Overview
This lecture covers the types, causes, clinical features, diagnosis, and treatment considerations of trigeminal neuralgia, including its differentiation from other facial pain syndromes.
Types and Presentation of Trigeminal Neuralgia
- Trigeminal neuralgia incidence is 4–20 per 100,000 people.
- Type 1 is characterized by intermittent, severe, sharp pain with pain-free intervals; often linked to vascular compression.
- Type 2 presents as constant, less severe pain with a burning quality and lacks pain-free intervals.
- Type 1 has about 28% of cases reported without neurovascular compression; Type 2 about 18%, though actual rates may be lower.
- Pain usually occurs in branches of the trigeminal nerve (V1, V2, V3), mostly on one side.
Causes and Associated Conditions
- The primary cause is believed to be vascular compression of the trigeminal nerve.
- Multiple sclerosis (MS) can cause trigeminal neuralgia due to brainstem plaques.
- 10% of MS patients experience trigeminal neuralgia, and 4% of trigeminal neuralgia patients may have MS.
- MS can coexist with vascular compression or be the sole cause.
Clinical Features & Diagnostic Clues
- Trigeminal neuralgia pain is sharp, often triggered by touching the face, cold, ice, chewing, talking, or eating.
- Severe cases can lead to significant weight loss due to inability to eat.
- Atypical facial pain differs as it is typically burning, not restricted to trigeminal nerve distribution, and can cross the midline.
Differential Diagnosis
- Trigeminal neuralgia responds well to neuroleptics (e.g., Tegretol, Neurontin).
- Atypical facial pain (afferentation pain) is less defined, more diffuse, and less responsive to these treatments.
Imaging and Preoperative Assessment
- MRI with high-resolution thin cuts (e.g., FIESTA, CISS, T1) helps identify vascular compression.
- Always check for abnormal T2 signal in the trigeminal nerve or pons to rule out intrinsic disease prior to surgery.
- Presence of T2 signal changes suggests causes other than vascular compression.
Key Terms & Definitions
- Trigeminal neuralgia — Sudden, severe facial pain due to trigeminal nerve dysfunction.
- Vascular compression — Blood vessel pressing on the trigeminal nerve, causing pain.
- Multiple sclerosis (MS) — A neurological disease that can cause nerve plaques affecting pain pathways.
- Atypical facial pain — Chronic, burning facial pain not following trigeminal nerve distribution.
- Neuroleptics — Medications used to treat trigeminal neuralgia, e.g., Tegretol (carbamazepine), Neurontin (gabapentin).
Action Items / Next Steps
- Review the clinical differences between trigeminal neuralgia and atypical facial pain.
- Study MRI imaging sequences for trigeminal neuralgia diagnosis.
- Prepare to discuss diagnostic and surgical selection criteria for trigeminal neuralgia.