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Progressive Spastic Paraparesis – SPS Workup — SCE Neurology MCQ

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HardMovement DisordersProgressive Spastic Paraparesis – SPS WorkupSCE Neurology

A 55-year-old woman presents with a 2-year history of progressive difficulty with tandem gait, bilateral leg spasticity, and urinary urgency. MRI brain and spine show no structural lesion. Serum B12, folate, copper, HIV, HTLV-1, syphilis, and standard autoimmune screen are all negative. CSF is normal. EMG shows no denervation. She has no family history. VLCFAs are normal. What investigation should be considered to exclude a treatable condition?

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Correct answer: B — CSF anti-GAD65 antibodies — to exclude stiff person spectrum disorder, and anti-amphiphysin antibodies

In progressive spastic paraparesis with negative standard workup, stiff person spectrum disorder (SPSD) should be considered. Anti-GAD65 antibodies (serum and CSF) and anti-amphiphysin antibodies can cause a progressive myelopathy-like syndrome. SPSD is treatable with immunotherapy (IVIg, diazepam, baclofen). Other considerations at this stage include: SPG genetic panel for hereditary spastic paraplegia (even without family history — de novo mutations occur), dopa-responsive dystonia (if there is any dystonic component), and primary lateral sclerosis (progressive UMN disease). A: Already done and normal. C: HTT causes HD, not progressive spastic paraparesis. D: Brain biopsy is premature. E: CT chest alone is insufficient.

Reference: EAN Stiff Person Syndrome Guidelines; ABN Myelopathy Guidelines