What are the various causes and management options for paraparesis?

Various Causes of Paraparesis

Paraparesis results from spinal cord lesions caudal to the second thoracic segment, with the most common causes being spinal tuberculosis (30%), acute transverse myelitis (20%), primary spinal cord tumors (10%), vascular disorders including spinal cord ischemia, and less commonly, inborn errors of metabolism and demyelinating diseases. 1, 2

Etiological Categories

Compressive Causes

• Spinal tuberculosis is the leading cause of non-traumatic paraparesis, particularly in endemic regions, presenting with backache (75% of cases) and progressive weakness 2
• Primary spinal cord tumors account for 10% of cases and require surgical decompression, with combined surgery and radiotherapy showing superior outcomes to radiotherapy alone for malignant compression 3, 2
• Extradural, intradural/extramedullary, and intramedullary lesions can be differentiated by MRI patterns to guide specific management 4

Vascular Causes

• Spinal cord ischemia following thoracic aortic surgery occurs in 2-6% of descending thoracic repairs and 3-10% of thoracoabdominal repairs 1, 3
• Risk factors include emergency surgery, dissection, prolonged aortic cross-clamp time, aortic rupture, advanced age, prior abdominal surgery, and renal dysfunction 3
• Cerebral venous thrombosis involving the sagittal sinus can cause bilateral motor signs including paraparesis and requires screening for prothrombotic conditions 1, 3

Inflammatory and Demyelinating Causes

• Acute transverse myelitis represents 20% of non-traumatic paraparesis cases and may require CSF examination showing elevated protein and cells 2, 3
• Multiple sclerosis can present with spastic paraparesis, with MRI showing periventricular plaques and CSF demonstrating oligoclonal bands and elevated myelin basic protein 5

Metabolic Causes

• Inborn errors of metabolism can present as isolated spastic paraparesis in adults for years before other systemic manifestations appear, making them critical to identify as they are often treatable 1, 6

Diagnostic Approach

Initial Clinical Assessment

• Document the rate of symptom onset: acute onset suggests vascular or inflammatory causes, while gradual progression suggests neoplastic or metabolic etiologies 7
• Identify accompanying symptoms: backache (75%), paresthesias (62.5%), bladder/bowel dysfunction, and sensory level help localize the lesion 2
• Assess for spasticity (present in 57.5%), hyperreflexia, clonus, and Babinski signs to confirm upper motor neuron involvement 2, 8
• Screen for exacerbating factors: constipation, urinary tract infections, and pressure ulcers can worsen existing spasticity 8

Laboratory Evaluation

• Complete blood count, chemistry panel, PT/aPTT for suspected vascular causes 3
• CSF examination when inflammatory or infectious causes are suspected, looking for elevated protein, cells, oligoclonal bands, and myelin basic protein 3, 5
• Prothrombotic screening if cerebral venous thrombosis is suspected 1, 3

Imaging Strategy

• MRI of the spine without and with contrast is the primary imaging modality, classifying findings into six patterns: extradural, intradural/extramedullary, intramedullary, intramedullary-tract specific, spinal cord atrophy, or normal-appearing cord 4
• CT myelography can delineate primary spinal cord tumors and confirm diagnosis in spinal TB, showing block in 58.5% of compressive cases 2
• Brain MRI should be obtained if multiple sclerosis is suspected, looking for periventricular plaques 5

Management Strategies

Vascular Causes (Post-Aortic Surgery)

• Cerebrospinal fluid drainage is the primary spinal cord protective strategy in high-risk patients (Class I recommendation) 3
• Maintain spinal cord perfusion pressure through proximal aortic pressure maintenance and distal aortic perfusion (Class IIa) 3
• Prevent postoperative hypotension aggressively in the ICU, and continue CSF drainage for >40 hours to reduce paraparesis incidence 1, 3
• Moderate systemic hypothermia during open repairs provides additional protection (Class IIa) 3
• Neurophysiological monitoring with somatosensory or motor evoked potentials can detect spinal cord ischemia and guide treatment (Class IIb) 3

Compressive Causes

• Surgical decompression for spinal cord compression from tumors or mass lesions, with combined surgery and radiotherapy superior to radiotherapy alone for malignant compression 3
• Anti-tuberculous therapy for spinal tuberculosis, often combined with surgical decompression in cases with neurological deficit 2

Inflammatory Causes

• Pulse steroid therapy for acute transverse myelitis and multiple sclerosis exacerbations improves outcomes 5

Spasticity Management

• Eliminate triggers first: treat constipation, urinary tract infections, and pressure ulcers 8
• Neurophysiotherapy as the foundation of spasticity management 8
• Oral medications: baclofen, tizanidine, or dantrolene for generalized spasticity 8
• Focal botulinum toxin injections for localized spasticity 8
• Intrathecal baclofen pump for severe, refractory spasticity 8

Rehabilitation and Complications Prevention

• Early mobilization to prevent deconditioning 3
• Neurogenic bladder and bowel management to prevent secondary complications 3
• Pain management as pain is frequently reported 3
• Referral to specialists: physical therapy, ophthalmology if visual symptoms, and psychological support for incomplete recovery 1

Prognosis

• Two-thirds of patients with paraparesis following spinal cord ischemia recover some function, and approximately half with complete paraplegia recover to the point of walking 1, 3

Critical Pitfalls to Avoid

• Do not miss treatable metabolic causes by limiting workup to structural and inflammatory etiologies only 6
• Do not delay CSF drainage in post-aortic surgery patients, as continued drainage >40 hours significantly reduces paraparesis incidence 1, 3
• Do not overlook cerebral venous thrombosis in patients with bilateral motor signs, as this requires anticoagulation rather than spinal-directed therapy 1, 3