2 English reference bancroftosis
3 disease classification infection department
4 disease overview bancroftian filariasis is a chronic parasitic disease caused by bancroftian filariasis parasitic in human lymphatic system, which is spread by mosquitoes. The early clinical manifestations were lymphangitis and lymphadenitis, and the late stage was elephantiasis caused by lymphatic obstruction.
1, source of infection? Only people infected with deep microfilaremia are the only source of infection (including patients and asymptomatic carriers), and no storage host has been found in nature.
2. What is the route of transmission? The medium of transmission is mosquitoes. Culex pipiens pallens is mainly distributed in the north of latitude 32 in China, and Culex pipiens fatigued is mainly distributed in the south.
3. Susceptible people are easily influenced by men, women and children. Summer and autumn are suitable for mosquito reproduction and microfilaria development in mosquitoes, so the annual incidence rate is 5- 1 1. People infected with filariasis only produce one level of immunity, so they can be infected repeatedly.
Description of the disease Bancroftian filariasis is a chronic parasitic disease caused by Bancroftian filariasis parasitic in human lymphatic system, which is spread by mosquitoes. The early clinical manifestations were lymphangitis and lymphadenitis, and the late stage was elephantiasis caused by lymphatic obstruction.
The incubation period of symptoms and signs ranges from 4 months to 1 year. After infection, half of them are asymptomatic, and microfilaria in blood is called "asymptomatic infection".
(1) Early stage (inflammatory pathological stage of lymphoid tissue)
1, acute lymphadenitis and lymphangitis? It mostly occurs in the lower limbs, characterized by swelling and pain of inguinal and abdominal lymph nodes, and then lymphangitis in the inner thigh spreads from top to bottom, which is called "retrograde lymphangitis". When inflammation spreads to capillaries in batches, local redness and tenderness appear, commonly known as "filariasis". Lymphadenitis and lymphangitis often occur periodically, mostly after fatigue, especially in summer and autumn with high fever (38℃-39℃). In addition, there are general symptoms such as fatigue, loss of appetite, muscle joint pain, limb pain and headache.
2. Filariasis fever? Chills and high fever suddenly appear periodically, and subside after 2-3 days. Some have only a low fever, not chills. There is no lymphadenitis or lymphangitis locally, sometimes accompanied. Filariasis may be caused by deep lymphadenitis or lymphangitis. In the endemic area of Bancroftian filariasis, filariasis fever attacks are very common.
3, seminal vesiculitis, epididymitis and orchitis? It is characterized by scrotal pain, and the fever agent spreads downward from groin and radiates to the inner thigh. Local examination showed that testis and epididymis were swollen and tender, and one or more nodular masses on seminal vesicle had obvious tenderness, which disappeared spontaneously after a few days, and the masses became smaller and harder. Repeated attacks can lead to the gradual enlargement of the mass.
4. Pulmonary eosinophilic infiltration syndrome? Also known as "filarial eosinophilia", it is characterized by chills, fever, cough, asthma and lymphadenopathy. There is migratory infiltration in the lung, increased bronchial vascular texture, extensive miliary mottled shadows on chest film, eosinophils and Xia Lei crystals in sputum. Eosinophils in peripheral blood increased, accounting for 20%-80% of the total number of white blood cells. Microfilaria can often be found in the blood.
(2) Advanced stage (stage of lymphatic obstructive disease)? It is a manifestation caused by the proliferation and obstruction of the lymphatic system, and inflammation still occurs repeatedly, so in most cases, inflammatory and obstructive lesions overlap.
1, lymphadenopathy and lymphangiopathy? Recurrent lymphadenitis and tortuous sinus in lymph nodes are the factors leading to lymphadenopathy. The swollen lymph nodes and their surrounding centripetal varicose veins form a mass, which is like a sponge cyst on palpation, with a sense of hard nucleus inside. Lymphatic fluid can be obtained by puncture, and microfilaria can sometimes be found. Lymph node enlargement is more common in groin. Lymphatic varicose veins are common in groin, spermatic cord, scrotum and inner thigh. Nowadays, varicocele often adhere to each other to form a cord shape, which is not easy to distinguish from varicocele, and the two coexist.
2, hydrocele? Most of them are asymptomatic, and those with more water accumulation have increased scrotal volume, disappeared wrinkles, no pain when falling to the ground, and positive light transmission test. The exudate can be grass yellow lymph or milky white chyle, and microfilaria can be seen in the exudate precipitation.
