ISSN 2398-2969      

Trigeminal neuropathies


Synonym(s): Trigeminal neuritis, Idiopathic trigeminal neuropathy, Mandibular nerve neurapraxia, Idiopathic mandibular paralysis


  • Trigeminal nerve branches: ophthalmic, maxillary, mandibular.
  • Most common trigeminal neuropathy is idiopathic mandibular paralysis.
  • Cause: inflammation, neoplasia, trauma.
  • Signs:
    • Ophthalmic branch: corneal anesthesia, loss of sensation to nasal septal mucosa, skin on dorsum of nose, upper eyelid, eye medial canthus.
    • Maxillary branch: loss of sensation to eye lateral canthus, lower eyelid, skin of the cheek, side of the nose, muzzle, palates, mucous membrane of nasopharynx, teeth and gingiva of upper jaw.
    • Mandibular branch: unilateral or bilateral paralysis of masticatory muscles → inability to close mouth, difficulty eating and drinking. Loss of sensation to mandibular portion of the face and oral cavity.
  • Diagnosis: signs, histopathology, MRI.
  • Treatment: supportive care.



  • Idiopathic.
  • Space-occupying lesions, eg neoplasia.
  • Trauma to head, especially jaw.
  • Trigeminal nerve abnormalities can occur with infiltrating neoplasia (lymphosarcoma, leukemias Leukemia ), that involve a branch or the entire nerve.
  • Other cranial nerves (VII), and the sympathetic supply to the eye may be involved concurrently.
  • Animals that have systemic hematological neoplasia that develop cranial nerve abnormalities should be evaluated for extension of the tumor to these sites.
  • Nerve sheath tumors Nerve sheath: neoplasia may arise within the trigeminal nerve:
    • Clinical signs of unilateral temporalis and masseter muscle ipsilateral to the lesion are most common.
    • The lesion is found with CT and, more often, MR imaging.
    • Surgical treatment can result in long-term resolution of the disease.
  • Trigeminal neuritis is an idiopathic inflammatory disease of the mandibular branches of V bilaterally:
    • The dog presents with a dropped jaw.
    • The etiology is unknown.
    • A non-suppurative inflammatory neuritis in the motor branches of the trigeminal nerve and its ganglion has been confirmed in some cases.
    • Most dogs should improve with time (within 2-10 weeks).
    • No treatment has shown benefit.


  • Inflammation or degeneration trigeminal nerve → loss of trigeminal nerve function → loss of sensation to face and mouth, loss of motor function to masticatory muscles → unable to close jaw → masticatory muscle atrophy.
  • A unilateral dysfunction of all three branches of V is almost always associated with a peripheral V lesion (outside the brain stem), because the nuclear areas of V are so extensive that central destruction of all of these nuclei would be incompatible with life.
    Remember, just because a lesion is peripheral it does not mean that it is not intracranial, eg a tumor involving CN V in the trigeminal canal.


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Milodowski E J, Amengual-Batle P, Beltran E et al (2019) Clinical findings and outcome of dogs with unilateral masticatory muscle atrophyJ Vet Intern Med 33, 735-742 PubMed.
  • Kent M, Glass E N, de Lahunta A et al (2013) Prevalence of effusion in the tympanic cavity in dogs with dysfunction of the trigeminal nerve: 18 cases (2004-2013).  J Vet Intern Med 27, 1153-1158 PubMed.
  • Roynard P, Behr S, Barone G et al (2012) Idiopathic hypertrophic pachymeningitis in six dogs: MRI, CSF and histological findings, treatment and outcome. J Small Anim Pract 53, 543-548 PubMed.
  • Mayhew P D, Bush W W, Glass E N (2002) Trigeminal neuropathy in dogs: a retrospective study of 29 cases (1991-2000).  J Am Anim Hosp Assoc 28, 262-270 PubMed.
  • Pfaff A M, March P A, Fishman C (2000) Acute bilateral trigeminal neuropathy associated with nervous system lymphosarcoma in a dogJ Am Anim Hosp Assoc 36, 57-61 PubMed.
  • Bagley R S, Wheeler S J, Klopp L et al (1998) Clinical features of trigeminal nerve sheath tumor in 10 dogs. JAAHA 34 (1), 19-25 PubMed.
  • Carpenter J L, King Jr N W & Abrams K L (1987) Bilateral trigeminal nerve paralysis and Horner's syndrome associated with myelomonocytic neoplasia in a dog. JAVMA 191 (12), 1594-6 PubMed.
  • Christopher M M, Metz A L, Klausner J et al (1986) Acute myelomonocytic leukemia with neurologic manifestations in the dog. Vet Pathol 23 (2), 140-7 PubMed.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!


To show you are not a Bot please can you enter the number showing adjacent to this field