The pathogenesis of acute schistosomiasis is still unclear. At present, it is thought that it may be immune complex disease or serum disease. In the early stage of schistosomiasis infection, cercaria and migratory larvae can stimulate the host to produce antibodies, but the antibody level is low. When juvenile worms develop into mature adults and lay eggs in large quantities, a large number of egg soluble antigens released by eggs stimulate the host to produce antibodies quickly, and in the case of excess antigens, soluble antigen-antibody complexes are formed, causing vascular damage and causing disease. When new antibodies are rapidly formed and exceed the antigen content, or when granulation tissue isolation antigen is formed around the eggs, the disease can be terminated.
For a long time, antimony potassium tartrate is the main specific medicine. However, it also has some disadvantages, such as high toxicity, long course of treatment and the need for intravenous injection. In 1970s, it was found that praziquantel was highly effective, low toxic, short in course of treatment and effective by oral administration, which was a breakthrough in the history of schistosomiasis control, and now it has completely replaced antimony potassium tartrate.
[therapy]
(1) To support and treat patients with persistent high fever in acute stage, adrenocortical hormone or antipyretic can be used to relieve poisoning symptoms and cool down first. For chronic and advanced patients, we should strengthen nutrition, give high-protein diet and multivitamins, and pay attention to the treatment of anemia. When cirrhosis has portal hypertension, it is necessary to strengthen liver treatment and surgical treatment. People with other intestinal parasitic diseases should be treated with insect repellent.
(2) Pathogenic therapy
(1) Praziquantel is a pyrazine compound with colorless and odorless crystalline powder. Slightly soluble in ethanol, insoluble in water. It can kill larvae, children and adults. It is easy to be absorbed from the intestine after oral administration, and the blood concentration reaches the peak in about 5/2 hours. Liver has the highest concentration in the body, and metabolites are excreted from urine within 24 hours. At present, the drug contents of ordinary tablets and enteric-coated tablets in China are 0.2 g and 0.05g respectively. The total dose of clinical treatment for acute schistosomiasis is 1.20mg/kg for children and 1.40mg/kg for 4-6 days, 2-3 times a day, and the cure rate is 1.000%. For patients with chronic and advanced diseases, the total dose for one course of treatment is 60mg/kg for adults and 70mg/kg for children, with a dose of 1 ~ 2 days, three times a day. Side effects are rare and mild, including dizziness, fatigue, sweating and mild abdominal pain. The drug has the advantages of high efficiency, low toxicity and short course of treatment, and is an ideal anti-schistosomiasis drug at present.
(2) Niger (amoscanate): orange powder, insoluble in water. It is a broad-spectrum insect repellent, and animal tests have been effective on four kinds of schistosomiasis. It is absorbed from the small intestine after oral administration, and the highest concentration is distributed in the liver. Through bile and urine excretion, the part of bile excretion can be reabsorbed for enterohepatic circulation. Some of them can enter brain tissue through the blood-brain barrier. The total dose of treatment is 7mg/kg, and the maximum dose is not more than 350mg, which is taken in three equal parts and every night before going to bed. During the treatment, you should eat a low-fat diet and avoid smoking. It is suitable for all stages of schistosomiasis, and the long-term curative effect is 85%. 1 At the end of the year, hepatitis, chronic hepatitis, liver cirrhosis, advanced schistosomiasis with obviously decreased liver function, history of mental illness and neurosis should not be used by women during pregnancy or lactation. Use with caution in patients with organic heart disease. The side effects of drugs include dizziness, fatigue, dizziness, wandering feeling, dreaminess, anorexia, nausea, diarrhea, abdominal pain, liver pain and so on. A few have numbness of limbs, muscle tremor, nystagmus, premature beats, arrhythmia and so on. It subsided after stopping the drug for one week. A few patients may have jaundice and liver function changes. A-S-S syndrome is occasionally seen.
(3)pararosnailine is a polyphenylmethane red dye. It can inhibit acetylcholinesterase, cause endogenous acetylcholine accumulation, cause sucker paralysis, insect paralysis, folding separation and liver migration. It has good curative effect on schistosomiasis in all stages. Each tablet is 0. 1g, with a total daily dosage of 50 ~ 60mg/kg, which is taken in three times, with 20 or 28 days as a course of treatment. The long-term curative effect is more than 90%, and the side effects of the drug are dizziness, dizziness, blurred vision, fatigue, palpitation and digestive tract symptoms. In severe cases, allergic reactions such as systemic rash and agranulocytosis may occur. Use with caution in patients with liver and kidney dysfunction.
(4) Combined treatment of nitrofurazone and trichlorfon: nitrofurazone is odorless and tasteless. After oral administration, nitrofurantoin is mainly absorbed from the small intestine and enters the superior mesenteric vein and portal vein system, killing both adults and larvae of Schistosoma japonicum. Because it degrades in the upper digestive tract, it has little effect on worms parasitic in the inferior mesenteric vein and its branches, and the clinical effect is poor when used alone. Trichlorfon inhibits cholinesterase activity, causing paralysis and liver metastasis, and the combination of the two drugs has synergistic effect. The course of treatment is 10 day, and the daily dose is 60mg/kg for adults and 70mg/kg for children. The maximum daily dose for adults should not exceed 3g. Half dose was given in the first 65,438+0 ~ 2 days to reduce the reaction, and then the full dose was used for 8 days.
Trichlorfon has low toxicity and is easily hydrolyzed into dichlorvos in alkaline solution, which increases its toxic and side effects. The combination of these two drugs has a synergistic effect. On the 2nd-3rd day of treatment, put 1 suppository in rectum at a distance of 0/0 cm from anus every night, and lift the buttocks for half an hour. * * * After being used for three times, the negative rate of eggs reached 90%. Trichlorfon is injected intramuscularly every day 100 ~.
Side effects: Furpromide can cause gastrointestinal reactions such as loss of appetite, nausea, vomiting, abdominal pain, diarrhea and bloody stool. It can also cause muscle spasm and neuropsychiatric symptoms, and the above reactions can be relieved by themselves, and the treatment can be terminated in severe cases. Trichlorfon can cause dizziness, headache, insomnia, hyperhidrosis, salivation and other gastrointestinal symptoms, which can be relieved after symptomatic treatment, without affecting the continued treatment. Individual patients can cause Asperger's syndrome, which can be treated with atropine, pralidoxime and other antidotes, and the treatment of trichlorfon can be stopped. Combined therapy is prohibited for diseases such as mental history, neurosis, ulcer, nephritis and hepatitis.
Other anti-schistosomiasis drugs: oral sodium antimonate gallate (antimony -273) and intravenous potassium antimonate. It has been used less at present.