DESCRIPTION

• The trigeminal nerve (cranial nerve [CN] V) innervates the face, oral mucosa, nasal mucosa, and cornea with its sensory fibers
• Trigeminal neuralgia is also known as tic douloureux:
  • Tic = spasmodic muscular contraction or movement
  • Douloureux = painful
• Usually occurs in patients > 50 yr of age
• Facial pain syndrome recognizable by history alone
• Classical:
  • Paroxysmal attacks of unilateral (uncommonly bilateral) pain affecting 1 or more divisions of the trigeminal nerve
  • Has 1 of the following characteristics:
    • Superficial, sharp, or stabbing pain
    • Precipitated from trigger areas or factors
  • Lasts for < 1 sec–2 min
  • Episodes are stereotyped in each individual
  • No clinically evident neurologic deficit
  • Not caused by another disorder
• Symptomatic:
  • Same as above but a causative lesion (not vascular compression) is identified
• Most common age group is 50–60 yr
• Females > males

ETIOLOGY

• Mechanism of pain production remains controversial; accepted theory suggests:
  • Demyelination of CN, leading to ectopic stimulation and pain:
    • Demyelination caused by tortuous or aberrant vascular compression of nerve root
    • 80–90% of classical trigeminal neuralgia have compression
    • Superior cerebellar artery is the most common (75%)
    • Anterior inferior cerebellar artery (10%)
• Secondary causes:
  • Herpes zoster
  • Multiple sclerosis
  • Space-occupying lesions:
    • Cerebropontine angle tumor
    • Aneurysm
    • Arteriovenous malformation

[Outline]

• DESCRIPTION
• ETIOLOGY

SIGNS AND SYMPTOMS

• Brief, intense, recurrent sharp pain
• Often described as "electric like"
• Unilateral in the distribution of a branch of the trigeminal nerve:
  • Can occur in all 3 nerves: Maxillary > mandibular > ophthalmic
• More common on right side of face
• May occur without provocation, but triggers can be produced by talking, smiling, chewing, brushing teeth, shaving, or touching the face:
  • Touch and vibration are the most common stimulus
• Can occur infrequently or hundreds of times per day
• No pain between episodes, although chronic cases may complain of a continuous ache

History

• Rule out possible symptomatic causes with the following atypical features:
  • Abnormal neurologic exam
  • Abnormal oral/dental exam
  • Abnormal ear exam or hearing loss
  • Symptoms of dizziness, vertigo, visual changes, or numbness
  • Pain lasting > 2 min
  • Not in trigeminal nerve distribution

Physical Exam

• Physical exam findings are normal; if abnormality found, consider other cause
• Carefully examine head and neck, with emphasis on CNs
• Patient's report of pain following stimulation of a trigger point is pathognomonic

ESSENTIAL WORKUP

• Diagnosis is made clinically
• Clinical features to differentiate classical and symptomatic disease:
  • Age on onset < 50 yr
  • Sensory deficits
  • Bilateral involvement

DIAGNOSIS TESTS & INTERPRETATION

Lab

No specific lab tests apply

Imaging

• Patients with characteristic history and normal neurologic exam may be treated without further workup
• If dental problems are suggested, dental radiographs may be useful
• MRI brain/CT head may be useful if multiple sclerosis or tumor is suggested:
  • May be useful in initial presentation

DIFFERENTIAL DIAGNOSIS

• Multiple sclerosis
• Temporomandibular joint syndrome
• Glossopharyngeal neuralgia
• Compression of trigeminal root by tumors
• Dental problems/pain
• Cluster headache
• Postherpetic neuralgia
• Sinusitis
• Otitis media
• Temporal arteritis

[Outline]

• SIGNS AND SYMPTOMS
• ESSENTIAL WORKUP
• DIAGNOSIS TESTS & INTERPRETATION
• DIFFERENTIAL DIAGNOSIS

ED TREATMENT/PROCEDURES

• Appropriate pain relief
• Medical therapy:
  • Carbamazepine most commonly used
  • Other antiepileptics show some support as adjuvants for refractory pain.
• May need neurosurgical evaluation for treatment and/or exploration

MEDICATION

First Line

Carbamazepine: 200–800 mg/d PO BID

Second Line

• Gabapentin: Start 300 mg PO QD
• Lamictal: Start 25 mg PO QD
• Oxcarbazepine: 450–1,200 mg PO BID; start 300 mg PO BID
• Phenytoin: 300–400 mg/d div. QD–TID
• Valproic acid: Start 250 mg PO BID

[Outline]

• ED TREATMENT/PROCEDURES
• MEDICATION

DISPOSITION

Admission Criteria

• Trigeminal neuralgia with presence of other focal neurologic findings
• Positive CT or MRI studies may require emergent neurologic or neurosurgical consultation
• Refractory or recurrent trigeminal neuralgia not responding to outpatient pain management or anticonvulsant therapy:
  • May require admission for surgical intervention and ablation of the trigeminal nerve

Discharge Criteria

Patients without any focal neurologic findings and improved pain control in the ED may be managed as outpatients.

Issues for Referral

• Surgical therapy may be indicated for those who fail medical treatment
  • Pain relief in 85–90%
• Referral to a pain management center may be helpful in cases of refractory pain
• Anesthetic blocks of the trigeminal ganglion may be helpful

FOLLOW-UP RECOMMENDATIONS

• Follow up with PCP or neurologist for treatment
• Referral to a neurosurgeon may be indicated for refractory pain:
  • Percutaneous vs. open surgical treatment

[Outline]

• DISPOSITION
• FOLLOW-UP RECOMMENDATIONS

• Unilateral, paroxysmal, and sharp/stabbing facial pain, following a portion of CN V distribution
• Trigger points are pathognomonic
• Do not miss an alternate (nonvascular) cause of nerve compression, such as CNS mass or aneurysm
• Carbamazepine is the most common treatment

ICD9

• 053.12 Postherpetic trigeminal neuralgia
• 350.1 Trigeminal neuralgia

ICD10

• B02.22 Postherpetic trigeminal neuralgia
• G50.0 Trigeminal neuralgia

[Outline]

• ICD9
• ICD10

• Garg RK, Malhotra HS, Verma R. Trigeminal neuralgia. J Indian Med Assoc. 2011;109:631–636.
• Krafft RM. Trigeminal neuralgia. Am Fam Physician. 2008;77:1291–1296.
• Siqueira SR, Teixeira MJ, Siqueira JT. Clinical characteristics of patients with trigeminal neuralgia referred to neurosurgery. Eur J Dent. 2009;3:207–212.
• Wolfson AB, Hendey GW, Ling LJ, et al., eds. Harwood-Nuss' Clinical Practice of Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010.

Adam Z. Barkin