Overview
Disease caused by parasitization of the lymphatic system by the filarial worms Bancroftia, Malayan and Timorese filarial worms may include fever, elephantiasis, swelling and pain in the groin and perineum caused by infection by Bancroftia, Malayan and Timorese filarial worms Treatment includes pathogenic treatment, symptomatic treatment, etc.
Definition
Lymphatic filariasis is a disease caused by parasites of the filarial worms Borrelia bancrofti, Filaria malayi, and Filaria timorensis in lymphatic tissue.
In the early stages, the main manifestations are lymphangitis and lymphadenitis, and in the later stages, lymphatic obstruction.
Filaria bancrofti readily affects the lymphatic vessels and lymph nodes of the genitourinary system, whereas neither Filaria malayi nor Filaria timor invades the genitourinary organs.
Morbidity
As of 2015, lymphatic filariasis is endemic in 58 countries and territories globally, with a total of 120 million people infected with lymphatic filariasis, 90% of whom have Bancroftian filariasis. There are an estimated 1.23 billion people at risk globally.
Since the 1970s, China has strengthened the prevention and treatment of filariasis, adopting ethamizine to reduce the infectiousness of the infectious agent as the leading prevention and treatment countermeasure, followed by systematic surveillance, and achieved the national elimination of lymphatic filariasis in 2006, which was confirmed by the World Health Organization (WHO).
Causes
Causes
Lymphatic filariasis is caused by filarial worms such as Filaria bancrofti, Filaria malayi and Filaria timorensis, and the basic conditions leading to epidemics are threefold.
Source of infection
Patients with microfilariae in their blood and asymptomatic carriers are the main sources of infection.
Animals already infected with Malay and Bancroftian filarial worms are also sources of infection, including monkeys and cats.
Transmission
Lymphatic filariasis is transmitted through mosquito bites. Vector mosquitoes of lymphatic filariasis include Anopheles, Aedes and Culex.
Susceptible Population
The population is generally susceptible, but males are the most common.
Symptoms
Main symptoms
Incubation period (pre-microfilarial hemorrhagic stage)
The incubation period usually lasts for about six months, from the time the infective larvae invade the body until microfilariae are found in the blood.
There are mostly no obvious symptoms in this period. Some patients may have urticaria, mild inguinal lymph node swelling and pain or spermatic cord swelling and pain, and short-term fever.
Microfilaria hemorrhagic stage
Microfilariae appear in the blood after the incubation period, and the number gradually increases until it stabilizes.
Usually there is only fever and inflammation of the lymphatic system, and some patients may not have any symptoms.
Untreated, this stage can last up to about 10 years or even for life.
Acute inflammatory stage
Mainly manifested as acute inflammation of lymphatic tissues, characterized by periodicity, every 2 to 4 weeks or every few weeks, sometimes showing irregular attacks, the cause of the attack is closely related to exercise and exertion, and is more common in summer.
Acute lymphangitis and lymphadenitis
Acute lymphangitis and lymphadenitis are the main clinical manifestations in the acute stage, mostly occurring in the lower limbs.
Common symptoms include high fever (39~40℃), local lymph node swelling and pain, lymphatic vessels swelling and pressure pain, dermatitis like dengue (flaky edematous erythema on the skin, discoloration and pain when pressed).
Spermatitis, epididymitis, orchitis
Seen in Bancroftian filariasis.
There may be recurrent fever; scrotal pain on one side, which may spread from the groin down into the scrotum and radiate to the inner thighs.
There may be enlargement and tenderness of the testes and epididymis; one or more nodules on the spermatic cord with marked tenderness.
Filarial Fever
Caused by deep lymphangitis and lymphadenitis.
Periodic fever, body temperature can be up to 40℃, accompanied by chills.
Some patients only have low-grade fever and do not have the clinical manifestations of localized acute lymphangitis and lymphadenitis.
Pulmonary eosinophilic infiltrates
It is caused by microfilariae parasitizing in lung tissues, and the organism is highly responsive to the microfilariae migrating in the lungs.
Common symptoms include chills, fever, cough, asthma, dyspnea, etc. Some patients may have urticaria and angioedema.
Chronic inflammation stage
Due to the recurrent inflammation, the lymphatic vessels proliferate to form granulomas and fibrous tissues eventually causing lymphatic obstruction and producing the following symptoms.
Enlarged lymph nodes with lymphatic varices
Enlarged lymph nodes in the groin and centripetal lymphatic varices around them often form masses.
In Bancroft’s filariasis varicocele of the spermatic cord and lymphatic obstruction common symptoms are scrotal, testicular, syringomyelia, and lymphatic effusion.
Celiac disease
A common late symptom of Bancroftian filariasis with an incidence of about 2%.
Mostly intermittent episodes, in severe cases, they are persistent.
Lymphatic ascites
Celiac ascites and celiac diarrhea are both rare in patients with Bancroftian filariasis.
