A transformation of trigeminal neuralgia into SUNCT/SUNA: A case report and literature review

IntroductionTrigeminal neuralgia and Short-lasting Unilateral Neuralgiform Headache with Conjunctival injection and Tearing (SUNCT)/Short-lasting Unilateral Neuralgiform Headache Attacks with Cranial Autonomic Symptoms (SUNA) are characterized by similar clinical manifestations, which may lead to diagnostic confusion. However, the transformation of trigeminal neuralgia into SUNCT/SUNA is a rare phenomenon. This report describes a case of trigeminal neuralgia transformation into SUNCT/SUNA due to neurovascular compression and reviews all previously published cases of trigeminal neuralgia to SUNCT/SUNA transformation in the literature.Case presentationA 49-year-old Thai male patient presented with progressive right facial pain for a period of three months. One year prior, he developed trigeminal neuralgia along the maxillary branch of the trigeminal nerve, characterized by electrical shock-like pain in the right upper molar, exacerbated by eating. His symptoms were effectively managed with carbamazepine. Nine months later, he began experiencing recurrent electrical shock-like pain along the ophthalmic division of the right trigeminal nerve, accompanied by lacrimation, which failed to respond to continued treatment with carbamazepine. Three months prior to presentation, his symptoms evolved into SUNCT/SUNA, characterized by electrical shock-like pain in the right periorbital area and conjunctival injection, lacrimation. Neuroimaging revealed high-grade neurovascular compression of the right trigeminal nerve by the right superior cerebellar artery. The patient's symptoms resolved following microvascular decompression.ConclusionClinicians should be aware that patients with longer disease duration of trigeminal neuralgia who develop new neuralgic pain in the ophthalmic branch division with mild autonomic symptoms may be at risk for transformation into SUNCT/SUNA.