Severe Post-Herpetic Lumbar Plexopathy Responds to Pulse Intravenous Methylprednisolone: A Case Report With a Side Note on its Parallel Semiology to Diabetic Radiculoplexopathy and the Vascular Invasiveness of the Varicella-Zoster Virus.

Post-herpetic lumbar plexopathy (post-herpetic segmental paresis), immune-mediated lumbar plexopathy and diabetic radiculoplexopathy (diabetic amyotrophy) have similar and seemingly parallel semiologies. The latter two conditions have an underlying microvasculitic pathological substrate that has shown potential (yet unproven) amelioration with immunodulatory therapy. These observations gave us the motivation to treat our patient with intravenous methylprednisolone for a profound proximal left leg weakness due to post-herpetic segmental paresis. In this case report, we outline in detail the clinical and electophysiolgical phenotype of this disease and we demonstrate the spectacular improvement of left leg power that had previously remained static for three months. In the discussion section, we review the vascular invasiveness of the varicella-zoster virus.