Diagnosis

Trigeminal neuralgia

Etiology

Cause

• Idiopathic: Unknown cause [woe]

• Neurovascular conflict --> superior cerebellar artery compress the trigeminal nerve root [29y]

• Secondary (15%): multiple sclerosis, tumor, or arteriovenous malformation

Pathophysiology [29y]

1. The trigeminal nerve is responsible for the sensory and motor supply of the face

   • Ophthalmic (V1): eye, upper eyelid, and forehead

   • Maxillary (V2): lower eyelid, cheek, nostril, upper lip, and upper gingivae

   • Mandibular (V3): lower lip, lower gingivae, jaw, and the muscles of mastication

2. Trigeminal nerve compression --> subsequent nerve demyelination

3. Hypothesis: ectopic impulse generation induced by the demyelinated lesion without using synapses or neurotransmitters

4. Light tactile stimulation --> Shock-like pains in the facial trigger zone

Complications [29y]

• Psychology:

  • Depression

  • Social withdrawal

  • Isolation

• Neurology:

  • Facial numbness

  • Corneal anesthesia

  • Jaw weakness

  • Intractable facial dysesthesia (anesthesia dolorosa)

• Side effects from treatment: Anticonvulsant, surgery 

Epidemiology

Incidence per 100.000 [5t5][ieh][woe]

Approach

Clinical diagnosis

• Sudden, intense, shock-like or stabbing pain

• Typically on one side of the face

• Burning, throbbing, numbness, tingling, or dull aching sensation in between attacks

The diagnostic criteria established by the ICHD-3 [29y]

1. Recurrent paroxysms of unilateral facial pain in the distribution of the trigeminal nerve

2. Pain has all the following characteristics:

   • Pain lasting a fraction of a second to about 2 minutes

   • Pain with severe intensity

   • Electric shock-like, sharp, or shooting pain 

3. Innocuous stimuli within the affected nerve distribution precipitate the pain

4. No alternative ICHD-3 diagnosis better explains the symptoms.

Treatment

1. Anticonvulsant medicines: assessments of therapy 2 weeks after initiation

   • 1st line: Carbamazepine or oxcarbazepine [29y]

   • 2nd line: Gabapentin, clonazepam, lamotrigine, phenytoin, and valproic acid

2. Other medications: Baclofen and Botulinum toxin A

3. Surgery:

   • Microvascular decompression

   • Rhizotomy (rhizolysis)

   • Peripheral neurectomy and nerve blockade

   • Deep brain stimulation

   • Radiosurgery

Differential diagnoses

Cerebral aneurysm, Cluster headache, Dental infection, Herpes zoster, Intracranial hemorrhage, Migraine, Multiple sclerosis, Subarachnoid hemorrhage, Temporomandibular syndrome