A Rare Presentation of Non-systemic Vasculitic Neuropathy Mimicking Guillain-Barré Syndrome: A Case Report.

Vasculitic neuropathy typically presents as a painful, asymmetrical sensory-motor polyneuropathy, more commonly demonstrating a mononeuritis multiplex. We present the case of a 63-year-old woman who experienced acute-onset flaccid weakness in all four limbs following an episode of diarrhea. Guillain-Barré syndrome (GBS) was considered, which supported acute motor axonal neuropathy (AMAN) in the nerve conduction study (NCS). On the second day of treatment with intravenous immunoglobulin (IVIG), a vasculitic-type rash appeared along with limb pain. Furthermore, the asymmetrical sensory and motor weakness did not respond well to the treatment. A positive skin biopsy, however, with a negative nerve biopsy combined with repeat NCSs demonstrating mononeuritis multiplex, confirmed the diagnosis of non-systemic vasculitic neuropathy (NSVN) based upon Brighton Case Collaboration type 3. This presentation underlines the significance of considering vasculitic neuropathy as a potential diagnosis and highlights the importance of an accurate diagnosis, as this condition can be effectively treated.