What is the approach to managing a patient presenting with tetraparesis?

Approach to Tetraparesis

Tetraparesis requires immediate neurological localization, urgent neuroimaging, and rapid identification of life-threatening causes including spinal cord compression, brainstem stroke, Guillain-Barré syndrome, myasthenia gravis, and acute demyelinating disorders. 1

Immediate Stabilization and Assessment

• Assess airway and respiratory function immediately as cervical nerve root involvement or neuromuscular causes can lead to respiratory failure requiring intubation 2, 3
• Monitor vital signs continuously for 24-72 hours with cardiac monitoring 4
• Maintain systolic blood pressure 110-220 mmHg and diastolic 60-120 mmHg 4
• Provide supplemental oxygen if saturation <92% 4
• Position patient appropriately: head flat if no aspiration risk to maximize cerebral perfusion, or elevate 15-30 degrees if increased intracranial pressure or aspiration risk present 4

Neurological Localization

The key to diagnosis is determining the anatomical level of pathology through examination of reflexes, sensory level, and cranial nerve involvement 1:

Upper Motor Neuron Pattern (Hyperreflexia, Spasticity)

• Bilateral cerebral lesions: Look for abulia, cognitive changes, anterior cerebral artery territory involvement 5
• Brainstem lesions: Assess for cranial nerve palsies, crossed signs, respiratory pattern abnormalities 1
• Cervical spinal cord lesions: Identify sensory level, bladder/bowel dysfunction, preserved cranial nerves 1

Lower Motor Neuron Pattern (Hyporeflexia/Areflexia, Flaccidity)

• Guillain-Barré syndrome: Ascending weakness, areflexia, autonomic instability, cytoalbuminous dissociation in CSF 2
• Neuromuscular junction: Fluctuating weakness, fatigability, diplopia, bulbar symptoms suggesting myasthenia gravis 2, 6
• Muscle disorders: Proximal weakness, elevated CK, myalgias 2

Urgent Neuroimaging

Brain MRI with and without contrast is the primary imaging modality 6:

• Perform within 24 hours of symptom onset using diffusion-weighted imaging (DWI) to detect acute ischemia 4
• If MRI unavailable, obtain non-contrast CT head immediately 4
• Add cervical and thoracic spine MRI with contrast if any suggestion of spinal cord pathology (sensory level, bladder dysfunction, back pain) 1
• Include MR angiography for vascular causes 6
• Obtain orbital views if optic symptoms present 6

Critical Laboratory Evaluation

Immediate Studies

• Complete blood count, comprehensive metabolic panel, glucose 1
• Creatine kinase to assess for myositis (especially if considering immune checkpoint inhibitor toxicity) 2
• Troponin if myocarditis suspected 2
• Arterial blood gas if respiratory compromise 1

Cerebrospinal Fluid Analysis

• Perform lumbar puncture after neuroimaging if no mass effect or increased intracranial pressure 2, 1
• Assess cell count, protein, glucose for cytoalbuminous dissociation (GBS), meningitis, or demyelination 2
• Send oligoclonal bands if multiple sclerosis suspected 6
• Include Lyme and syphilis serology 2

Specialized Testing Based on Clinical Suspicion

• Acetylcholine receptor antibodies if myasthenia gravis suspected (fluctuating symptoms, diplopia, bulbar weakness) 6
• Anti-ganglioside antibodies for GBS (though often negative in immune-related GBS) 2
• MOG and aquaporin-4 antibodies if demyelinating disease suspected 6
• Interferon signature and AGS-related genes if pediatric patient with unexplained tetraparesis 7

Specific Management Based on Etiology

Immune-Related Neuromuscular Toxicity (e.g., from checkpoint inhibitors)

• Discontinue immunotherapy immediately 2
• Start methylprednisolone 2-4 mg/kg/day for mild cases, or pulse dosing 1 g/day for 5 days for severe cases 2
• Add pyridostigmine 30-600 mg daily orally if myasthenic symptoms present 2
• For life-threatening symptoms, initiate IVIG or plasma exchange urgently 2
• Mandatory neurology consultation 2

Guillain-Barré Syndrome

• Unlike idiopathic GBS, immune-related GBS responds favorably to corticosteroids (methylprednisolone 2-4 mg/kg/day) 2
• Add IVIG as additional or alternative treatment 2
• Monitor respiratory function closely for cervical nerve root involvement 2

Cerebral Causes

• If bilateral anterior cerebral artery territory infarction, consider artery-to-artery embolism source 5
• Evaluate for cerebral venous sinus thrombosis if bilateral motor signs present 8
• Screen for prothrombotic conditions 8

Spinal Cord Compression

• Emergent neurosurgical consultation if cord compression identified 9
• Consider posterior fossa decompression if Chiari malformation with syrinx 9

Monitoring for Deterioration

Watch for signs of impending respiratory failure 2, 1:

• Declining vital capacity
• Inability to cough effectively
• Bulbar weakness with aspiration risk
• Autonomic instability in GBS

Rehabilitation

• Initiate rehabilitation evaluation during acute hospitalization 4, 8
• Begin task-specific motor training with patient-initiated movement 4
• Provide physical therapy, occupational therapy, and psychological support 8
• Avoid deconditioning through appropriate exercise 8

Critical Pitfalls to Avoid

• Missing myasthenia gravis due to variable presentation - always consider if fluctuating weakness or bulbar symptoms 6
• Failing to recognize immune checkpoint inhibitor-related myasthenia/myositis/myocarditis overlap syndrome - check CK and troponin 2
• Delaying plasma exchange in life-threatening neuromuscular cases 2
• Assuming microvascular etiology without thorough workup 6
• Missing spinal cord pathology by focusing only on brain imaging 1
• Overlooking interferonopathies in pediatric patients with unexplained tetraparesis and white matter changes 7