Lupus Vasculitis Presenting as Confluent Mononeuritis Multiplex, New Hypotheses on Its Pathogenesis and a Case Report
Author(s): Sibi Joseph1, Thozama Dubula1, Lourdes de Fátima Ibanez Valdes1, Sandisiwe Kema1, Humberto Foyaca Sibat2*
Abstract
Background: Ischaemic vasculitic neuropathy represents the most destructive peripheral nervous system complication of Systemic Lupus Erythematosus (SLE); nevertheless, simultaneous reports of visible digital gangrene alongside electrophysiologically proven axonal neuropathy affecting the same ischaemic distribution remain uncommon.
Case presentation: A 25-year-old Black woman from South Africa’s Eastern Cape with established SLE satisfying SLICC 2012 and EULAR/ ACR 2019 classification developed a rapidly progressive, wheelchairconfined axonal sensorimotor neuropathy manifesting as bilateral foot drop and dry gangrene of the left foot with spontaneous auto-amputation of one toe. Serial outpatient testing had already revealed hypocomplementemia, anaemia, and sub nephrotic proteinuria (urine protein: creatinine 0.102 g/mmol), compatible with concurrent lupus nephritis. Nerve conduction studies showed absent distal motor and sensory responses with a distinct proximal-to-distal gradient, preserved proximal upper-limb responses, and no demyelinating features incompatible with CIDP by EAN/PNS 2021 criteria. Electromyography showed active denervation. Muscle histology revealed neurogenic atrophy with normal creatine kinase and negative CD68/CD20 immunostaining, effectively excluding primary or necrotising myopathy. CSF analysis was unremarkable, and infectious screens were negative. Extended immunology demonstrated strongly positive anti-Ro (298 U/mL), a weak lupus anticoagulant not confirmed by the phospholipid-dependent step, and uniformly negative ANCA, RF, and anti-CCP. Hepatitis B and C serology were negative. Treatment included escalation of corticosteroids, prophylactic anticoagulation, and continuation of hydroxychloroquine; rituximab was advised as the preferred immunosuppressive option.
Conclusion: This report exemplifies a fulminant lupus peripheral neuropathy in which ischaemic injury to the vasa nervorum, and the digital microvasculature produced confluent mononeuritis multiplex and digital gangrene within the same territory, in association with lupus nephritis. The presence of digital ischaemia despite palpable pulses should prompt consideration of shared small-vessel disease involving peripheral nerves and digital arterioles. Early electrodiagnostic assessment and systematic antiphospholipid testing are recommended. We propose that a key role of autoantibodies is to function as serological biomarkers and several hypotheses were released.