A 61-year-old man with a history of a stable C1–C3 cervical cord lesion (clinically isolated syndrome [CIS] with cervical myelopathy) and chronic left-sided radiculopathy was referred to the headache clinic with a 1-year history of bilateral occipital and upper cervical pain, worse on the right. The CIS presented with acute right shoulder pain and paresthesia affecting the lateral and anterior forearm, and at the same time, he developed a continuous dull, pressure-like headache radiating from the occipital ridge to the temporal region. The headache was aggravated by movement and prolonged neck posturing, with no pain-free periods. He denied photophobia, phonophobia or nausea, and the pain was not associated with Valsalva maneuvers, ipsilateral autonomic features or orthostatic changes.

His current medications included pregabalin 75 mg twice daily, which partially relieved his arm neuropathic and radicular symptoms but had no effect on his headache or neck pain. Over-the-counter ibuprofen, taken as needed, provided no relief. He declined escalation of the pregabalin dose due to concerns about sedation.

On examination, he demonstrated brisk reflexes (3+) in all extremities consistent with his cervical myelopathy. Sensory testing revealed cutaneous allodynia over the right posterior cervical region, particularly at the C3 dermatome. Gentle palpation over the bilateral greater and lesser occipital nerves elicited marked tenderness (right more than left).

Cervical spine MRI at presentation demonstrated a central intramedullary T2 signal abnormality extending from C1 to C3 (Figure 1), along with multilevel foraminal narrowing at C5–C6. Brain MRI was unremarkable apart from scattered nonspecific white matter changes (not shown). There was no history of optic neuritis or other clinical demyelinating events. Serologic testing for aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies was negative, and CSF analysis revealed no oligoclonal bands. Repeat cervical spine MRI performed 10 months later (Figure 2) showed significant interval improvement in the spinal cord lesion without new or enhancing lesions. In the absence of clinical or radiological progression, the findings were most consistent with a clinically isolated syndrome without evolution into multiple sclerosis. He had previously been evaluated for giant cell arteritis; inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) were normal. Electromyography revealed chronic left C6–C7 radiculopathy and left ulnar neuropathy.

Figure 1. Cervical spinal cord MRI imaging at presentation. At presentation, a short tau inversion recovery MRI sequence demonstrated (A) a sagittal view with abnormal intramedullary T2 hyperintensity extending from the C1–C2 to C3 levels, associated with mild cord expansion, and (B) a corresponding axial T2-weighted image at the level of C2 showing central intramedullary T2 hyperintensity. Post-contrast sagittal T1-weighted fat-saturated images demonstrated no evidence of enhancement (not shown).

Figure 2. Follow-up cervical spine MRI at 10 months. Follow-up imaging at 10 months demonstrated (A) short tau inversion recovery images showing faint residual intramedullary T2 hyperintensity with significant interval improvement compared to initial imaging and (B) corresponding axial T2-weighted image at the level of C2 showing marked reduction in central T2 hyperintensity.

The clinical presentation was consistent with cervicogenic headache (CGH), supported by fulfillment of the International Classification of Headache Disorders, 3rd edition (ICHD-3)^{Reference Olesen, Bendtsen, Dodick, Ducros, Evers, First and Goadsby1} diagnostic criteria. His headache developed in close temporal relation to a documented cervical spinal cord lesion and was consistently aggravated by neck movement and sustained posturing. Examination revealed marked tenderness over the occipital nerves and cutaneous allodynia in the upper cervical dermatomes, and MRI confirmed structural cervical pathology capable of causing headache. Although the pain did not meet ICHD-3 criteria for occipital neuralgia (ON), its distribution and nerve tenderness supported a trial of occipital nerve blocks.

Based on the distribution of tenderness, nerve blocks were performed using bupivacaine 0.5% (5 mg/mL). Injections were administered to the greater occipital nerves (1.5 mL bilaterally) and the lesser occipital nerves (1 mL bilaterally). Additionally, 2 mL was evenly distributed to four cervical paraspinal trigger points. The patient reported complete resolution of headache and neck pain within minutes. In addition, cutaneous allodynia improved significantly. The effect lasted approximately 3–4 weeks, with symptoms gradually returning as brief paroxysms before becoming constant again. Subsequent blocks every 3–4 weeks over the following 4 months yielded similarly consistent relief.

CGH and ON are traditionally viewed as distinct secondary headache syndromes, but in practice, the two frequently coexist or overlap. Our patient, with a stable C1–C3 spinal cord lesion, presented with chronic occipital and neck pain alongside paroxysmal episodes triggered by movement or touch. His pain characteristics – a constant dull ache with intermittent sharp flares, localized to the right occipital region and associated with cutaneous allodynia – suggest a hybrid phenotype with features of both CGH and ON.

CGH arises from musculoskeletal structures innervated by the upper cervical roots (C1–C3), with pain referred through the trigeminocervical complex to the occipital, frontal or temporal areas.^{Reference Brodal2} In contrast, ON is characterized by paroxysmal, shock-like pain along the distribution of the greater, lesser or third occipital nerves, often with localized tenderness or dysesthesia.^{Reference Olesen, Bendtsen, Dodick, Ducros, Evers, First and Goadsby1} The anatomy of these nerves, particularly the greater occipital nerve, arising from the dorsal ramus of C2, and the lesser occipital nerve, supplied by C2 and C3, links both syndromes to upper cervical spinal structures.

Importantly, lesions involving the C1–C3 spinal cord, whether due to demyelination, inflammation or degenerative disease, can result in sensitization or dysfunction of these afferents, producing overlapping headache syndromes. This relationship has been documented in multiple sclerosis and neuromyelitis optica spectrum disorder (NMOSD), where ON may occur in isolation or as an early manifestation of high cervical lesions.^{Reference Kissoon, Watson, Boes and Kantarci3} In one series, 64% of patients with demyelinating disease and ON had C2–C3 lesions.^{Reference Kissoon, Watson, Boes and Kantarci3} Similarly, Hayashi et al. reported NMOSD patients with acute occipital neuralgia and C1–C3 posterior column involvement.^{Reference Hayashi, Koumura, Yamada, Kimura, Shibata and Inuzuka4}

What distinguishes our case is the stability of the spinal cord lesion consistent with clinically isolated syndrome and the dramatic, reproducible response to occipital nerve blocks. The patient experienced near-complete relief lasting 3–4 weeks after each injection, with symptoms gradually returning as brief paroxysms before settling into a constant ache again. This temporal response supports a mixed peripheral-central pain mechanism, with nerve block addressing both peripheral sensitization (typical of ON) and central convergence pathways (implicated in CGH).

This case highlights a frequently overlooked issue: headache and neck pain are common in cervical myelopathy but often underappreciated in clinical assessment. Yet studies show up to 88% of patients with cervical radiculopathy or myelopathy experience headaches,^{Reference Riina, Anderson, Holly, Flint, Davis and Riew5–Reference Schrot, Mathew, Li, Beckett, Bae and Kim6} likely due to the same trigeminocervical convergence underlying CGH and ON. Our findings suggest that in patients with upper cervical cord lesions, even when stable and not actively inflamed, targeted occipital nerve blocks can offer meaningful symptom relief, sparing the need for systemic therapies or invasive spinal procedures.

Clinicians should consider occipital nerve blockade as a low-risk, high-yield strategy in selecting patients with upper cervical spinal cord lesions and occipital pain, especially when features of both CGH and ON are present.