Filariasis
Original Editors - Kim McMillin from Bellarmine University's Pathophysiology of Complex Patient Problems project.
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Definition/Description[edit | edit source]
Lymphatic filariasis is a disease associated with parasitic infection of one of three different nematodes: Wuchereria bancrofti, Brugia malayi, or Brugia timori. The microscopic worms enter the human body via mosquito transmission- in both children and adults- and can live up to 5-7 years in the lymphatic system. Although most people who are infected are asymptomatic, a small percentage of people will develop extreme lymphedema and multiple secondary infections as a result of years of exposure to the parasites. (CDC)
Prevalence[edit | edit source]
It is estimated that more than 120 million people in 80 countries worldwide are currently infected with one of the three nematodes. Greater than 90% of those 120 million people are infected with the Wuchereria bancrofti filaria, and the majority of the remaining ~10% are infected with the Brugia malayi filaria. Reports also suggest that more than 40 million people are significantly dibilatated and disfigured by the disease. (Lymphatic filariasis: the disease and its control. Fifth report of the WHO Expert Committee on Filariasis. World Health Organ Tech Rep Ser 1992; 821:1.)
Lymphatic filariasis is endemic is the tropic and sub-tropics of Southeast Asia, Africa, the India Subcontinent, the Pacific islands, and parts of the Caribbean and Latin America. (CDC; Ngwira BM, Jabu CH, Kanyongoloka H, et al. Lymphatic filariasis in the Karonga district of northern Malawi: a prevalence survey. Ann Trop Med Parasitol 2002; 96: 137.)
Characteristics/Clinical Presentation[edit | edit source]
The majority of people who become infected with filariasis do not show any overt clinical signs or symptoms, although they will experience irregularities in their lymphatic drainage. It is estimated that only one-third of those infected by any of the filarial nematodes show obvious clinical features of the condition. Experts have attributed the severity of symptoms as being positively correlated with extended time of exposure and accumulation of worms.
ACUTE Signs & Symptoms:
- Adenolymphangitis
- Filarial fever
- Tropical pulmonary eosinophilia
Acute adenolymphangitis: Characteristics include painful lymphadenopathy and retrograde lymphangitis that most often affect the inguinal nodes, genitalia, and lower extremities leading to extreme edema, elephantiasis, and sometimes skin breakdown and secondary infections. Flare-ups can last 4-7 days and occur up to 4 times per year depending on the severity of the lymphedema. (Pani SP, Srividya A. Clinical manifestations of bancroftian filariasis with special reference to lymphoedema grading. Indian J Med Res 1995; 102:114)
Filarial fever: Often an acute fever that occurs independently of any other signs of lymphadenopathy. Filarial fever is sometimes misdiagnosed as a manifestation of malaria and other tropical diseases because of the lack of associated symptoms.
Tropical pulmonary eosinophilia: Most commonly seen in young males and is caused by microfilariae being trapped in the lungs. The immune system exhibits a respiratory "hyperresponsiveness" to the problem, causing excessive nocturnal wheezing.
CHRONIC Signs & Symptoms:
- Lymphedema
- Renal Pathology
- Secondary infections
Lymphedema: Commonly involves vessels in the inguinal and axillary lymph nodes, affecting all four extremities. Early stage lymphedema is usually characterized by pitting edema, but more chronic stages exhibit non-pitting edema with hardening of the surrounding tissues, eventually leading to hyperpigmentation and hyperkeratosis. Chronic manifestations can also involve the breasts and male genitalia. Hydroceles (swelling of the scrotum) can be greater than 30cm in diameter, but are usually painless unless bacterial infection is present.
Renal Pathology: When renal system lymphatic are obstructed, lymph fluid can be passed into the renal pelvis. Chyluria, or lymph fluid in the urine, causes a milky appearance in the excreted urine. Hematuria and proteinuria may also be present and can eventually cause nutritional deficiencies and anemia.
Secondary infections: Bacterial and fungal infections become problematic in lymphatic filariasis due to edema-causing skin folds and skin tears.
Associated Co-morbidities[edit | edit source]
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Medications[edit | edit source]
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Diagnostic Tests/Lab Tests/Lab Values[edit | edit source]
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Etiology/Causes[edit | edit source]
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Systemic Involvement[edit | edit source]
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Medical Management (current best evidence)[edit | edit source]
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Physical Therapy Management (current best evidence)[edit | edit source]
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Alternative/Holistic Management (current best evidence)[edit | edit source]
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Differential Diagnosis[edit | edit source]
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Case Reports/ Case Studies[edit | edit source]
Barreto SG, Rodrigues J, & Pinto RGW. Filarial granuloma of the testicular tunic mimicking a testicular neoplasm: a case report. Journal of Medical Case Reports. 2008; 2(321).
Available at: http://jmedicalcasereports.com/content/2/1/321
Cengiz N, Savaş L, Uslu Y, Anarat A. Filariasis in a child from southern Turkey: a case report. Turk J Pediatr. 2006 Apr-Jun;48(2):152-4.
Available at: http://www.ncbi.nlm.nih.gov/pubmed/16848117
Kapoor AK, Puri SK, Arora A, Upreti L, Puri AS. Case report: Filariasis presenting as an intra-abdominal cyst. Indian J Radiol Imaging 2011;21:18-20.
Available at: http://www.ijri.org/text.asp?2011/21/1/18/76048
Resources
[edit | edit source]
Centers for Disease Control and Prevention: http://www.cdc.gov/parasites/lymphaticfilariasis/epi.html
Tropical Disease Research: http://www.TropIKA.net
World Health Organization: http://www.who.int/mediacentre/factsheets/fs102/en/
Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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