Trigeminal Autonomic Cephalalgias Following Unilateral Dorsolateral Medullary Infarction: A Case Series and Literature Review

Purpose: Secondary trigeminal autonomic cephalalgias (TACs) are typically associated with posterior fossa abnormalities, such as tumors and vascular malformations. However, TACs following brainstem infarctions are rarely reported. This study aimed to characterize the clinical and anatomical features of TACs after unilateral dorsolateral medullary infarction.Methods: We analyzed four patients with dorsolateral medullary infarction who developed secondary TACs, diagnosed using the International Classification of Headache Disorders, third edition criteria. All patients underwent detailed neurological examinations and neuroimaging, including diffusion-weighted magnetic resonance imaging and magnetic resonance angiography. Additionally, five published cases were identified through a literature review and analyzed in conjunction with our cohort.Results: All patients exhibited stabbing or electric shock-like pain in the ipsilateral periorbital, hemifacial, and temporal regions. Headaches developed weeks to months post-stroke with brief attacks (1–2 minutes) occurring 1–5 times daily. Lacrimation and conjunctival injection were common. Three patients were diagnosed with short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), while a fourth had short-lasting unilateral neuralgiform with cranial autonomic symptoms (SUNA). Each patient, as well as four of the five from the literature, exhibited ipsilateral facial sensory loss, suggesting involvement of the trigeminal spinal tract and nucleus. Delayed headache onset was more frequent in persistent cases.Conclusion: Headache characteristics were more consistent with SUNCT/SUNA than with typical cluster headaches. Careful neurological examination is essential to detect focal signs and guide neuroimaging for identifying secondary causes. Clinicians should consider secondary TACs in patients with new-onset SUNCT/SUNA and focal brainstem signs.