3. chyluria? One of the main clinical manifestations. Lymphatic obstruction causes lymphatic reflux of intestinal trunk lymphatic vessels and enters the urinary tract to form chyluria. The mixture of lymphatic fistula and bleeding is called chyluria. It often appears suddenly, but it can be asymptomatic before the attack, and it also has chills, fever, pain in the waist, pelvis and groin, and then chyluria. It usually lasts for several days or weeks after onset, but it can be induced again after fatigue or greasy eating. If mixed with blood, urine is milky white and pink. After standing, it is divided into three layers: the upper layer is fat, the middle layer is clear, and the lower layer is pink precipitate, which contains red blood cells, specific cells and lymphocytes, and sometimes microfilaria can be found.
4, elephantiasis and lymphedema? The two are often difficult to distinguish in clinic and often coexist at the same time. Lymphedema and reversible edema can disappear by themselves after lymphatic flow is improved. If lymphatic reflux cannot be restored, it will develop into elephantiasis over time. At this time, with or without sunken edema, the skin is thick, hard, not sweating and dry. In the later stage, it is excessive fibrosis, rough skin, and new folds and warty nodules appear. Due to local circulation disorder, the resistance is reduced, which is easy to cause streptococcus or other pyogenic bacteria infection and form chronic ulcers. The vast majority of elephantiasis occurs in the lower limbs, but it can quickly and seriously develop to the whole leg, and it can also cause elephantiasis of scrotum.
7 Etiology of disease 1, source of infection? Only people infected with deep microfilaremia are the only source of infection (including patients and asymptomatic carriers), and no storage host has been found in nature.
2. What is the route of transmission? The medium of transmission is mosquitoes. Culex pipiens pallens is mainly distributed in the north of latitude 32 in China, and Culex pipiens fatigued is mainly distributed in the south.
3. Susceptible people are easily influenced by men, women and children. Summer and autumn are suitable for mosquito reproduction and microfilaria development in mosquitoes, so the annual incidence rate is 5- 1 1. People infected with filariasis only produce one level of immunity, so they can be infected repeatedly.
Pathophysiology The onset and pathological changes of filariasis are mainly caused by adults, and the larvae in the infected period also play a role, which has little to do with microfilaria in the blood. The occurrence and development of the disease depends on the species of filariasis, the immune response of the body, the frequency of infection, the number of larvae entering the human body during the infection period, the parasitic parts of adults and whether there is secondary infection. In the process of larvae entering the body and developing into adults, the metabolites of larvae and adults, such as larval molting fluid, excreta in the womb of worms, and lysate of dead worms, can cause local lymphatic system tissue reactions and systemic allergic reactions, which are manifested as periodic lymphangitis, lymph node spread and filariasis fever. The late stage is the result of lymphoid histopathology and secondary bacterial infection.
At present, it is believed that immune mechanism is the main cause of the disease. Immune response is related to the damage of lymphatic system. Acute lymphangitis is considered as 1 type or type 3 allergic reaction, while filariasis group belongs to type 4 sideband reaction. In the early stage, exudative inflammation was dominant, lymph nodes were congested, lymph wall was edema, and the lumen was filled with pink protein solution and eosinophils. Then, the lymph nodes and lymphatic vessels appear odontogenic reaction. The center of odontogenic swelling is deformed adults and eosinophils, surrounded by fibrous tissue and epithelioid cells, with brave lymphocytes and plasma cells, similar to tuberculosis nodules. Due to the proliferation of lymphatic endothelial cells, the intima thickens and forms polyps or fibrous emboli in the fibrotic lumen, and finally the lymphatic vessels form fibrous cords, which is called occlusive lymphangitis. The obstruction of the lymphatic system leads to the increase of the pressure in the distal lymphatic vessels and the formation of lymphatic varicose veins. Even in the tissues, because of its high protein content, the subcutaneous tissues are thickened and hardened due to the continuous proliferation of fibrous tissues, thus forming elephantiasis. Because of the disorder of local circulation, the decline of skin resistance is easy to cause secondary bacterial infection, which makes elephantiasis more and more serious and even local ulcer.
9 Diagnostic examination Laboratory examination: In patients with early allergic reaction to filariasis, the total number of white blood cells is often10-20×109/L, mainly eosinophils, and neutrophils increase obviously when accompanied by bacterial infection.
