Internal Medicine

0521779407-19 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:21

Schistosomiasis 1325

China, Philippines, Indonesia.S mekongiis variant ofS japoni-

cumfound in Mekong Delta.

➣Exposure: skin exposure to fresh water contaminated with cer-

cariae through swimming, wading, rafting. Drinking water not

established as mode of infection.

Signs & Symptoms

■Dermal phase: penetration of cercariae causes an allergic dermati-

tis, called “swimmer’s itch”, at areas of exposed skin. Also seen with

exposure to non-human (usually bird) schistosomes. Reaction to first

exposure is mild, more severe to second.

■Katayama fever: seen in heavy infections 5–7 weeks after expo-

sure, after pulmonary phase but before eggs seen. Fever, chills, nau-

sea, vomiting, diarrhea, abdominal pain, urticaria, cough, headache

may be present in varying degrees. Signs include fever, tachycardia,

urticaria, hepatosplenomegaly, lymphadenopathy, eosinophilia,

elevated IgE.

■Chronic phase: InS hematobiumthere is microscopic or gross

hematuria, sometimes urgency, and in later stages symptoms due

to ureteral obstruction or secondary urinary tract infection, often

with salmonella. InS mansonithere is chronic abdominal discom-

fort or pain, low-grade diarrhea, sometimes passage of blood. InS

japonicumsymptoms are similar but may be more severe. All forms

can develop portal hypertension, resulting in hematemesis, hepato-

splenomegaly, dilated abdominal veins.

tests

■Basic tests: blood: CBC shows eosinophilia, marked in Katayama

syndrome, moderate in chronic phase. Also mild anemia. LFTs fre-

quently mildly abnormal in both stages.

■Basic tests: urine: hematuria inS hematobium.Sometimes protein-

uria.

■Specific tests: centrifuged urine collected between 10 AM and 3 PM

(when egg emergence is at maximum) showsS hematobium.Stool

O&P shows S mansoni and japonicum.

■Serology becomes positive at 2–3 months, done at CDC by FAST-

ELISA and immunoblot techniques – very sensitive and species spe-

cific.

■Other tests:S hematobium: X-rays can show urinary tract defor-

mity or obstruction.S mansoniandjaponicum: barium enema can

show polypoid changes in colon, irritability, and biopsy through