Neuroscience · Year 2 · from Neuroscience
Case 3: Trigeminal Neuralgia
Patient Presentation
Demographics: 62-year-old female
Chief Complaint: Severe, shooting facial pain for 3 months
History of Present Illness: A 62-year-old woman presents with recurrent episodes of excruciating, electric shock-like pain on the right side of her face. The pain episodes are brief (seconds to less than 2 minutes) but occur multiple times daily. The pain is triggered by brushing her teeth, eating, talking, or even a light breeze on her face. She has identified a "trigger zone" on her right cheek that, when touched, precipitates an attack. Between attacks, she is pain-free. She has lost 10 pounds because she is afraid to eat. The pain has not responded to over-the-counter pain medications.
Physical Examination:
- Vital signs: Normal
- General: Appears anxious; avoids touching right side of face
- Neurological:
- Mental status: Normal
- Cranial nerves: Cranial nerve V examination completely normal (no sensory loss, normal corneal reflex, normal motor function); all other cranial nerves intact
- Motor, sensory, reflexes: Normal
- Dental examination: No dental pathology identified
Workup:
- MRI brain with high-resolution constructive interference in steady state (CISS) sequence: Vascular loop (superior cerebellar artery) contacting and compressing the right trigeminal nerve root entry zone; no mass lesions or demyelinating plaques
- Routine blood work: Normal
Diagnosis: Classic trigeminal neuralgia (tic douloureux) due to neurovascular compression
Treatment:
- Carbamazepine 100 mg twice daily initiated, titrated to 400 mg twice daily with good pain control
- CBC and liver function monitored (carbamazepine side effects)
- HLA-B*1502 testing performed before carbamazepine initiation (Asian ancestry screening for Stevens-Johnson syndrome risk)
- Education that surgical options (microvascular decompression, gamma knife radiosurgery) available if medication fails or intolerable
- Pain-free on carbamazepine at 6-month follow-up
Clinical Pearl: Trigeminal neuralgia is characterized by brief, severe, stereotyped pain attacks in the distribution of one or more trigeminal nerve divisions. The mandibular (V3) and maxillary (V2) divisions are most commonly affected, often with a trigger zone. Classic trigeminal neuralgia results from neurovascular compression of the trigeminal nerve root, most commonly by the superior cerebellar artery. Importantly, the neurological examination is NORMAL between attacks in classic cases. Sensory loss, young age, or bilateral symptoms suggest secondary causes such as multiple sclerosis or tumor and warrant thorough investigation.
Clinical Image
Image Description: Sagittal T2-weighted MRI of the cervical spine demonstrating a syrinx (hyperintense fluid-filled cavity) within the central spinal cord, along with Chiari I malformation showing cerebellar tonsillar herniation below the foramen magnum.
Attribution: Image from Radiopaedia (https://radiopaedia.org/), Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license.