(1) Etiological examination? Detection of microfilaria in blood and body fluids is the only reliable method to diagnose early filariasis.
1, blood microfilaria examination? The detection rate is the highest from evening 10 to 2 am the next day.
These methods are:
(1) thick blood slice method: three drops of earlobe blood were made into a thick blood slice with uniform thickness on a glass slide, dried, hemolyzed and stained for microscopic examination;
(2) Blood collection method: After earlobe, add a big drop of water on the glass slide for hemolysis and dilution, and after adding cover glass, look for microfilaria under the microscope. The microfilaria swings freely and curls back and forth, which is easy to identify. The method is simple, but the positive rate is low.
(3) Concentration method: take 2ml of anticoagulated venous blood, add 10ml for rectification hemolysis, shake well, centrifuge for precipitation, and take the precipitation objective for examination. This method has a high positive rate;
(4) Daytime induction: After taking 100mg pyrimethamine orally, the peripheral blood was collected at 15, 30 and 60 minutes respectively for microfilaria examination, and the detection rate was low;
(5) Membrane filtration method: 2ml of anticoagulated venous blood was filtered by a nuclear pore with a diameter of 3um, then the membrane was uncovered, stained with hot hematoxylin for 5 minutes, and then examined microscopically. The detection rate and microfilaria detection rate of this method are higher than those of thick blood slice method and concentration method.
2. Examination of microfilaria in various body fluids? Microfilariasis can be detected in hydrocele, lymph, chyluria, chylous ascites, chylothorax, pericardial effusion and bone marrow.
(2) Immunological examination
1, in-batch test? 0.05ml of canine filariasis antigen was injected into the subject's pencil, and after 15 minutes, the papules with diameter greater than > 0.9cm were positive. The test has high sensitivity and specificity, and the coincidence rate with the detection of microfilaria in blood is 86.2%-94. 1%.
2. Indirect fluorescent antibody test? In China, adult bovine filariasis was used as antigen, and the antibody in patients' serum was detected by indirect fluorescent antibody method. The positive rate was 85%-99.2%. This method has strong specificity and high sensitivity, which is suitable for epidemiological investigation and can reflect the prevention and control effect.
3. Enzyme-linked immunosorbent assay? This method has high sensitivity, strong specificity and simple operation, and is an ideal auxiliary diagnosis method for this disease.
4. Detection of circulating antigen? It has high sensitivity for microfilaria positive patients and is a specific diagnostic method, but it has poor sensitivity for microfilaria negative patients. Detection of circulating antigen with monoclonal antibody can be used as a detection method to evaluate the efficacy of anti-filariasis drugs.
(3) molecular biological examination? DNA hybridization test and PCR can be used to detect microfilaremia, especially for people who need to identify the species of microfilaria in their blood. Diagnosis? According to the life history of epidemic areas, clinical symptoms such as lymphadenitis, lymphangitis, chyluria, spermatic cord inflammation, elephantiasis, etc. occur repeatedly, and the possibility of filariasis should be considered. When microfilaria is found in peripheral blood and body fluids, the diagnosis can be confirmed. If filariasis is suspected, but microfilaria is not detected, a large dose of ethambutol (marine bacteria) can be used for therapeutic diagnosis. If fever, lymphatic system reaction and lymph node nodules appear, the diagnosis can be established. Acute lymphangitis and lymphadenitis should be distinguished from bacteria. The swelling caused by advanced inguinal lymphadenopathy is different from inguinal hernia. Spermatogonitis and epididymitis should be differentiated from epididymal tuberculosis. Eccentric urine is common in filariasis, but it is occasionally seen in tuberculosis, tumor, echinococcosis and other factors, which causes extensive damage to the retroperitoneal lymphatic system and blocks lymphatic pathways.
