Neurology & Vasculitis - A Complex Convergence

Abstract

Presentation
A 61-year-old female patient developed left ulnar neuropathy and right foot drop over 3 days.

Diagnosis
Nerve conduction studies (NCS) showed left ulnar and right common peroneal neuropathy. Inflammatory markers were raised and Anti-Neutrophil Cytoplasmic Antibodies (ANCA) positive in a peri-nuclear pattern, evident by antibodies against myeloperoxidase (MPO). Bone marrow biopsy revealed an acute inflammatory response. Cerebrospinal fluid analysis and neuro-imaging were non-diagnostic. Right sural nerve biopsy inconclusive, but demonstrated mild macrophagic infiltration nearby unmyelinated axons, raising the possibility of early peripheral nerve demyelination.

Treatment
Sensory symptoms improved post-intravenous high-dose methylprednisolone. Inflammatory markers and anti-MPO antibody titres decreased after Rituximab infusion. Following a five day course of intravenous immunoglobulins (IVIG) and regular physiotherapy, right foot power and left hand motor function subjectively improved.

Discussion
Diagnosis of mononeuritis multiplex secondary to MPO-vasculitis was supported by nerve biopsy, responsiveness to immunotherapy and antibody positivity.