Trigeminal neuritis

From Dog

Trigeminal neuritis is a rare neurological disease of dogs characterized by inflammatory disease of cranial nerve V (trigeminal nerve) with subsequent jaw paralysis[1].

This disease is usually of idiopathic origins and c an affect any breed of dog.

Clinically affected dogs present with polydipsia, trismus, ptyalism and mild dysphagia, although some dogs are usually able to swallow normally.

Unilateral Horner's syndrome has also been reported. Facial sensations are usually normal, and neurogenic atrophy of the masticatory muscles may also be present, resulting in trismus[2].

Diagnosis is usually based on presenting clinical signs and exclusion of other causes. Muscle biopsies are usually definitive and show nonsuppurative inflammation and demyelination in the motor branches of the trigeminal nerve involving demyelination with some axonal loss.

A differential diagnosis would include Clostridium tetani, rabies, temporomandibular joint ankylosis due to fractures, masticatory muscle myositis, peripheral nerve sheath tumor[3], polymyositis, mandibular osteosarcoma, trigeminal nerve paralysis and central neurological lesions, temporomandibular joint luxation and dysplasia, temporomandibular osteoarthritis, retrobulbar abscess and severe otitis externa.

Most patients respond to broad-spectrum antimicrobial therapy such as amoxycillin/clavulanate and glucocorticoids are not usually recommended.

A large bore pharyngostomy tube is usually placed in the initial few days until teh dog responds to treatment and most cases resolve in 2 - 4 weeks.

References

  1. Powell AK (1991) Idiopathic trigeminal neuritis in a dog. Can Vet J 32(5):265
  2. Braund, KB (1996) Endogenous causesof neuropathies in dogs and cats. Vet Med 740-754
  3. Schultz RM et al (2007) Magnetic resonance imaging of acquired trigeminal nerve disorders in six dogs. Vet Radiol Ultrasound 48(2):101-104