SUNCT Syndrome vs. Trigeminal Neuralgia
A 55-year-old man presents with severe, electric shock-like pain attacks on the right side of his face, lasting 5-10 seconds, occurring 20-30 times per day. The pain is located in the right orbital and temporal region and is accompanied by tearing, redness of the eye, and nasal congestion. Attacks are triggered by touching his face or chewing. He has a history of hypertension and takes amlodipine. Neurological exam is normal. MRI of the brain is normal.
1. What is the differential diagnosis, and which features help distinguish between them?
Read the worked answer
The differential includes trigeminal neuralgia (TN) and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). Both cause short, severe unilateral attacks. However, SUNCT is characterized by prominent cranial autonomic symptoms (tearing, conjunctival injection, nasal congestion) and attacks are typically shorter (seconds) and more frequent. TN attacks are also short but lack autonomic features and are often triggered by innocuous stimuli. The presence of autonomic symptoms strongly favors SUNCT. The normal MRI and neurological exam rule out secondary causes like tumor or multiple sclerosis. The patient's age and hypertension are not directly relevant but can be comorbid. The key distinguishing feature is the autonomic symptoms, which are mandatory for SUNCT diagnosis.
2. How would you manage this patient acutely and prophylactically?
Read the worked answer
For acute attacks, there is no highly effective abortive treatment; however, subcutaneous sumatriptan or intranasal lidocaine may be tried, though evidence is limited. Prophylactically, lamotrigine is first-line for SUNCT, starting at 25 mg daily and titrating slowly to effect (typically 100-200 mg/day). Other options include gabapentin, topiramate, or carbamazepine, but lamotrigine has the best evidence. If refractory, consider greater occipital nerve block or deep brain stimulation. For TN, carbamazepine would be first-line, but given the autonomic features, SUNCT is more likely. It is crucial to reassess diagnosis if treatment fails. Patient education about the condition and avoiding triggers is important.