What is the differential diagnosis for a patient with a 3-day history of progressive generalized body weakness, numbness, nape (neck) pain, mild-moderate headache, and a feeling of losing consciousness?

Differential Diagnosis for Progressive Generalized Weakness, Numbness, Nape Pain, Headache, and Near-Syncope

This presentation demands immediate exclusion of life-threatening neurological and cardiovascular emergencies, particularly subarachnoid hemorrhage, meningitis, Guillain-Barré syndrome, and cardiac syncope, as the combination of progressive weakness, neck pain, headache, and near-syncope represents critical red flags that cannot be dismissed. 1, 2, 3

Immediate Life-Threatening Considerations

Subarachnoid Hemorrhage (SAH)

• Sentinel headaches occur in up to 43% of patients 2-8 weeks before major aneurysm rupture, and the combination of posterior headache with neck stiffness mandates immediate consideration even without the classic "thunderclap" presentation 2, 3
• Progressive headache over 3 days is itself a red flag suggesting potential intracranial pathology 1
• The feeling of losing consciousness may represent transient cerebral hypoperfusion from elevated intracranial pressure 3
• Obtain non-contrast head CT immediately (98-100% sensitivity in first 12 hours), followed by lumbar puncture if CT negative but clinical suspicion remains high 1, 2, 3

Meningitis/Encephalitis

• Meningitis remains possible without fever, with neck stiffness (nape pain) being a key red flag that cannot be dismissed 1
• The absence of fever does not exclude bacterial meningitis, and CSF analysis remains the principal diagnostic contributor 1
• Progressive weakness and altered consciousness (near-syncope) can indicate evolving meningeal inflammation or encephalitis 1
• If CT is negative, lumbar puncture must be performed to evaluate for infection 1

Guillain-Barré Syndrome (GBS)

• GBS should be considered in any patient with rapidly progressive bilateral weakness, particularly when accompanied by numbness and dysautonomia (near-syncope) 4
• Disease onset is typically acute or subacute, with patients reaching maximum disability within 2 weeks 4
• Dysautonomia is common and includes blood pressure or heart rate instability that can manifest as near-syncope 4
• Pain is frequently reported and can be muscular, radicular, or neuropathic, potentially explaining the nape pain 4
• Reflexes are decreased or absent in most patients at presentation 4

Cardiac Syncope

• The feeling of losing consciousness represents presyncope, defined as symptoms before syncope that could progress to complete loss of consciousness 4
• Cardiac causes of syncope carry the highest mortality risk and must be excluded 4
• Progressive generalized weakness may indicate reduced cardiac output from arrhythmia, structural heart disease, or mechanical obstruction 4
• All patients with presyncope require electrocardiography as initial evaluation 4

Secondary Differential Considerations

Vertebrobasilar Insufficiency/Posterior Circulation Stroke

• Nape pain combined with progressive weakness, numbness, and near-syncope suggests possible posterior circulation involvement 5
• Vertebrobasilar insufficiency can cause transient cerebral hypoperfusion leading to presyncope 5
• Urgent neuroimaging is required to identify structural abnormalities 5

Spinal Cord Compression

• Progressive bilateral weakness with numbness warrants consideration of cervical or upper thoracic cord compression 5
• Nape pain may indicate cervical spine pathology 5
• This is a time-sensitive emergency requiring urgent identification 5

Metabolic/Toxic Causes

• Electrolyte disturbances (hypokalemia, hypercalcemia, hypomagnesemia) can cause progressive weakness and cardiac arrhythmias leading to presyncope 6
• Hypoglycemia can present with weakness, altered consciousness, and autonomic symptoms 6
• Laboratory evaluation should assess for underlying systemic causes 5

Myasthenia Gravis/Neuromuscular Junction Disorders

• Progressive weakness with potential bulbar involvement (if nape pain reflects early neck muscle weakness) 7
• Can present with generalized weakness that worsens throughout the day 7

Critical Diagnostic Algorithm

Immediate Actions (Parallel Assessment)

1. Stabilize airway, breathing, circulation per ABCDE protocol 6
2. Obtain vital signs including orthostatic measurements (drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg suggests orthostatic hypotension) 4
3. Perform focused neurological examination looking for:
   • Meningismus/nuchal rigidity 1, 3
   • Focal neurological deficits 2, 5
   • Pupillary abnormalities 6
   • Reflex abnormalities (decreased/absent suggests GBS) 4
   • Motor strength pattern (ascending weakness suggests GBS) 4

Urgent Diagnostic Testing

1. Non-contrast head CT immediately to exclude SAH, mass lesion, or acute stroke 1, 2, 3
2. Electrocardiogram to exclude cardiac arrhythmia or ischemia 4
3. Laboratory studies: complete blood count, comprehensive metabolic panel, glucose, magnesium, calcium 5, 6
4. If CT negative but neck stiffness present: lumbar puncture for cell count, protein, glucose, gram stain, culture, and xanthochromia 1, 3

Disposition Decision

• Patients with suspected cardiac syncope, unexplained syncope after initial evaluation, or features suggesting serious conditions require specialist cardiovascular or neurological assessment 4
• Immediate neurosurgical consultation if SAH confirmed 2, 3
• Admit for monitoring and further workup if GBS suspected (intravenous immunoglobulin 0.4 g/kg daily for 5 days or plasma exchange) 4

Common Pitfalls to Avoid

• Dismissing neck stiffness without neuroimaging can lead to missed SAH, occurring in up to 12% of misdiagnosed cases 2, 3
• Assuming absence of fever rules out meningitis is incorrect, as clinical characteristics have limited diagnostic accuracy 1
• Attributing progressive weakness to benign causes without excluding GBS can delay life-saving treatment, particularly if respiratory muscle involvement develops 4
• Failing to recognize presyncope as a warning sign of impending complete syncope from cardiac causes 4
• Overlooking the progressive nature of symptoms over 3 days as a red flag for secondary pathology 1, 8