Elephantiasis
The most common late stage symptom.
Elephantiasis is most common in the lower extremities, followed by the scrotum and upper extremities. Weevils of the genital organs are seen only in Bancroftian filariasis.
The elephantiasis presents as a depressed, firm type of edema with thickening and deepening of skin folds and mossy, warty nodules, which are susceptible to secondary bacterial infections and the formation of chronic ulcers.
Breast filarial nodule
Less common.
It is caused by filarial parasites in the breast tissue or surrounding lymphatic vessels.
Common symptoms include localized lumps that are slightly hard, ill-defined, inactive, and thickened skin.
Filarial pericarditis
Common symptoms include dyspnea, precordial pain, fever, and malaise.
Complications
Secondary bacterial infection
Mostly seen in people with long-term application of immunosuppressants, people with combined chronic diseases, etc.
May have fever, chills, chills and other symptoms.
Consultation
Department
Department of Infectious Diseases
If symptoms such as fever, pain in the groin and perineum, swelling, thickening and thickening of the skin occur, it is recommended to consult a doctor promptly.
Preparation for medical treatment
Consultation: Registration, Preparation of documents, Frequently Asked Questions
Tips for the doctor
Wear loose-fitting clothes for easy examination.
Record your body temperature for the doctor’s reference.
Preparation Checklist
Symptom list
Pay particular attention to the time of onset of symptoms, special manifestations, etc.
Is there fever? What is the highest temperature?
Is there any redness, swelling, thickening of the skin?
Is there swelling and pain in the groin and perineum?
Is there milky white urine?
How often do the above symptoms occur?
What aggravates or relieves the above symptoms?
List of medical history
Is there a history of traveling in a filariasis-endemic area?
Is there a history of wilderness activities, camping?
Any history of mosquito bites?
Checklist
Test results in the last six months, which can be brought to the doctor’s office
Laboratory tests: blood routine, urine routine, blood biochemistry, etc.
Medication list
Medication used in the last 3 months, if available, bring along the box or package for medical consultation
Pathogenic therapeutic drugs: etanercept, furazin, levamisole, ivermectin, etc.
Antipyretic and analgesic medications: aspirin, acetaminophen, ibuprofen extended-release capsules, etc.
Diagnosis
Diagnosis is based on
Medical history
History of traveling in a filariasis endemic area.
History of field work, activities, camping.
History of mosquito bites.
Clinical manifestations
Symptoms
There may be periodic fever, thickening and thickening of the skin, swelling and pain in the groin and perineum.
Signs
There may be elephantiasis, mostly in the lower limbs, followed by the scrotum and upper limbs, which is depressed firm edema, and there may be deepening of skin wrinkles, mossy and warty nodules, and chronic ulcers may be formed after secondary bacterial infection.
In filarial pericarditis, there may be distant heart sounds, enlarged heart boundaries, and sometimes pericardial friction sounds may be heard.
Laboratory Tests
Blood tests
Early in the course of the disease, there may be an increase in the total number of white blood cells, up to (10-20) × 109 / L, eosinophils increased significantly.
Neutrophilia is increased in those with secondary bacterial infection.
Urine routine
Check for celiac disease and celiac hematuria.
When ether is added to celiac disease, the fat is dissolved and the urine becomes clear.
Pathologic examination
Mostly check for microfilariae in the peripheral blood. Finding microfilariae in the blood is a diagnostic method for early filariasis. Microfilariae can also be examined in specimens such as syringomyelia, lymphatic fluid, celiac urine and celiac ascites.
Fresh blood film method
Earlobe blood is taken for examination, which is a simple method, but the positive detection rate is low.
Thick blood film method
Three large drops of earlobe blood are placed on a clean slide to make a thick blood film of uniform thickness, which is dried, hemolysed and stained for microscopic examination.
Centrifugal concentration method
After hemolysis, centrifugation and sedimentation, microfilariae can be found in the sediment, which can help to confirm the diagnosis of the disease.
Membrane filtration method
The diagnosis of the disease can be confirmed if the blood, after being filtered through a membrane, is stained positively with magenta or borate plus blue or hematoxylin.
The detection rate and number of microfilariae are higher than that of the thick-slice method and the concentration method, which is of great significance for epidemiological examination and assessment of prevention and treatment effects.
Biopsy
Biopsy of subcutaneous nodules, superficial lymph nodes, epididymal nodules, etc., to find adult worms and analyze their pathological changes.
Immunological examination
Including intradermal test, indirect immunofluorescence antibody test, complement binding test, etc. The specificity is not high.
Lymphangiography
Often shows dilatation of the incoming lymphatic vessels and narrowing of the outgoing lymphatic vessels, as well as parenchymal defects in the lymph nodes.
Molecular biology examination
DNA hybridization test, PCR test and other techniques can be used for the diagnosis of filariasis.
