What is the likely diagnosis for a 45-year-old woman with unilateral left occipital headache and posterior neck pain described as electric‑shock‑like, worsened by scalp pressure, without visual changes or neurologic deficits?

Cervicogenic Headache with Occipital Neuralgia

This presentation is most consistent with cervicogenic headache, potentially with overlapping occipital neuralgia, given the unilateral electric-shock quality pain triggered by scalp pressure, posterior neck origin, and absence of neurologic deficits. 1, 2

Key Diagnostic Features Present

The clinical picture strongly supports cervicogenic headache based on:

• Unilateral fixed pain starting in the neck and extending cranially through convergence of upper cervical nerve fibers with trigeminal pathways 1
• Electric-shock quality pain provoked by scalp pressure (allodynia) suggests occipital nerve involvement, which commonly coexists with cervicogenic headache 3, 4
• Pain worsened by touch/pressure indicates mechanical hypersensitivity characteristic of cervical spine-origin pain 1, 2
• Absence of visual disturbances, weakness, or speech deficits makes primary neurologic catastrophe (stroke, mass lesion) unlikely 5

Critical Red Flags to Exclude First

Before proceeding with cervicogenic headache management, you must actively exclude:

• Subarachnoid hemorrhage: While "worst headache of life" is classic, the electric-shock quality and scalp tenderness make this less likely; however, if this is truly a new thunderclap headache, obtain non-contrast head CT immediately 5
• Arterial dissection: Unilateral neck pain with headache warrants consideration, though absence of Horner syndrome or focal deficits reduces likelihood 2
• Spontaneous intracranial hypotension: Ask specifically if headache improves >50% within 2 hours of lying flat 2
• Postural tachycardia syndrome: Perform standing test to assess for heart rate increase >30 beats/minute 2

Physical Examination Findings to Confirm

Examine for cervicogenic headache diagnostic criteria:

• Cervical spine and paraspinal muscle tenderness on palpation, particularly C2-C7 levels and suboccipital region 1, 2
• Reduced cervical range of motion with pain provoked by neck movements (not just posture) 1, 2
• Digital pressure over upper nuchal trigger points reproduces the spontaneous pain pattern 6
• Pain with sustained awkward head positions 1

Imaging Recommendations

Do not obtain imaging initially unless red flags are present. 5, 2

• Routine MRI or CT is not indicated for cervicogenic headache because degenerative changes are present in 85% of asymptomatic individuals over 30 years and correlate poorly with symptoms 5, 2
• Cervical disc bulges and degenerative disease show no difference between symptomatic patients and controls 5
• Reserve MRI cervical spine without contrast for symptoms persisting beyond 6-8 weeks despite appropriate conservative therapy 2, 7
• Obtain immediate MRI if red flags present: constitutional symptoms, elevated inflammatory markers, known malignancy, immunosuppression, IV drug use, intractable pain, progressive neurological deficits, or vertebral body tenderness 2, 7

Treatment Algorithm

First-Line: Conservative Management

Physical therapy is the primary recommended treatment, focusing on cervical spine mobilization, stabilization, and motor control exercises 2

• Manual therapy combined with motor control exercises represents the most effective intervention with long-term maintained results 2
• Include cervical-scapular strength and stability exercises 2
• Consider aerobic exercise or progressive strength training 2

Second-Line: Diagnostic and Therapeutic Nerve Blocks

Greater occipital nerve block serves dual diagnostic and therapeutic purposes 2, 3

• Positive response to anesthetic blockade of affected cervical structures that eliminates frontal pain confirms cervical origin 1
• Provides short-term pain relief while conservative measures take effect 2, 8
• Common pitfall: Nerve blocks are also effective in migraine, so false-positive results can occur 4

Third-Line: Interventional Procedures for Refractory Cases

If symptoms persist despite 6-8 weeks of conservative therapy:

• Pulsed radiofrequency (PRF) of occipital nerves provides greater long-term pain control than nerve blocks alone 8
• Radiofrequency ablation of cervical facet joints can result in improvement for over 1 year 8
• Percutaneous interventions (facet joint injections, cervical epidural steroid injections) offer both diagnostic confirmation and therapeutic benefit 2

Fourth-Line: Neuromodulation for Severe Refractory Cases

Occipital nerve stimulation (ONS) is reserved for patients who have failed conservative therapies and interventional procedures 2, 8

• FDA-approved wireless peripheral nerve stimulation systems now have expanded indication for headache and axial neck pain 2
• Overall evidence level remains low due to limited dedicated devices and insurance coverage 2

Common Diagnostic Pitfalls to Avoid

• Do not rely on provocative cervical injections (discography, anesthetic facet/nerve blocks) for diagnosis as they frequently produce false-positive results due to anesthetic leakage 5, 2
• Do not interpret degenerative imaging findings as causative without clinical correlation 5, 2
• Do not confuse occipital neuralgia with cervicogenic headache: Occipital neuralgia refers to pain restricted to nerve distribution with paroxysmal lancinating quality, while cervicogenic headache spreads to oculo-fronto-temporal area 6, 4
• Do not miss coexisting migraine: Cervicogenic headache and migraine can overlap, with cervical triggers potentially inducing migraine in some patients 6