4/8/08

Brad Weaver

SchistosomeParasitic blood fluke of trematode familyPrevalent in tropics – 200 million people affectedAcute infection - swimmer’s itch and Katayama

feverChronic infection – deposited eggs invade tissue

and get lodged in portal circulation causing inflammation and fibrosis

Two types of renal diseaseUrinary obstruction from S. haematobiumImmune complex deposition disease from other

species

S. haematobiumDirect invasion of urinary systemAcquired in North Africa, Turkey, the Middle

East, and IndiaEggs migrate from vesical venous plexus into

bladder wall and then are excreted in urineOften presents with hematuriaChronic inflammation and fibrosis of bladder

wall can cause: Hydronephrosis and calcification of urinary

tract Bladder cancer

S. mansoni and S. japonicum Acquired in tropical areas of Africa, Asia,

South America, and the CaribbeanEggs released from mesenteric venous plexus

can travel to intestine OR enter portal blood flow and get lodged in liver sinusoids

Eggs in liver sinusoids can cause:Inflammation and progressive fibrosisSecondary portal hypertension and liver failure

Glomerular diseaseImmune complex depositionAffects 10-15% with chronic infectionTwo observations

Antibodies to schistosomal antigens can be detected in glomeruli

Schistosomal antigens can be detected in glomeruli by indirect immunofluorescense

Wide variety of clinical manifestationsProteinuriaNephrotic syndromeESRD

Sobh et al. Kidney Int 1987; 31:1006.

The “liver effect”Interplay between portal

hypertension/portosystemic shunting and glomerular disease

Kupffer cells of the liver remove circulating immune complexes and Schistosome antigens

As liver disease worsens in chronic Schistosome infections, there is increased delivery of immune complexes and antigens to glomeruli

Pathology - AFRAN classificationClass I – mesangial proliferative

glomerulonephritisClass II – exudative glomerulonephritis, many

neutrophils and monocytes, associated with dual salmonella infection

Class III – MPGN, more common in non-blacks

Class IV – FSGS, more common in blacksClass V - amyloidosis

Pathology cont.AFRAN classes I and II have good prognosis

and do not progressAFRAN classes III and IV are progressive

diseases, often lead to ESRD, and are not modified by antihelminthic drugs or immunosuppressive agents (prednisone and cyclophosphamide)

Diagnosis and treatmentPeripheral eosinophilia present in up to 2/3 of

those infectedEgg detection by microscopy

Most common method of diagnosis of Schistosomal infection

Stool O&P for all species except S. haematobium (urine micro)

Maximal egg excretion occurs between 10am and 2pm

Other tests available, lack standardization: ELISA, PCR

Treatment: praziquantel (Biltricide) 600mg tid x 1 day