Trigeminal neuralgia

Background

Trigeminal nerve anatomy.

Dermatome distribution of the trigeminal nerve: V1 (green), V2 (red), and V3 (yellow).

• Also known as tic doulourex

Clinical Features

• Paroxysms of severe unilateral pain in trigeminal nerve distribution lasting only seconds
• Normal neuro exam
• No pain between paroxysms
• Variant with headache
• More common in Middle aged women
• Frequently triggered by minimal stimuli (e.g. light touch, gentle breeze)

Differential Diagnosis

Headache

Common

• Migraine headache
• Tension headache
• Cluster headache

Killers

• Meningitis/encephalitis
  • Neoplastic meningitis
• Myocardial ischemia
• Retropharyngeal abscess
• Intracranial Hemorrhage (ICH)
  • SAH / sentinel bleed
• Acute obstructive hydrocephalus
• Space occupying lesions
• CVA
• Carbon monoxide poisoning
• Basilar artery dissection
• Preeclampsia
• Cerebral venous thrombosis
• Hypertensive emergency
• Depression

Maimers

• Giant cell arteritis of temporal artery (temporal arteritis)
• Idiopathic intracranial hypertension (Pseudotumor Cerebri)
• Acute Glaucoma
• Acute sinusitis
• Cavernous sinus thrombosis or cerebral sinus thrombosis
• Carotid artery dissection

Others

• Trigeminal neuralgia
• TMJ pain
• Post-lumbar puncture headache
• Dehydration
• Analgesia abuse
• Various ocular and dental problems
• Herpes zoster ophthalmicus
• Herpes zoster oticus
• Cryptococcosis
• Febrile headache (e.g. pyelonephritis, nonspecific viral infection)
• Ophthalmoplegic migraine
• Superior Vena Cava Syndrome

Aseptic Meningitis

• Viral
  • Varicella
  • Herpes
  • Enterovirus
  • West Nile
• Tuberculosis
• Lyme disease
• Syphilis
• Leptospirosis
• Fungal (AIDS, transplant, chemotherapy, chronic steroid use)
• Noninfectious
  • Sarcoidosis
  • Vasculitis
  • Connective tissue disease
  • Drug induced aseptic meningitis

Facial paralysis

• Bell's palsy
• CVA
• Trigeminal neuralgia
• Tick paralysis
  • Lyme disease
• Herpes zoster oticus (Ramsay Hunt syndrome)
• CNS tumor
  • Acoustic neuroma or other cerebellopontine angle lesions
  • Meningioma
  • Cerebellar pontine angle
  • Facial nerve schwannoma
  • Parotid
  • Sarcoma
• Anesthesia nerve blocks
• Cerebral Aneurysms (vertebral, basilar, or carotid)

Evaluation

• Sensory loss, bilateral involvement, and younger age (<40) are associated with a higher risk of secondary TN, but their absence does not rule out secondary TN
• Consider CT/MRI in these patients to rule out structural etiology
• <5% of patients have V1 distribution, examine carefully for zoster in these patients

Management

Phenytoin

• 250mg IV to abort an acute attack
• Relief lasts from four hours to three days
• Fosphenytoin seems to work similarly

Carbamazepine

• First-line agent with 75% success rate initially
• Proposed Mechanism: Decreases the response of neurons to peripheral stimulation
• Started at 100mg one to two times per day
• Increase by 100-200mg every 3 days
• Usual maintenance dose is 400-800mg (rare >1500mg)
• Metabolized by liver (cytochrome P450)
  • LFTs monitored on outpatient basis
• Pain relief occurs within several hours to days (94% within 48 hours)
• Target serum concentration is 24-43 μmol/L
  • If unsuccessful, phenytoin 200-400mg/day is used in combination

Other agents

• Baclofen, clonazepam, valproic acid, lamotrigine, gabapentin, oxcarbazepine, topiramate

Surgery

• Posterior fossa microvascular decompressive surgery
  • Approximately 50% of patients will require surgery
• Successful in 70% of patients

Disposition

• Typically outpatient

See Also

• Headache

References

• J Pain Symptom Manage 2001; 21(6):506-510.