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997.e2 Trigeminal Neuritis

Trigeminal Neuritis Client Education
Sheet
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observed, presumably because the post-
BASIC INFORMATION
ganglionic sympathetic axons course with • CT or MRI of the brain: within normal
limits
Definition the ophthalmic branch of the trigeminal • Trigeminal nerve biopsy: not recommended
The idiopathic, self-limited inflammatory condi- nerve.
tion involves the motor and sensory branches of TREATMENT
the trigeminal nerve and occasionally involves DIAGNOSIS
the sympathetic innervation to the eye (i.e., Treatment Overview
Horner’s syndrome). Diagnostic Overview Spontaneous resolution usually occurs in 2-3
The diagnosis is based on characteristic weeks with no treatment.
Synonym clinical signs, absence of other neurologic
Dropped jaw deficits, and elimination of the possibility of Acute General Treatment
orthopedic (mandibular, temporomandibular • Maintenance of hydration and alimentation
Epidemiology joint) disorders. Advanced diagnostic testing is is critical.
SPECIES, AGE, SEX generally reserved for cases showing additional • Percutaneous esophagostomy or gastrostomy
Dogs most commonly affected; rare in cats or unusual neurologic deficits, when spontane- may be helpful in severe cases (pp. 1106 and
ous resolution does not occur, or if rabies is 1109).
GENETICS, BREED PREDISPOSITION possible (quarantine/euthanasia).
No sex or breed predisposition; golden retrievers Chronic Treatment
may be overrepresented. Differential Diagnosis Signs typically resolve spontaneously in 2-3
• Rabies weeks but in some cases take months to fully
RISK FACTORS • Traumatic mandibular injury normalize.
Other immune-mediated disease • Inflammatory or infectious central nervous
system (CNS) disease Nutrition/Diet
ASSOCIATED DISORDERS • Will most likely need a slurry or canned
Possible paraneoplastic association Initial Database food gruel in the immediate period because
• CBC, serum chemistry profile, urinalysis: the patient is unable to close the mouth but
Clinical Presentation usually within normal limits the tongue is still functional
DISEASE FORMS/SUBTYPES • Screening for infectious diseases such as • Clinical signs should resolve in 3 weeks.
Bilateral paralysis of the masticatory muscles protozoal, fungal, and viral diseases is rec-
that primarily affects the mandibular branch ommended as clinically and geographically Behavior/Exercise
of the trigeminal nerve appropriate. Encourage strengthening of the muscles by
using a tennis ball to chew on.
HISTORY, CHIEF COMPLAINT Advanced or Confirmatory Testing
• Acute or subacute onset of an inability to Unnecessary in most cases Possible Complications
close the mouth • Cerebrospinal fluid (CSF) analysis may be • Dehydration
• The dog cannot prehend food, may hyper- normal or show mild increases in protein • Weight loss
salivate, and has difficulty drinking water. concentration. Lymphocytic pleocytosis is
rarely observed. Recommended Monitoring
PHYSICAL EXAM FINDINGS • Electromyography may reveal increased • Hydration status
• Bilateral paralysis of the masticatory muscles insertional activity and other mild changes. • Food intake
• Affected dogs are bright and alert and do not
appear as though they are in pain. Most have
no other detectable neurologic abnormalities.
○ In some cases, there is decreased facial sen-
sation bilaterally, and Horner’s syndrome
may be observed.
• Trismus/inability to open the mouth does
not occur with trigeminal neuritis.
Etiology and Pathophysiology
• Most common neurologic cause of an
inability to close the mouth in the dog
• Cause is unknown, but extensive bilateral
nonsuppurative inflammation, demyelin-
ation, and in some cases, axonal degeneration
of all portions of the trigeminal nerve and
its ganglion, with no brainstem lesions, have
been reported at necropsy.
• Complete recovery is observed in 2-3 weeks
(rarely takes several months), with no drug
therapy being useful.
• Facial sensation is usually preserved. TRIGEMINAL NEURITIS Trigeminal neuritis patient exhibits the classic dropped jaw appearance and partial
Occasionally, Horner’s syndrome may be Horner’s syndrome.

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