Secondary Trigeminal Neuralgia (Investigational Adjunct)

Patient Summary

Is this FDA-cleared for this use?

Not FDA-cleared for trigeminal neuralgia. FDA cleared medicinal leeches only for venous congestion in microsurgical reconstruction (K040187, June 2004). Use for secondary trigeminal neuralgia is investigational.

What evidence exists?

Tier C (investigational). Only case reports; there are no randomized controlled trials. Evidence-based therapy for trigeminal neuralgia: carbamazepine or oxcarbazepine as first-line (AAN-endorsed), with lamotrigine, baclofen, or gabapentin as alternatives. Microvascular decompression surgery in selected fit patients (long-term pain relief >70 percent). Gamma knife radiosurgery and percutaneous procedures (glycerol injection, balloon compression, radiofrequency thermocoagulation) for medically refractory disease. Secondary causes (multiple sclerosis, tumor) require treatment of the underlying disease.

Main risks

• Bleeding from bite sites for 6 to 24 hours after detachment
• Trigger of acute trigeminal pain attack at bite locations on the face
• Local skin infection or, rarely, Aeromonas infection on the face
• Allergic reaction to leech saliva (uncommon)
• Post-inflammatory hyperpigmentation or scarring on the face
• Risk if leech placed too close to the eye or ophthalmic branch
• Delay of carbamazepine, microvascular decompression, or workup for secondary causes
• Risk of missed multiple sclerosis or tumor as cause of secondary trigeminal neuralgia

Who should not consider this

• Patients who have not been worked up for multiple sclerosis or tumor (MRI required)
• Patients with active herpes zoster of the trigeminal nerve
• Patients with eye involvement or first-division (V1) trigeminal pain (specialty care)
• Patients on anticoagulants, with hemophilia, or with severe anemia
• Patients who have not tried carbamazepine or oxcarbazepine
• Patients with darker Fitzpatrick skin types at high PIH risk on the face

What to ask your clinician

• Have I had an MRI brain to rule out multiple sclerosis or tumor?
• Have I tried carbamazepine or oxcarbazepine at therapeutic doses?
• Am I a candidate for microvascular decompression or gamma knife radiosurgery?
• What evidence specifically supports leech therapy for trigeminal neuralgia?
• What is the risk of triggering a pain attack with facial leech bites?
• Are leeches from an FDA-registered supplier and used only once?
• What is the cost and is it covered by insurance? (typically not covered)

When to seek urgent care

• New double vision, eye pain, or vision loss (cranial nerve or eye involvement)
• Sudden severe facial weakness or numbness (possible stroke or tumor progression)
• New limb weakness, balance problems, or vision changes (possible MS exacerbation)
• Spreading redness, warmth, pus, or red streaks (cellulitis)
• Fever above 38.0 C / 100.4 F or chills
• Bleeding from a bite site lasting more than 24 hours
• Hives, facial or tongue swelling, throat tightness, or breathing difficulty