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Background and Aims Systemic toxicity from local anesthetics is a rare, yet often lethal complication. We present a case of local systemic toxicity following a femoral nerve block in a 68-year old patient who underwent a total knee arthroplasty. Our aim is to raise awareness among colleagues to identify the first signs of this condition, as well as suggest appropriate patient management.Methods The patient was a 68-year-old female (ASA II), with a patient history of hypertension, managed by a b-blocker. Pre-op clinical examination and lab tests were normal. An ultrasound-guided femoral nerve block was performed post-op for analgesia, after the patient had undergone a left total knee arthroplasty. A solution of 20 ml 0,2% ropivacaine was administered. The patient began to experience a metallic taste and tongue numbness, and appeared disorientated. Vital signs were 80/40 mmHg, 98% Sp02, 42 bpm. Systemic toxicity was suspected. One dose of 1.5 ml/kg of 20% intravenous lipid emulsion was administered, followed by continuous infusion. The patient was promptly intubated and supported with fluids and vasopressors. She was transferred to the ICU.Results The patient was extubated 48 hours later without complications.Conclusions Systemic toxicity of local anesthetics can be life-threatening, and clinical symptoms may often initially be mild. It is often believed that systemic toxicity arises when using large volumes of local anesthetics, however this case report reveals that it may present even when using appropriate volumes. Identifying symptoms quickly is key in order to prevent devastating outcomes.