What is the appropriate management for a patient presenting with paraparesis, considering potential causes such as spinal cord injury or underlying neurological conditions?

Management of Paraparesis

Emergent MRI of the spine without and with IV contrast is the critical first step for any patient presenting with paraparesis to identify extrinsic spinal cord compression, which requires urgent surgical decompression if present. 1

Immediate Diagnostic Priorities

Imaging

• MRI spine is the gold standard imaging modality due to superior soft-tissue resolution and multiplanar capability for evaluating the spinal canal, cord, and surrounding structures 1
• Obtain MRI without and with IV contrast to evaluate for:
  • Extrinsic compression (most common acute cause): degenerative disease, disc herniation, epidural abscess/hematoma, tumor 1
  • Spinal cord ischemia (contrast helps exclude inflammatory/infectious causes) 1
  • Inflammatory/demyelinating lesions 1
• Include diffusion-weighted imaging when spinal cord ischemia is suspected, as it shows signal changes earlier than T2-weighted sequences 1

Clinical Assessment

• Document the temporal pattern of symptom onset - acute onset (hours to days) suggests vascular or inflammatory causes, while gradual progression (weeks to months) indicates neoplastic or metabolic etiologies 2, 3
• Identify a sharp sensory level, which indicates spinal cord injury requiring emergent imaging 3
• Assess for bladder/bowel dysfunction suggesting cauda equina syndrome or spinal cord compression 3
• Check for upper motor neuron signs (hyperreflexia, clonus, Babinski sign) to localize the lesion 3

Etiology-Specific Considerations

Spinal Cord Ischemia

• Occurs in 2-6% of thoracic aortic procedures and represents the most feared complication of descending thoracic aortic repairs 2
• Risk factors include emergency surgery, dissection, extensive disease, prolonged aortic cross-clamp time, aortic rupture, patient age, prior abdominal aortic surgery, and renal dysfunction 2
• Delayed paraparesis can occur up to 27 days postoperatively and is associated with hypotension in 60% of cases 4
• Contrast enhancement is typically absent in early acute ischemia; if present, consider inflammatory or infectious etiology 1

Extrinsic Compression

• Degenerative disease (spondylotic myelopathy) is the most common cause in the acute setting, particularly in the cervical spine 1
• Epidural abscess or hematoma presents with localized back pain, fever in only one-third of abscess cases, and progressive spinal cord syndromes 3
• Vertebral fracture with retropulsion can cause myelopathy even with minor trauma or no obvious trauma history in osteoporotic or pathologic fractures 1
• Primary or metastatic tumors require surgical decompression, and combined surgery with radiotherapy shows better outcomes than radiotherapy alone for malignant spinal cord compression 2

Inflammatory/Demyelinating Causes

• Multiple sclerosis presents with multifocal paresthesias at different times, with MRI showing periventricular white matter lesions that are sharply demarcated and may enhance with gadolinium 3
• Other inflammatory conditions include neuromyelitis optica, acute disseminated encephalomyelitis, systemic lupus erythematosus, Sjögren syndrome, Behçet disease, and sarcoidosis 1

Laboratory Evaluation

Initial Workup

• Complete blood count, chemistry panel, prothrombin time, activated partial thromboplastin time for suspected vascular causes 2, 3
• CSF examination when inflammatory or infectious causes are suspected, particularly for Guillain-Barré syndrome (elevated protein without pleocytosis) 2, 3
• CSF analysis differentiates spinal cord infarction from myelitis 3

Additional Testing Based on Clinical Suspicion

• Thyroid function, vitamin B12, electrolytes (potassium, magnesium, phosphate, calcium) for metabolic causes 3
• Two-tier serology for Lyme disease if encephalomyelitis with CSF lymphocytic pleocytosis is present 3
• Screening for prothrombotic conditions in suspected cerebral venous thrombosis 2

Management Strategies

Surgical Intervention

• Surgical decompression is indicated for spinal cord compression from tumors or other mass lesions 2
• Timing is critical - do not delay imaging if there is any concern for structural compression 3

Spinal Cord Ischemia Management

• Cerebrospinal fluid drainage is a Class I recommendation for patients at high risk of spinal cord ischemic injury during thoracic aortic repair 2
• Optimize spinal cord perfusion pressure using proximal aortic pressure maintenance and distal aortic perfusion (Class IIa recommendation) 2
• Moderate systemic hypothermia for protection during open repairs (Class IIa recommendation) 2
• Prevent postoperative hypotension and continue CSF drainage for >40 hours to reduce paraparesis incidence 2
• Neurophysiological monitoring (somatosensory or motor evoked potentials) to detect spinal cord ischemia and guide treatment (Class IIb recommendation) 2

Supportive Care

• Early mobilization and rehabilitation to prevent deconditioning 2
• Management of neurogenic bladder and bowel dysfunction to prevent secondary complications 2
• Pain management, as pain is frequently reported in patients with paraparesis 2

Critical Pitfalls to Avoid

• Do not delay imaging for any patient with acute paraparesis - even if many patients have no pathology found, this is necessary to identify rare cases of epidural abscess or hematoma 3
• Avoid postoperative hypotension in patients at risk for spinal cord ischemia, as this is associated with delayed paraparesis 2, 4
• Do not assume immediate postoperative neurologic normalcy guarantees safety - delayed deficits can occur up to 27 days after thoracic aortic procedures 4
• Exercise special caution in patients younger than 10 or older than 59 years, those with progressive onset, and those with atypical presentations 3

Prognosis

• Two-thirds of patients with paraparesis following thoracic aortic surgery will recover, and about half of patients with complete paraplegia will recover to the point of walking again 2
• Intramedullary cord signal changes on MRI in spondylotic myelopathy represent prognostic factors for neurosurgical outcome 1