCOMES, INSIGHTS, DISCUSSION, AND REFERENCES:
Diamond began to demonstrate increased coordination in prehension the day following initial treatment and continued to improve during the hospital stay. Mastication was still weak due to atrophy but movements appeared more effective and deliberate. Due to improvements and hospitalization cost, Diamond was discharged after six sessions of electroacupuncture. Per owner, Diamond ate ravenously once home. We suspect Diamond will continue to recover as muscle mass is regained via use and protein intake and as trigeminal neuritis resolves, albeit more slowly without external stimulation.
Diamond was very sensitive to touch on the head, especially on the right side, and would not tolerate needle placement without sedation. Although sedation is less than ideal, it allowed for electroacupuncture to be performed to stimulate the targeted tissues. It is very likely that Diamond was in pain due to his injuries and had anxiety regarding facial contact. Diamond appeared very relaxed during treatment and this may be due to the analgesic effects of the acupuncture. Analgesia was not our primary treatment goal but was a good outcome. Additionally, it is possible Diamond experienced a type of pain sensation, especially on the right, akin to a trigeminal neuralgia. It was difficult to assess pain versus hyperalgesia versus allodynia versus anxiety in the patient. It may have been easier to assess if it was known how the patient was initially handled with fracture repair to rule out behavioral and anxiety responses.
Diamond’s case was a good example of both treating a peripheral nerve injury and of treating the trigeminal nerve in particular. The trigeminal nerve is implicated in some cases of headshaking in horses and this protocol could be used in treatment. The concepts of this protocol also would apply for other peripheral nerve injuries but could be improved with additional distal points and spinal segmental points, as indicated.
Relevant articles:
• Devereux, S. (2019). Electroacupuncture as an additional treatment for headshaking in six horses. Equine Vet Educ, 31: 137-146. doi:10.1111/eve.12776
• Rice, M. K. (2017). Regional Nerve Blocks for Equine Dentistry. Journal of Veterinary Dentistry, 34(2), 106–109. https://doi.org/10.1177/0898756417713730
• MacKay, R. J. (2011). Diseases of the Brainstem and Cranial Nerves of the Horse: Relevant Examination Techniques and Illustrative Video Segments. AAEP Proceedings, 57: 353-357.