Local anesthetic systemic toxicity (LAST): This is the most direct and likely cause, as lidocaine is a local anesthetic and its toxicity can lead to systemic effects including neurological and cardiovascular symptoms.

Seizure disorders: The symptoms of lidocaine toxicity can mimic those of seizure disorders, including convulsions and altered mental status.
Cardiovascular events: Lidocaine can affect heart rhythm, and its toxicity might present similarly to other cardiac issues such as arrhythmias or myocardial infarction.
Neurological disorders: Conditions like epilepsy, meningitis, or encephalitis could present with similar neurological symptoms.

Hypoxia or anoxia: Conditions leading to inadequate oxygen supply to tissues can present with similar symptoms to lidocaine toxicity, including altered mental status and seizures, and are critical to identify and treat promptly.
Stroke or transient ischemic attack (TIA): Sudden onset of neurological deficits could be due to a vascular event, which requires immediate medical attention.
Psychiatric emergencies: Conditions like psychotic breaks or severe anxiety attacks could potentially mimic some of the neurological symptoms of lidocaine toxicity.

Malignant hyperthermia: A rare but life-threatening medical emergency that can be triggered by certain drugs, including some anesthetics, and presents with high fever, muscle rigidity, and other systemic symptoms.
Neuroleptic malignant syndrome (NMS): A rare, life-threatening disorder caused by an adverse reaction to neuroleptic or antipsychotic drugs, which can present with fever, muscle stiffness, and altered mental status.
Serotonin syndrome: A potentially life-threatening medical condition resulting from an excess of serotonin in the central nervous system, which can be caused by certain medications and presents with agitation, confusion, rapid heart rate, and changes in blood pressure.