Secondary Trigeminal Neuralgia

Secondary trigeminal neuralgia is facial pain resulting from an identifiable structural lesion affecting the trigeminal nerve, such as tumors, multiple sclerosis plaques, vascular malformations, or skull base abnormalities.

Unlike classical trigeminal neuralgia (usually caused by neurovascular conflict), secondary forms involve direct nerve damage or displacement.

• Tumors:
  1. Trigeminal schwannoma
  2. Meningioma
  3. Epidermoid cyst
  4. Brain metastases
  5. Nasopharyngeal carcinoma
• Demyelinating disease:
  1. Multiple sclerosis (especially with pontine plaques)
• Vascular malformations:
  1. Arteriovenous malformations
• Trauma or skull base fractures
• Infectious/inflammatory:
  1. Sarcoidosis
  2. Lyme disease
  3. Chronic meningitis

• Pain: may be similar to classical TN (sharp, paroxysmal) but often more constant or burning
• Sensory loss: common (hypoesthesia or anesthesia in trigeminal distribution)
• Motor involvement: possible if V3 affected (e.g., jaw weakness)
• Bilateral symptoms: more suggestive of demyelinating causes
• Associated neurological signs: depending on the lesion's location

• MRI with contrast: essential to identify underlying cause (tumor, plaque, vascular lesion)
• CT: useful for bone pathology or trauma
• CSF analysis: if infectious or inflammatory etiology is suspected
• Neurological exam: look for hypoesthesia, corneal reflex changes, or other cranial nerve deficits

1. Treat the underlying cause:

• Surgery, radiosurgery, or radiotherapy for tumors
• Disease-specific treatment for MS, infections, or inflammation
• Antiepileptic drugs for pain (e.g., carbamazepine, oxcarbazepine, gabapentin)

2. Pain management:

• Medical therapy first-line
• Interventional options (nerve blocks, radiofrequency ablation) if pain is refractory

Depends on the underlying cause and the response to treatment. In some cases (e.g., MS-related TN), pain can be recurrent and difficult to manage.

• MRI should be performed in all patients with trigeminal neuralgia and any of the following:
  1. Atypical pain characteristics
  2. Sensory loss
  3. Bilateral symptoms
  4. Young age (<50 years)