Opportunities of exposure: synthesis of dyes and their intermediates, solvents, methylating agents and reagents
Routes of invasion: inhalation, ingestion, percutaneous absorption.
Human hazards: toxicity performance is similar to aniline, but weaker than aniline, skin contact can occur ulcers. Absorption leads to the formation of methemoglobin and cause cyanosis. Nausea, dizziness, headache, and blood effects can occur after exposure.
Diagnostic points: (refer to aniline)
(1) Methemoglobinemia The severity of its hypoxic symptoms is proportional to the amount of methemoglobin in the blood. When the concentration of methemoglobin (MHb) in the blood is 10%-15%, cyanosis has appeared on the face, lips, auricle, finger (toe) nails, but the patient may not show conscious symptoms. when MHb rises to 20%-30%, dizziness, headache, fatigue, chest tightness, tachycardia, which is already a manifestation of mild intoxication. If MHb reaches 30%-50%, cyanosis is obviously aggravated, and nausea, vomiting, numbness of limbs, unresponsiveness, drowsiness, and urinary irritation symptoms. If MHb rises to more than 50%, in addition to the appearance of generalized cyanosis, coma, urinary and fecal incontinence, respiratory distress, a variety of cardiac arrhythmias, ECG T-wave S-T-segment changes or conduction block, and in severe cases, acute circulatory failure occurs, hypoxic cerebral edema, coma, convulsions and death.
(2) Hemolytic anemia occurs 2-3 days after poisoning. Often there is weakness, cold, back pain, headache, nausea, vomiting, abdominal pain, severe fever, red blood cells and hemoglobin progressive decline. The color of hemoglobinuria also gradually deepens, and hemolytic jaundice and liver damage may occur.
(3) Kidney and bladder damage Moderate poisoning is often accompanied by bladder irritation; frequent urination, urinary urgency, urinary pain or mild hematuria. If severe hemolysis occurs can appear hemoglobinuria, oliguria, tubular urine, or even anuria. Creatinine and urea nitrogen may be elevated. However, acute renal failure is rare.
(4) Liver damage: Generally, 3-5 days after poisoning, liver pain, hepatomegaly, tenderness, jaundice, elevated total bilirubin, elevated aminotransferases, positive urobilinogen and urobilin. However, the functional abnormalities are mostly reversible and usually return to normal in 2-3 weeks.
(5) Increased urinary para-aminophenol and positive blood Hernandez microsomes help in the diagnosis.
(6) Increased urinary p-aminophenol p-aminophenol is the end product of aniline metabolism in vivo, and its increased level is closely related to the amount of aniline absorbed, so not only has diagnostic significance, but also has a predictive significance for the amount absorbed and the degree of poisoning.
Principles of treatment: Refer to the principles of treatment of aromatic amino compounds
(1) Immediately detach from the scene of poisoning, take off the poisonous clothing. Wash the skin thoroughly with soap.
(2) Treatment of methemoglobinemia ①Special effect antidote application, methylene blue is a special effect antidote for the treatment of methemoglobinemia, in small doses (1-2mg/kg) for the reducing effect, can treat methemoglobinemia. Generally, it is firstly injected intravenously with methylene blue 1-2mg/kg plus 25%-50% glucose solution 20-40 ml. Cyanosis can be significantly reduced or disappeared within 30 minutes, hypoxia symptoms are rapidly relieved, and the consciousness is turned to be clear. If the cyanosis disappears after 1-2 hours and hypoxia symptoms do not see obvious improvement, you can repeat the use of regular amount of methylene blue until the disappearance of cyanosis. ② Vitamin C has a synergistic reducing effect on methylene blue, so in the application of methylene blue at the same time, with vitamin C 3-5g added to 5% dextrose solution in 500ml of intravenous drip. ③ Oxygen therapy, should be immediately sustained high-flow oxygen. If hypoxic cerebral edema and coma have appeared, there are reports that the application of hyperbaric oxygen therapy can achieve good results. ④Prevention of cerebral edema and pulmonary edema.
(3) Prevention and treatment of hemolysis can be given to dexamethasone 20-60mg plus 10% glucose solution 20-40 ml in 2-4 times of intravenous infusion, or in 500 ml of rehydration solution in a one-time drip. And the use of Guladin (reduced glutathione) 1.2-1.6g added to 250-500ml of rehydration solution in a static drip, have a stabilizing effect on the cell membrane. Low molecular dextran 500ml can also be used IV. At the same time apply 5% sodium bicarbonate 250ml, or oral soda tablets 1-2g three times a day to alkalinize the urine. If obvious hemolysis has occurred, blood exchange and red blood cell component transfusion therapy should be given early. If acute renal failure occurs, dialysis therapy is feasible.
(4) cystitis treatment Increase water intake 2000-3000ml per day, or give 5% glucose saline and 5% dextrose solution 3000ml IV; in order to facilitate the flushing of the bladder. Alkalize the urine with 5% sodium bicarbonate 250 ml IV; procaine 15 mg 3 times a day, or 654-2 tablets 10 mg 3 times a day, to relieve the symptoms of urinary pain, urgency, and frequency. In case of hemorrhagic cystitis, hemostatic agent can be given, such as 6-aminohexanoic acid 2.0g or aminomethylenic acid 0.4g added to 10% dextrose solution for intravenous drip. Vitamin K310mg intramuscularly.
(5) Symptomatic and supportive therapies such as prevention and treatment of pelvic blood, liver preservation, prevention and treatment of infections, and maintenance of water and electricity balance.
Preventive measures: prevention of the first process reform should be carried out to strengthen the environmental health of the workshop and personal hygiene, production equipment should be strictly closed to prevent the escape of toxic banana gas and dust, and to encourage contact with the workers to drink more water in order to promote the excretion of toxic substances as quickly as possible.