Spinal Cord Compression
The most likely diagnosis is A - Compression of Spinal Cord. The acute 3-day onset of bilateral lower extremity weakness, urinary incontinence, gait difficulty, and a clearly defined T10 sensory level without preceding infection strongly indicates a structural compressive myelopathy requiring emergency imaging and potential surgical intervention 1.
Clinical Reasoning
A defined sensory level at T10 is pathognomonic for spinal cord pathology and localizes the lesion to the thoracic spinal cord itself, not to peripheral nerves or nerve roots 1. The combination of motor dysfunction (bilateral leg weakness), sensory dysfunction (T10 level), and autonomic dysfunction (urinary incontinence) occurring acutely over 3 days represents the classic triad of spinal cord compression 1.
Why Not Guillain-Barré Syndrome (Option B)?
Guillain-Barré syndrome presents with ascending weakness starting distally in the legs and progressing upward over days to weeks, with areflexia due to peripheral nerve involvement 2. Key distinguishing features include:
- GBS causes bilateral but typically symmetrical weakness without a defined sensory level 2
- Reflexes are decreased or absent, whereas spinal cord compression typically causes hyperreflexia below the lesion 2
- GBS patients reach maximum disability within 2 weeks, but the pattern is ascending, not a fixed spinal level 2
- Bladder dysfunction in GBS is due to dysautonomia, not the acute urinary retention/incontinence seen with cord compression 2
Why Not Transverse Myelitis (Option C)?
While transverse myelitis can present similarly with bilateral weakness, sensory changes, and bladder dysfunction 3, 4, 5, several factors make it less likely:
- Transverse myelitis typically follows a viral infection or immune-mediated process 5, 6
- The patient has no history of preceding infection, which is atypical for transverse myelitis 1, 3
- Transverse myelitis symptoms typically develop over hours to days and progress to maximum severity within 10 days, but the absence of infectious prodrome makes structural compression more likely 1, 4
- Compressive myelopathy and transverse myelitis are often clinically indistinguishable, which is why imaging must be the priority 3
Why Not Cauda Equina Syndrome (Option D)?
Cauda equina syndrome affects lumbosacral nerve roots below the L1-L2 vertebral level 1. Critical distinctions include:
- A T10 sensory level is anatomically too high for cauda equina syndrome, which would cause lower motor neuron signs with areflexia 1
- Cauda equina presents with saddle anesthesia and asymmetric leg weakness, not a defined thoracic sensory level 1
Immediate Management Algorithm
Step 1: Obtain emergency MRI of the entire spine (without and with contrast) immediately to differentiate between compressive lesions and non-compressive myelopathy 1. Do not delay imaging, as spinal cord compression requires urgent surgical decompression within hours to prevent permanent neurological deficit 1.
Step 2: Urgent neurosurgical consultation upon clinical suspicion, as timing of decompression is critical for neurological recovery 2, 1. Early surgical decompression within 24 hours is associated with better functional outcomes in compressive myelopathy 1.
Step 3: Supportive care while awaiting imaging and consultation 2:
- Maintain spinal precautions
- Monitor neurological status closely for deterioration
- Bladder catheterization for urinary retention 2
- Prevent complications including deep vein thrombosis prophylaxis 2
Critical Pitfalls to Avoid
Do not attribute the presentation to a medical cause without excluding surgical compression first 1, 3. Compressive myelopathy requires emergent surgical intervention, and delayed diagnosis leads to irreversible neurological damage 1.
Do not wait for additional symptoms or laboratory results before obtaining MRI 1. The presence of a sensory level with acute bilateral weakness and bladder dysfunction mandates immediate imaging 1.
Do not assume transverse myelitis based on the acute presentation alone 3. While both conditions can be clinically indistinguishable, the absence of infectious prodrome and the need to exclude compression make imaging the absolute priority 1, 3.