Unmasking a Cerebral Arteriovenous Malformation Presenting as a Chronic Migraine-Type Headache at a District General Hospital

A female in her 50s was referred by her General Practitioner (GP) to our Same Day Emergency Care (SDEC) unit due to an unresponsive migraine attack. Associated features included nausea, photophobia, phonophobia, intermittent visual aura, and unintentional weight loss over the last two weeks. Arteriovenous malformations (AVMs) are rare vascular anomalies, with a prevalence of approximately 18 per 100,000 individuals. Although often asymptomatic, they may present atypically with migraine-like headaches, posing a diagnostic challenge. Her full neurological assessment, including cranial nerves, cerebellar function, and motor and sensory systems, was unremarkable. However, neuroimaging revealed a large, unruptured, complex AVM in the left parieto-occipital region, associated with cerebral oedema and midline shift. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) confirmed a Spetzler-Martin Grade III AVM. Her imaging was urgently discussed with the Neurosurgery Department at Oxford University Hospitals for further intervention, as our institution does not have a neurosurgery department being a district general hospital. The multidisciplinary team (MDT) recommended radiosurgery, and her symptoms resolved after the intervention. This case illustrates the importance of neuroimaging in patients with refractory or unresponsive migraine, enabling early detection of serious intracranial pathology such as AVMs. It also highlights the value of timely specialist referral, inter-hospital collaboration, and patient-centred care in optimising outcomes.