Master Trigeminal Neuralgia (Tic Douloureux) with Picmonic for Medicine

Cranial nerve V, the trigeminal nerve, originates in the pons and has both motor and sensory innervations in the face. Its three main branches, V1 (ophthalmic), V2 (maxillary), and V3 (mandibular), provide sensation to the upper third, middle third, and lower third of the face, respectively. CN V also provides sensation to the temporomandibular joint, teeth, and anterior 2/3 of the tongue.

Severe, sharp, stabbing facial pain on one side of the face in the distribution of one or more branches of the trigeminal nerve is characteristic of trigeminal neuralgia. These episodes often occur from minor stimuli, e.g., wind blowing on the face, brushing teeth, or applying face lotion, and last for several seconds to minutes.

Facial spasms of muscles in the face can occur in response to severe pain.

Secondary to the neurologic facial pain, psychological distress within a broad spectrum can occur. Symptoms can range from dysphoria to severe depression with suicidal ideation.

Trigeminal Neuralgia is rare. However, it is more common in women (2:1), who are usually >60 years old.

Trigeminal neuralgia is a clinical diagnosis and must include all of the following criteria, per the International Classification of Headache Disorders:
- Severe, acute, stabbing/electric shock-like, unilateral episodes of pain in the area innervated by one or more divisions of CN V.
- Episodes of pain last no more than 2 minutes.
- Pain triggered by innocuous stimuli.
- There is no other better explanation for the symptoms.

Neuroimaging, specifically MRI, is used to classify cases of trigeminal neuralgia according to their etiology. All patients with trigeminal neuralgia should have at least one MRI performed at diagnosis to determine the etiology. Up to 15% of cases have secondary causes of trigeminal neuralgia.

Carbamazepine is a first-line treatment for trigeminal neuralgia. Another option is oxcarbazepine. The efficacy of these anticonvulsants has been proven in several randomized controlled trials. However, these drugs are not always well tolerated and may cause hepatotoxicity or leukopenia. All patients should have intermittent labs, including CBCs and LFTs, to monitor for it.

Surgery may be indicated if pharmacological treatment fails. Procedures like transcutaneous or microvascular decompression aim to treat vascular compression of CN V nerve roots (classic trigeminal neuralgia) by injuring the sensory fibers of the trigeminal nerve, cutting off their transmission of pain.