Differential diagnosis
Bacterial lymphangitis
Similarities: Both can present with lymph node pain and tenderness, and enlarged lymph nodes.
Differences: Bacterial lymphadenitis is caused by bacterial infection, and blood cultures can be performed to look for pathogens. Lymphatic filariasis is a disease caused by the parasitization of lymphoid tissues by filarial worms such as Bancroftia, Malayan filarial worms and Timorese filarial worms.
Tuberculosis of the epididymis
Similarities: Epididymal tuberculosis and lymphatic filariasis can both be characterized by swelling and tenderness of the epididymis.
Differences
Epididymal tuberculosis is caused by Mycobacterium tuberculosis. Symptoms of tuberculosis toxicity, such as night sweats, afternoon low-grade fever, and malaise, may be present, and Mycobacterium tuberculosis may be detected.
Epididymitis due to lymphatic filariasis is caused by filarial worms and often presents with symptoms of chills and high fever.
Treatment
Treatment purpose: to relieve the patient’s symptoms, eliminate pathogens, and reduce the development of complications.
Treatment principle: timely diagnosis, early treatment, pathogenic treatment, supplemented by symptomatic treatment.
Pathogen treatment
Ethamizine
Indications: It is the drug of choice for the treatment of lymphatic filariasis, which can rapidly remove microfilariae from the blood, and can also kill adult filarial worms when used in larger doses or for a longer period of time.
Adverse reactions: nausea, vomiting, chills, fever, itching of the skin may occur during treatment.
Precautions: Those with active tuberculosis, severe heart disease, kidney disease, liver disease and acute infectious diseases, as well as pregnant women under 3 months, over 8 months and menstruating women should withhold treatment. Children should be heralded for roundworms to prevent the occurrence of roundworm acute abdomen.
Furazinone
Indications: For patients with Bancroftian and Malassezia infections, able to remove microfilariae as well as adult worms from the blood.
Adverse reactions: nausea, vomiting, chills, fever, itching of the skin may occur.
Levamisole
Kills both adult worms and microfilariae.
It is now used sparingly because of the high recurrence rate.
Other
Other drugs that kill the pathogen include ivermectin, doxycycline, albendazole, etc.
Symptomatic treatment
Lymphangitis, lymphadenitis, spermatorrhea, epididymitis, orchitis.
Most of them are self-limiting and can be treated with oral antipyretic and analgesic drugs such as pau d’arco, aspirin and prednisone.
Additional antibacterial drugs are needed for secondary bacterial infections.
Lymphedema, elephantiasis
Softening of tissues: electric heat binding, far-infrared rays binding, etc. can be used.
Limb compression: use elastic band or cloth bandage on the limb for compression bandaging to reduce the leg circumference, it is preferable to tie the leg on a daily basis and loosen it at night.
Drug treatment: Coumadin, which is not anticoagulant, can be given orally.
Surgical treatment: including removal of diseased tissue, reconstruction of lymphatic vessels surgery, etc.
Syringomyelia
Injections of sclerosing agent for less fluid accumulation.
If the effusion is large, testicular syringomyelia reversal is performed to reduce the lymphatic return to the spermatic cord.
Celiac disease
Rest, consume less fatty food and drink more water during the attack.
If the systemic medication is unsatisfactory, 1% to 2% silver nitrate or 12.5% sodium iodide solution can be used to do renal pelvic pressurized perfusion with some immediate effect.
Celiac disease can be eliminated or relieved by lymphatic ligation of the renal hilum or lymphovascular-venous anastomosis.
Prognosis
Cure
Early stage of the disease is generally not life-threatening, timely diagnosis, timely treatment, the general prognosis is good; late stage of the disease has a greater impact on the patient, easy to combine with the infection, when the situation is serious, it can be life-threatening, and the prognosis is generally poorer.
Harmfulness
Lymphatic filariasis can be bacterial infection in severe cases, which may be life-threatening if not treated timely and effectively.
Daily
Daily management
Dietary management
Ensure food variety, cereal-based, recommended daily intake of cereal and potato food 250~400g, more vegetables.
Ensure high quality protein intake and reduce fat intake.
Life Management
Ensure sufficient sleep time.
It is recommended to strengthen outdoor physical exercise in daily life, such as walking, brisk walking, etc., to maintain good health.
Pay attention to personal hygiene in daily life and develop good hygiene habits.
Psychological management
Patients with lymphatic filariasis may have bad moods such as irritability and anxiety, so it is necessary to strengthen communication with patients and encourage them to maintain an optimistic state of mind.
Prevention
Control of infectious sources
Census of endemic areas and good control of patients with microfilariae in blood and asymptomatic patients carrying filariasis are the main preventive measures.
Elimination of vectors
Carry out mass anti-mosquito and anti-mosquito activities in endemic areas.
Active surveillance for filariasis control
Filariasis has been successfully eliminated in China, and few new cases have been detected after the elimination, but there is still a need to actively carry out the surveillance of filariasis control.