Metal mercury poisoning is often caused by mercury vapor. Because of its high diffusivity and fat solubility, mercury vapor enters alveoli through respiratory tract and is transported to the whole body through blood circulation. Metal mercury in blood is oxidized into mercury ions after entering brain tissue, and gradually accumulates in brain tissue, which will cause damage to brain tissue when it reaches a certain amount. The other part of mercury ion is transferred to the kidney. Therefore, the clinical manifestations of chronic mercury poisoning are mainly nervous system symptoms, such as headache, dizziness, numbness and pain in limbs, muscle tremor and dyskinesia. Excitability is a special mental state of chronic mercury poisoning, which is characterized by excitability, stuttering, timidity, anxiety, anxiety, inattention, memory loss, mental depression and so on. In addition, a series of symptoms will appear in gastrointestinal tract, urinary system, skin and eyes. The symptoms of acute mercury poisoning are hepatitis, nephritis, proteinuria, hematuria and uremia. Metal mercury is rarely absorbed by the digestive tract and generally does not cause poisoning.
Methylmercury is easily absorbed by human intestine and distributed all over the body, and most of it is accumulated in liver and kidney. Methylmercury distributed in brain tissue accounts for about 15%, but brain tissue is damaged before other tissues, and the main damaged parts are cerebral cortex, cerebellum and peripheral nerves. Therefore, methylmercury poisoning is mainly a symptom of nervous system.