A diagnostic conundrum in the time of a pandemic: a subtle, isolated myelopathy.
Federica Boso1, Bruno Giometto1
1A.P.S.S. Trento; University of Trento
Objective:
NA
Background:
Anti- CV2/collapsin response-mediator protein 5 (CRMP5) antibodies are considered "high-risk" markers, frequently associating with paraneoplastic syndromes (PNS).
Design/Methods:
NA
Results:

A 44-year-old woman was recovering from a mild case of COVID-19 when she presented with a single episode of urinary retention and a subacute paraparesis with prominent sensory disturbances and girdle-like pain. Since a spinal cord MRI did not show any lesions and EMG did not detect any conduction defects, she refused further examinations and underwent empiric antimicrobial and steroid therapy, along with physical treatment. However, almost two months later she was still suffering from dysesthesia, dysuria, dyschezia and gait disturbance. A second MRI revealed multiple, asymmetric, short-segment lesions in the spinal cord, with persistent contrast-enhancement (despite the previous steroid treatment), but no brain involvement. Cerebrospinal fluid (CSF) analysis and infectious workup were unremarkable, detecting only a slight increase in CSF proteins and a mirror pattern. An extensive screening for autoimmune and paraneoplastic diseases disclosed anti-CV2/CRMP5 antibodies in the serum; however, antibody titer and confirmatory tests were not available at that time and there was no corresponding reactivity in her CSF. After 3 months the antibodies were still present, arguing for a PET scan, which was uneventful. In the meanwhile the woman was treated with IV steroids, followed by a slow oral tapering with gradual but significant improvement. Indeed, after 6 months the MRI showed a diffuse reduction of the spinal cord swelling and T2 signal change, with no contrast enhancement; her neurological exam still remains strikingly normal.

Conclusions:
This remarkable response to immunotherapy, along with the atypical clinical phenotype and radiographic findings (when compared to reported anti-CV2/CRMP-5 myelopathies), argues for an alternative diagnosis, contemplating a post-infectious etiology rather than a PNS. The case also underlines how commercial line blots should always be confirmed by alternative and more reliable techniques. 
10.1212/WNL.0000000000204016