Prolonged neurological dysfunction after ropivacaine nerve block in a patient with systemic lupus erythematosus and diabetes mellitus: a case report

Peripheral neuropathy is a recognized complication of both diabetes mellitus (DM) and systemic lupus erythematosus (SLE), potentially increasing neural vulnerability to local anesthetics. We report a 61-year-old female with a 40-year history of SLE and 20-year history of DM who developed prolonged neurological dysfunction temporally associated with ultrasound-guided femoral and popliteal sciatic nerve blocks with 150 mg (2.7 mg/kg) of 0.5% ropivacaine for toe debridement. The patient experienced a 21-day sensorimotor deficit course characterized by: complete sensory loss and grade 0 motor function below the knee initially; asynchronous sensory-motor recovery and pain hypersensitivity during rehabilitation. Electromyography on postoperative day 21 revealed chronic axonal polyneuropathy in both upper and lower extremities, with superimposed active denervation in the left lower limb. Extended neurological dysfunction markedly deviates from typical local anesthetic neurotoxicity recovery patterns. While the temporal relationship suggests possible anesthetic-related neurotoxicity superimposed on pre-existing neuropathy, other contributing factors cannot be excluded, including acute-on-chronic worsening of diabetic neuropathy, SLE-associated chronic vasculitic neuropathy, and ischemic nerve injury. This case emphasizes the importance of detailed preoperative neurological evaluations and tailored anesthetic plans for patients with complex chronic conditions and suspected advanced peripheral neuropathy.