How should I treat a 55‑year‑old patient with trigeminal neuralgia affecting the V2/V3 distribution, presenting with brief electric‑shock‑like facial pain triggered by light touch, chewing, or speaking?

Treatment of Trigeminal Neuralgia in a 55-Year-Old Patient

First-Line Pharmacologic Treatment

Start carbamazepine immediately as the gold standard first-line treatment for this patient's classical trigeminal neuralgia. 1, 2

• Carbamazepine is FDA-approved specifically for trigeminal neuralgia and is recommended by the American Academy of Neurology as the initial drug of choice. 1, 2
• Approximately 75% of patients achieve initial symptom control with carbamazepine monotherapy. 3
• The mechanism of action involves modulation of voltage-gated sodium channels, which decreases the abnormal neuronal hyperexcitability caused by demyelination at the trigeminal root entry zone. 4

Alternative First-Line Option

• Oxcarbazepine is equally effective with fewer side effects and serves as an appropriate alternative if carbamazepine is not tolerated. 1
• Common dose-limiting side effects of carbamazepine include drowsiness, headache, and dizziness, which may necessitate switching to oxcarbazepine. 1

Mandatory Diagnostic Imaging Before Escalation

Obtain brain MRI with contrast using high-resolution thin-cut sequences through the trigeminal nerve course in all patients before considering surgical intervention. 1

• The American Academy of Neurology recommends MRI for all suspected trigeminal neuralgia cases to distinguish classical TN (with neurovascular compression), secondary TN (from MS, tumors, or other structural lesions), and idiopathic TN. 5, 1
• Use 3D heavily T2-weighted sequences combined with MRA to characterize neurovascular compression, which shows 83-100% congruence with surgical findings. 1
• Pre- and post-contrast imaging provides the best opportunity to identify secondary causes such as multiple sclerosis plaques or cerebellopontine angle tumors. 1

Critical Red Flags to Exclude in This Age Group

In any patient over 50 presenting with facial pain, urgently exclude giant cell arteritis to prevent irreversible blindness. 5

• Giant cell arteritis presents as continuous dull aching temporal or jaw pain worsened by chewing, accompanied by scalp tenderness, elevated inflammatory markers (ESR/CRP), visual disturbances, fever, and diminished temporal pulse. 5
• If giant cell arteritis is suspected, initiate high-dose corticosteroids (≥40 mg prednisone daily) immediately before temporal artery biopsy. 5

Other Key Differential Diagnoses

• Trigeminal autonomic cephalgias (SUNCT/SUNA) present with up to 200 attacks daily without refractory periods, accompanied by tearing, conjunctival injection, rhinorrhea, and facial redness—features absent in classical TN. 5, 1
• Post-herpetic neuralgia causes continuous burning pain at the site of previous herpes zoster eruption with allodynia, not the paroxysmal electric shock-like quality of TN. 5, 1
• The presence of continuous pain (rather than paroxysmal attacks with mandatory refractory periods) should prompt MRI evaluation to rule out secondary causes including MS, tumors, or other structural lesions. 5

Second-Line Pharmacologic Options

If carbamazepine or oxcarbazepine fail or cause intolerable side effects, add or switch to lamotrigine, baclofen, gabapentin combined with ropivacaine, or pregabalin. 1

• These agents are supported by guideline evidence as second-line options and can be used either as monotherapy or as add-on therapy for synergistic pain control. 1, 4
• Lamotrigine is particularly effective if SUNCT/SUNA has been misdiagnosed as classical TN. 5

Surgical Referral Criteria

Obtain neurosurgical consultation early when medications become ineffective or intolerable, rather than waiting for complete pharmacologic failure. 1

• Microvascular decompression (MVD) is the preferred surgical option for patients with documented neurovascular compression on MRI who lack significant comorbidities. 1
• MVD preserves nerve integrity and achieves 70% pain-free outcomes at 10 years, though it carries a 2-4% risk of hearing loss and 0.4% mortality risk. 1
• Percutaneous ablative procedures (radiofrequency thermocoagulation, glycerol injection, balloon compression) are recommended for elderly patients or those with major comorbidities who cannot tolerate MVD. 6
• Stereotactic radiosurgery typically provides pain relief within one month but can take up to six months in some cases. 5

Emerging Adjunctive Therapy

• Botulinum toxin type A (BoNT-A) can be considered as adjunctive therapy in refractory cases where traditional medical and surgical options have failed, with subcutaneous injections providing substantial pain relief with minimal side effects (transient facial paresis). 7, 4

Common Pitfalls to Avoid

• Do not use carbamazepine for trivial aches or pains—it is specifically indicated for true trigeminal neuralgia, not as a simple analgesic. 2
• Do not delay MRI imaging; sensory deficits in the trigeminal distribution require urgent imaging to rule out secondary causes such as tumors or MS. 5, 8
• Do not mistake continuous pain for classical TN; the mandatory refractory period (pain-free interval between attacks) is pathognomonic for classical trigeminal neuralgia and distinguishes it from other facial pain syndromes. 5, 1
• Do not overlook the psychological impact—fear and depression develop early due to the unpredictable nature of attacks, significantly impacting quality of life even in early stages. 8