10 treatment scheme (I) pathogen treatment
Ethazine is the first choice drug, which can kill microfilaria and adults, and has a serious reaction after taking it. To cure filariasis, it must be treated repeatedly within a few years. Adults can take ethambutol 0.6g/d in three times for 7 days, with a total dose of 4.2g；; Patients with a lot of microfilaria in their blood and good development can take 1.5g every afternoon for 2 days, or take 0.75g twice a day for 2 days, or take 1.0g every afternoon for 3 days, with a total dose of 3.0g; or they can take a small dose for a long course of treatment once a week, with a total dose of 0.5g for 7 weeks. In epidemic areas, everyone can take medicine to avoid people with low microfilaria in the blood or chronic patients from missing treatment. Adults take 6mg/kg ethambutol each time, and children take it once a week or half a month as appropriate. Adults can also take 0.5g once, * * * 12 times. Exogenous proteins released by ethazine after killing microfilaria can cause allergic reactions, such as fever, joint pain and rash. Subsequently, when the drug acts on adults, there may be lymphatic system reactions, such as lymphangitis, lymph node swelling and pain, lymphatic dilatation, lymphatic nodules and so on. Treatment of serious heart, liver and kidney diseases, active tuberculosis, acute infectious diseases, and women who are pregnant for less than 3 months or more than 8 months should be stopped or contraindicated.
(2) Symptomatic treatment
1, lymphangitis and lymphadenitis? Secondary bacterial infection should be added with delicious antipyretic and analgesic drugs or prednisone, and antibacterial drugs.
2, chyluria? During the attack, you should stay in bed, eat less fat and drink more water, and the drug treatment effect is not ideal. For those who are not cured for a long time, 20% sodium iodide or 1%-2% silver nitrate 6- 10 ml can be used for renal pelvis irrigation, which has certain effect. Renal pedicle lymphatic dissection or lymphatic bypass may have a satisfactory effect on patients with refractory chylothorax.
3, elephantiasis and lymphedema? Comprehensive treatment based on binding may be effective. Huge scrotum or elephantiasis can be reshaped, hydrocele of tunica vaginalis can be turned over by tunica vaginalis of testis, and satisfactory results can be achieved by fibrous shell operation with leg venule-lymphatic anastomosis.
1 1 prognosis and prevention 1. Early detection of patients and carriers, timely cure and taking ethambutol for all people in epidemic areas are good measures to control the source of infection.
2. Reduce and eliminate sources of infection. Eliminate mosquito-infested areas, use drugs to kill mosquitoes, strengthen personal mosquito prevention measures, and cut off the transmission route of filariasis.
3. Strengthen epidemiological monitoring in areas where filariasis has been basically eliminated. Attention should be paid to: (1) reexamination and retreatment of the original positive patients; Make up for what has not been tested in the past; (2) Strengthen mosquito vector monitoring of households with positive blood test. If mosquito infection is found, expand blood test and mosquito control to the surrounding population with infected households as the center, so as to clear the epidemic spot and prevent further spread.
12 epidemiology filariasis is distributed all over the world and is prevalent in aurora. Filariasis is prevalent in southern China 16 provinces, autonomous regions and municipalities directly under the Central Government (including Taiwan Province Province), from Dongling, Shandong Province to Sanya, Hainan Province to the east coast and Ya 'an City, Sichuan Province to the west. It once ranked first in the world, threatening the health of hundreds of millions of people. After more than 40 years of efforts, 5/6 filariasis patients in China have been cured. Bancroftian filariasis accounts for 2/3 of the total number of filariasis patients in China, distributed in 14 counties, cities and autonomous regions, mostly in the north of the Yangtze River.
13 especially suggests that filariasis is one of the five major parasitic diseases in China. Men, women and children can be infected. The highest infection rate of microfilaria in epidemic areas is 2 1 ~ 30 years old. Bancroftian filariasis is worldwide, mainly prevalent in tropical and subtropical regions. Malayan filariasis is confined to Asia and mainly prevalent in Southeast Asia. Filariasis is prevalent in 16 provinces, municipalities and autonomous regions in central and southern China, including Shandong, Henan, Anhui, Jiangsu, Shanghai, Zhejiang, Jiangxi, Fujian, Guangdong, Guangxi, Hainan, Hunan, Hubei, Guizhou, Sichuan and Taiwan Province provinces.
The disease may be related to the host's physiological condition, living habits, especially sleeping habits; It is also related to the unique biological rhythm of microfilaria, which is influenced by and synchronized with the circadian rhythm of the host. Filariasis invades the human body during the infection period, develops into an adult and produces microfilaria, which usually takes about 8 ~ 12 months. Microfilaria can survive for 2 ~ 3 months in human body, and adults can survive for about 3 years.
Bancroftian filariasis related drugs, such as ethazine citrate tablets and nodules. The reaction of patients with filariasis malayi is often heavier than that of patients with filariasis bancrofti, and the reaction of patients with more microfilaria in blood is also heavier. filariasis ...
Pyrimethamine citrate tablets