What are the symptoms of lidocaine poisoning?

Lidocaine toxicity is mostly caused by excessive dosage or abnormal metabolism, with symptoms primarily involving the nervous system, cardiovascular system, digestive system, respiratory system, and local tissue reactions. A detailed analysis is as follows:

1. Neurological abnormalities: Early symptoms commonly include dizziness, tinnitus, blurred vision, along with numbness of the mouth and tongue and reduced sensation. As toxicity progresses, patients may develop restlessness, muscle tremors, and in severe cases, confusion, seizures, or even coma. Some patients may also exhibit slurred speech and ataxia.

2. Cardiovascular reactions: These may include bradycardia or arrhythmias such as ventricular premature beats and ventricular tachycardia. Some patients experience palpitations and chest tightness. In severe poisoning, vasodilation leads to hypotension, pallor, and cold, clammy extremities. Patients with pre-existing heart disease are at higher risk and may develop heart failure.

3. Digestive system symptoms: These are often mild and appear early, including nausea and vomiting, with vomitus typically consisting of gastric contents. Some patients may also have abdominal pain and loss of appetite. These symptoms are related to lidocaine's irritation of the gastrointestinal mucosa and its effects on the central nervous system, and usually subside as toxicity resolves.

4. Respiratory manifestations: Early signs include increased respiratory rate and shallow, rapid breathing. As toxicity progresses, respiratory center depression occurs, leading to slowed breathing and difficulty breathing. In severe cases, respiratory rhythm becomes irregular, potentially resulting in respiratory arrest. If aspiration occurs, it may lead to aspiration pneumonia, further worsening respiratory impairment.

5. Local tissue reactions: At the injection site, redness, swelling, and pain may occur. If the drug leaks out, it can cause local skin pallor, numbness, and even tissue necrosis. Some patients may develop localized allergic reactions, such as rash and itching, which are related to drug irritation or individual hypersensitivity.

Lidocaine must be used strictly according to medical instructions. Allergy history should be clarified before administration, dosage carefully controlled during injection, and vital signs closely monitored. In daily settings, the medication should be stored out of reach of children to prevent accidental ingestion. Standardized medication procedures should be followed during medical procedures to reduce the risk of toxicity.