Internal Medicine

0521779407-07 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:10

Filariasis 573

■Loa-loa: Draw blood at noon, examine in same fashion as above for

microfilariae. In light cases, microfilariae often absent.

■Identify adult worm removed from conjunctiva or SQ nodule.

➣Onchocerciasis: remove nodule and examine for adult

worms

➣Examine small punch biopsy of skin (using a scleral punch, or

scalpel to remove small shaving that includes the dermal papil-

lae) from calves and upper buttocks in African cases, and shoul-

ders and scapular areas in W. Hemisphere cases.

➣Other tests: Lymphatic filariasis: ultrasound of hydrocele or

dilated lymph channels in groin may show motile adult

worms.

➣Serology: available in some labs but not very sensitive or specific.

PCR available on research basis.

differential diagnosis

■Lymphatic filariasis: In acute attacks, streptococcal lymphangitis,

thrombophlebitis. In chronic stage, any cause of chronic edema (Mil-

roy’s disease, previous lymphatic dissection, etc.).

■Loa loa: In light cases: other causes of urticaria, arthralgias, collagen

vascular diseases

■Onchocerciasis: Almost any cause of itching and nonspecific rash.

Nodules can resemble enlarged glands, cysts, tumors.

management

What to Do First

■Assess severity of infection.

■In onchocerciasis, do ophthalmologic exam.

General Measures

■Symptomatic treatment of pruritus, edema, cellulitis, if present

specific therapy

Indications

■Treatment of light infections in any filariasis is optional. If symp-

tomatic, treatment recommended for all.

Treatment Options

■Lymphatic filariasis: diethylcarbamazine

■Ivermectin single dose (kills microfilariae only)