What is the best course of action for a patient experiencing widespread tingling in the lower legs, back, lower arms, and hands, with elevated inflammatory markers and no known past medical history?

Urgent Neurologic Workup for Widespread Tingling with Elevated Inflammatory Markers

This patient requires immediate evaluation for inflammatory myositis or immune-mediated polyneuropathy, with urgent creatine kinase (CK), EMG/nerve conduction studies, and MRI to differentiate between life-threatening myositis and demyelinating neuropathy.

Immediate Diagnostic Priorities

Critical Laboratory Studies

• Obtain CK level immediately to distinguish myositis (elevated CK with weakness) from polyneuropathy (normal CK with sensory symptoms) 1, 2
• Check troponin and ECG urgently because myocarditis with myositis carries high mortality and requires immediate aggressive immunosuppression 1, 2
• Measure aldolase, AST, ALT, and LDH to assess for muscle inflammation 2
• Obtain urinalysis to evaluate for myoglobinuria/rhabdomyolysis if CK is elevated 2
• Verify ESR and CRP values are truly elevated and not related to alternative infectious or inflammatory processes 1, 3

Distinguish Between Two Critical Diagnoses

If weakness is present (not just tingling):

• Perform detailed strength testing of proximal and distal muscles in all four extremities 1, 2
• True muscle weakness with elevated CK suggests immune checkpoint inhibitor-induced myositis or inflammatory myositis requiring immediate corticosteroids 1, 4
• Myositis can be fulminant and fatal, especially with cardiac involvement 1

If predominantly sensory symptoms (tingling/numbness) without significant weakness:

• Obtain urgent EMG and nerve conduction studies to evaluate for demyelinating polyneuropathy such as CIDP or Guillain-Barré syndrome 5, 6, 7
• Look for length-dependent sensory loss, areflexia, and conduction blocks on nerve studies 5, 6
• Lumbar puncture showing elevated protein with acellular CSF supports inflammatory polyneuropathy 5

Imaging Requirements

• Obtain MRI of the spine (cervical, thoracic, lumbar) with and without contrast to evaluate for vertebral osteomyelitis, epidural abscess, or spinal cord pathology given back involvement with elevated inflammatory markers 1
• MRI has 95% sensitivity for detecting spondylodiscitis and can identify epidural inflammatory changes 8
• Do not delay imaging because epidural abscess with neurologic symptoms requires emergency surgical decompression 1

Management Algorithm Based on Findings

If CK Elevated with Weakness (Myositis):

• Initiate high-dose corticosteroids immediately (prednisone 1 mg/kg/day or IV methylprednisolone) for progressive weakness 1, 2
• Hold any immune checkpoint inhibitors permanently if patient is on cancer immunotherapy 1, 2
• Ensure aggressive hydration with goal urine output >0.5 mL/kg/hour to prevent acute kidney injury from myoglobin precipitation 2
• Obtain myositis antibody panel and consider muscle biopsy if diagnosis uncertain, though do not delay treatment 1, 4
• Urgent cardiology consultation if troponin elevated, as myocarditis requires more aggressive immunosuppression and possible IVIG or plasmapheresis 1, 2

If Normal CK with Sensory Symptoms (Polyneuropathy):

• Initiate IVIG or plasmapheresis if EMG confirms demyelinating polyneuropathy (CIDP or GBS) 5, 6, 7
• Monitor closely for progression because CIDP can initially present like GBS but requires different long-term management with corticosteroids and immunosuppressants 5, 7
• Symptoms lasting >8 weeks favor CIDP over GBS 5, 7

If Spinal Infection Suspected:

• Obtain blood cultures before antibiotics unless patient is septic 1
• Consider image-guided aspiration biopsy of vertebral lesions if MRI shows osteomyelitis or discitis 1
• Start empiric broad-spectrum antibiotics covering Staphylococcus aureus (including MRSA) and gram-negatives if clinical suspicion high 1
• Urgent neurosurgical consultation if progressive neurologic deficits, spinal instability, or large epidural abscess 1

Critical Pitfalls to Avoid

• Do not assume elevated inflammatory markers alone indicate treatment failure or infection in patients without progressive symptoms, as ESR/CRP can remain elevated for months despite clinical improvement 1
• Do not delay corticosteroids if true muscle weakness is present because myositis can rapidly progress to respiratory failure and death 1, 2
• Do not miss cardiac involvement by failing to check troponin and ECG, as myocarditis dramatically changes prognosis and management 1, 2
• Do not confuse myalgia (pain without weakness) with myositis (true weakness), as the former does not require corticosteroids 1, 2
• Do not assume all tingling is benign neuropathy when back pain and elevated inflammatory markers are present, as spinal epidural abscess can cause irreversible paralysis if missed 1

Disposition

Admit to hospital immediately for this workup given the combination of widespread neurologic symptoms, back involvement, and elevated inflammatory markers suggesting potentially life-threatening conditions (myositis with myocarditis, spinal epidural abscess, or rapidly progressive polyneuropathy) 1, 2, 8