Loa loa: Difference between revisions
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Loa loa
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==Background== |
==Background== |
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===Epidemiology=== |
===Epidemiology=== |
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| + | |||
| − | * |
+ | *Transmitted by ''[[Chrysops silacea]]'' and ''[[Chrysops dimidiata]]'' flies |
| + | **Day biting flies, more common in rainy season and in rain forests |
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| + | **Attracted by fires and to rubber plantations |
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| + | *Present in West and Central Africa, primarily in Equatorial Guinea, Gabon, Cameroon, Central African Republic, Congo (Brazzaville), DRC, Nigeria, Chad, Sudan, Angola, Ethiopia |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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| + | |||
| − | * |
+ | *Often asymptomatic |
| − | * |
+ | *Most common symptom is '''Calabar swellings''', a 10- to 20-cm painful, itchy subcutaneous swelling caused by migration of the adult worms |
| − | ** |
+ | **The lesions are essentially angioedema in response to the worm |
| − | * |
+ | *Worms can also migrate to the conjunctiva, where they are visible |
| − | * |
+ | *Infection can be complicated by [[Causes::hematuria]] and [[Causes::proteinuria]] |
| + | |||
| + | === Complications of Treatment === |
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| + | |||
| + | * Treatment with antiparasitics may cause an increase in symptoms such as Calabar swellings or pruritis |
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| + | * With treatment of high-level parasitemia, can cause fatal encephalopathy |
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| + | |||
| + | == Diagnosis == |
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| + | |||
| + | * Demonatration of microfilaria on Giemsa-stained blood film collected during daytime (10 am to 2 pm) |
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| + | ** Also provides quantification of microfilarial burden |
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==Management== |
==Management== |
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| + | |||
| ⚫ | |||
| + | *Not all infections require treatment |
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| + | *Before treatment |
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| ⚫ | |||
| + | **Rule out [[Onchocerca volvulus]] coinfection, as treatment with DEC can lead to blindness or exacerbation of skin disease |
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| + | *If microfilaremia <8000 MF/mL |
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| + | **First-line treatment is [[diethylcarbamazine]] 8-10 mg/kg/day po divided tid for 21 days |
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| + | ***Kills both the adult worms and microfilaria |
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| + | **After failing 2 rounds of DEC, [[albendazole]] 200 mg bid for 21 days |
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| + | *If microfilaremia ≥8000 MF/mL, either: |
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| + | **[[Albendazole]] as above to decrease levels below 8000, followed by DEC as above |
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| + | **Apheresis to decrease levels below 8000, followed by DEC as above |
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| + | *[[Levamisole]] 0.25 mg/kg p.o. once is a promising new treatment[[CiteRef::campillo2021sa]] |
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| + | *Can consider concomitant [[antihistamines]] or [[corticosteroids]] during the first week of treatment to decrease symptoms associated with treatment |
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{{DISPLAYTITLE:''Loa loa''}} |
{{DISPLAYTITLE:''Loa loa''}} |
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Latest revision as of 13:06, 27 September 2024
Background
Epidemiology
- Transmitted by Chrysops silacea and Chrysops dimidiata flies
- Day biting flies, more common in rainy season and in rain forests
- Attracted by fires and to rubber plantations
- Present in West and Central Africa, primarily in Equatorial Guinea, Gabon, Cameroon, Central African Republic, Congo (Brazzaville), DRC, Nigeria, Chad, Sudan, Angola, Ethiopia
Clinical Manifestations
- Often asymptomatic
- Most common symptom is Calabar swellings, a 10- to 20-cm painful, itchy subcutaneous swelling caused by migration of the adult worms
- The lesions are essentially angioedema in response to the worm
- Worms can also migrate to the conjunctiva, where they are visible
- Infection can be complicated by hematuria and proteinuria
Complications of Treatment
- Treatment with antiparasitics may cause an increase in symptoms such as Calabar swellings or pruritis
- With treatment of high-level parasitemia, can cause fatal encephalopathy
Diagnosis
- Demonatration of microfilaria on Giemsa-stained blood film collected during daytime (10 am to 2 pm)
- Also provides quantification of microfilarial burden
Management
- Not all infections require treatment
- Before treatment
- Must rule out high-level microfilaremia (>2500-8000 microfilariae/mL) before considering medical treatment, due to the risk of encephalopathy
- Rule out Onchocerca volvulus coinfection, as treatment with DEC can lead to blindness or exacerbation of skin disease
- If microfilaremia <8000 MF/mL
- First-line treatment is diethylcarbamazine 8-10 mg/kg/day po divided tid for 21 days
- Kills both the adult worms and microfilaria
- After failing 2 rounds of DEC, albendazole 200 mg bid for 21 days
- First-line treatment is diethylcarbamazine 8-10 mg/kg/day po divided tid for 21 days
- If microfilaremia ≥8000 MF/mL, either:
- Albendazole as above to decrease levels below 8000, followed by DEC as above
- Apheresis to decrease levels below 8000, followed by DEC as above
- Levamisole 0.25 mg/kg p.o. once is a promising new treatment1
- Can consider concomitant antihistamines or corticosteroids during the first week of treatment to decrease symptoms associated with treatment
References
- ^ Jérémy T Campillo, Paul Bikita, Marlhand Hemilembolo, Frédéric Louya, François Missamou, Sébastien D S Pion, Michel Boussinesq, CédricB Chesnais. Safety and Efficacy of Levamisole in Loiasis: A Randomized, Placebo-controlled, Double-blind Clinical Trial. Clinical Infectious Diseases. 2021;75(1):19-27. doi:10.1093/cid/ciab906.
