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Mononeuritis multiplex is a classic and distinct neuromuscular presentation in the vast majority of cases, with sequential sensorimotor deficits in the territory of discrete nerves, usually associated with significant pain and systemic features.Here we present a case of a 65-year-old man with a complex medical history of rheumatoid arthritis (RA), type 2 diabetes mellitus and chronic osteomyelitis of the distal fibula following open fracture, with chronically-discharging sinus tract. In the context of his osteomyelitis, his immunosuppressive therapies for RA had been withheld for several weeks. He initially presented to hospital with general malaise and poor mobility and was admitted at a peripheral hospital. A subacute painless left foot drop was found, along with significant median nerve sensorimotor changes in both upper limbs, and he was admitted to our hospital for further evaluation. Neurophysiology and ancillary investigations were compatible with mononeuritis multiplex, with a rheumatoid vasculitis the favoured aetiology. Therapies for RA were reinstated and additional treatment with high-dose steroids, IVIG and rituximab were added. His progress has been slow, marked by the profound axonal loss noted on his neurophysiology, but no further deficits have occurred. As his immunotherapy was slowly weaned, he underwent successful surgical treatment of his osteomyelitis and sinus tract.This case highlights the diagnostic challenges of atypical presentations, discounts the dogma of mononeuritis multiplex needing to be painful, as well as the complexity of immunosuppression in the context of active infection.