This is not adequately explained by a simple shoulder problem or isolated cervical radiculopathy, because symptoms involve both the left upper and lower limb. A cervical root lesion may cause arm pain/tingling but should not produce same-side leg sensory symptoms.
Further management: urgent same-day evaluation in the emergency department or by neurology. At age 17 with a new unilateral hemisensory syndrome lasting 3 days, the priority is to exclude a central nervous system lesion, including ischemia/hemorrhage, demyelination such as multiple sclerosis or transverse myelitis, focal seizure-related symptoms, migraine aura, brain/spinal mass, and less commonly functional neurological symptoms.
Immediate assessment
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Repeat complete neurological examination
- Precisely map pinprick, temperature, vibration, proprioception, and cortical sensory function.
- Check face involvement, cranial nerves, visual fields, speech, coordination, gait, Romberg, reflexes, tone, plantar responses, and a sensory level.
- Look specifically for myelopathy: hyperreflexia, clonus, extensor plantar response, hand clumsiness, gait change, urinary retention/incontinence, or constipation.
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Urgent neuroimaging
- MRI brain with diffusion-weighted imaging, with contrast if clinically indicated.
- Given arm plus leg symptoms and shoulder/neck-region pain, add MRI cervical spine, ideally with contrast if demyelination, cord inflammation, tumor, or infection is considered.
- Add MRA/CTA head-neck or MR venography if vascular dissection, arterial ischemic stroke, or cerebral venous thrombosis is suspected.
- MRI is the preferred modality for most childhood strokes, and diffusion imaging can show ischemia within hours. Bradley and Daroff's Neurology in Clinical Practice, p. 1046.
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Baseline tests
- Capillary glucose immediately.
- CBC, electrolytes, calcium, renal/liver function, ESR/CRP, pregnancy test where appropriate.
- ECG. Further coagulation, thrombophilia, autoimmune, infectious, B12, thyroid, and CSF studies should be guided by neurology and imaging findings.
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Specialist referral
- Discuss urgently with pediatric neurology/neurology and admit or observe if the sensory deficit is objectively present, persistent, evolving, or imaging cannot be promptly obtained.
Red flags requiring immediate escalation
Treat as an emergency if any appear: weakness, facial droop, speech or vision change, severe sudden headache, seizures, altered consciousness, ataxia, progressive symptoms, neck trauma/manipulation, fever, a sensory level, hyperreflexia, or bowel/bladder dysfunction.
Do
not simply prescribe analgesics/physiotherapy and review later before excluding a central cause. NICE specifically lists age under 20, gait disturbance, limb clumsiness/weakness, brisk reflexes, extensor plantars, and new bowel/bladder disturbance as concerning features in suspected cervical radiculopathy, and recommends stroke/TIA-style assessment for sudden unilateral sensory symptoms in people over 16. See the
NICE neurological referral guidance.