Spinal cord compression from hypertrophic nerve roots in chronic inflammatory demyelinating polyradiculoneuropathy - A case report

Abstract

Background: Spinal cord compression secondary to nerve root hypertrophy is often attributed to hereditary neuropathies. However, to avoid misdiagnosis, rare immune-mediated neuropathy such as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) should not be overlooked. This report presents a case of multilevel nerve root hypertrophy leading to significant cord compression from CIDP.

Case description: We report a 56-year-old gentleman with type two diabetes mellitus who presented with subacute cervical cord syndrome following a fall. Mixed upper and lower motor neuron features were noted on examination. Magnetic resonance imaging showed significant pan-spinal proximal nerve root hypertrophy, compressing the cervical spinal cord. Initial radiological opinion raised the possibility of neurofibromatosis type 1 (NF-1), but neurophysiology revealed both axonal and demyelinating changes that were etiologically non-specific. C6 root and sural nerve biopsies taken at cervical decompression displayed striking features suggestive for CIDP. Although NF-1 is the most observed condition associated with root hypertrophy, other important and potentially treatable differentials need to be entertained.

Conclusion: While rare, CIDP can cause significant spinal cord compression. Furthermore, clinical manifestations of CIDP can mimic those of inherited peripheral neuropathies. Neurologists and neurosurgeons should be aware of this condition to optimize subsequent therapeutic decision-making.

Keywords: Charcot-marie-tooth disease; Chronic inflammatory demyelinating polyradiculoneuropathy; Hypertrophic neuropathy; Neurofibromatosis.

Figure 1:

Left: Lumbar nerve root involvement. (a) Sagittal T2 (off midline) shows multiple intradural nerve root nodular lesions approaching the exit foramina. (b) Axial T2 through L3 foramina shows enlarged L3 roots at the exit foramina with some thickening of the intradural cauda equina roots. (c) Axial T2 through L4 exit foramina shows thickened L4 roots extending outwards from foramina, while intradural cauda equina roots are thickened. (d) Axial T2 through S1 segment of sacrum shows lobulated L5 roots ventral to sacral alar, while S1 nerve roots at lateral recesses are enlarged. Right: Coronal STIR of the brachial plexus in sequential images from posterior to anterior. All the cervical roots are thickened and hyperintense. The first image shows the intradural components in the spinal canal.

Figure 2:

(a) Sagittal T2 shows hyperintense segmental lesions ventrolateral to the cervical cord at C4 and C5 vertebral levels compressing the cervical cord. (b) Axial T2 and (c) axial post-Gadolinium T1 at lower border of C5 vertebral level show bilateral C6 root lesions compressing the cervical cord which lies in the dorsal midline.

Figure 3:

Cervical decompression: Intraoperative finding of grossly thickened nerve root.

Figure 4:

C6 nerve root biopsy: (a) H&E (hematoxylin and eosin) stained section showing endoneurial edema and a minifascicular architecture (in longitudinal and transverse profile) due to Schwann cell proliferation militating against a neoplastic or infectious process. (b) Semi-thin resin section (toluidine blue stained) showing a marked reduction in the density of large myelinated fibers and a prominent edematous stroma. The pathology is further characterized by thinly myelinated fibers surrounded by multi-layered sheaths of Schwann cells, which all favor a demyelinating process. (c) CD3 immunostaining for T lymphocytes showed prominent focal endoneurial lymphocytic activity. (d) CD68 immunostaining highlighted phagocytic activity co-localized to the cords of Schwann cells. Sural nerve biopsy: (e) Semi-thin resin section (toluidine blue stained) showing striking loss of large myelinated fibers, endoneurial edema and concentric Schwann cell proliferation. (f) CD3 immunostaining again showing a focal endoneurial inflammatory infiltrate of T-lymphocytes.