Acute poisoning can occur when tetraethyl lead in the environment is inhaled through the respiratory tract, and can also occur when taken orally or absorbed in large quantities through the skin. Initially or mildly, patients first experience insomnia, nightmares, headache and dizziness. Often there is no cause for difficulty in falling asleep or waking up due to horrible nightmares. Most patients show signs of autonomic dysfunction such as loss of appetite, nausea, metallic taste in the mouth, and finger tremors. Psychiatric symptoms, agitation, convulsions or coma often appear rapidly when the disease is severe. The central nervous symptoms can be divided into: 1. Hysterical type neurosis: insomnia, nightmares, crying, laughing, shouting, singing and talking to oneself, or twitching and trembling of the limbs, and other hysterical type neurosis manifestations. The consciousness is hazy or unclear before the attack, and the attack is not accompanied by urinary incontinence or biting of the tongue, and the attack cannot be recalled after the attack. 2. Acute psychotic type: sleeplessness, restlessness, delirium, mania, persecution delusions and abundant hallucinations, and loss of orientation and self-knowledge. Tactile hallucinations are mostly persistent hairy sensations in the mouth, sometimes with skin anthroposis. Patients also have generalized tremors, convulsions or spasms, urinary incontinence; in severe cases, refusal to eat, agitation, suicide, and even death by exhaustion, high fever and coma. 3. Coma type: Very serious patients immediately fall into coma. It is common to have seizures, corkscrews, closed teeth, foaming at the mouth, and dilated pupils. The patient sweats profusely, has high fever, pulmonary edema and even respiratory and circulatory failure. In addition to the above neurological abnormalities, some patients with severe illnesses also have the “three low” signs of low body temperature, pulse rate and blood pressure, as well as autonomic dysfunction such as generalized sweating and asymmetric skin temperature of both limbs. Chronic poisoning: Chronic poisoning can occur in those who are exposed to excessive concentration of tetraethyl lead. The main manifestations are neuropathy and autonomic dysfunction. Patients often suffer from severe insomnia and intractable headaches. Patients often wake up due to nightmares, forgetfulness, dizziness, weakness, palpitations, excessive sweating, limb pain, anxious temperament, some patients have syncopal episodes, sexual dysfunction and menstrual disorders in women. Patients also have more pronounced gastrointestinal symptoms, often with epigastric pain, morning nausea, loss of appetite, and may have hyperactive eyelids, tongue muscles, finger tremors and tendon reflexes, without pathological reflexes. Some patients may present with a variable “triple low sign” with reduced basal metabolic rate, weight loss, and episodic syncope. In severe cases, toxic encephalopathy may develop. In patients with mesencephalic syndrome, there is a feeling of pressure in the precordial region, panic, excessive sweating, fluctuations in blood pressure and body temperature. Psychiatric symptoms may be present, with clinical manifestations of schizophrenia such as hallucinations and delusions.