4/8/08
Brad Weaver
Schistosome
 Parasitic blood fluke of trematode family
 Prevalent in tropics – 200 million people affected
 Acute infection - swimmer’s itch and Katayama fever
 Chronic infection – deposited eggs invade tissue and
get lodged in portal circulation causing inflammation
and fibrosis
 Two types of renal disease
 Urinary obstruction from S. haematobium
 Immune complex deposition disease from other species
S. haematobium
 Direct invasion of urinary system
 Acquired in North Africa, Turkey, the Middle East, and
India
 Eggs migrate from vesical venous plexus into bladder
wall and then are excreted in urine
 Often presents with hematuria
 Chronic 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 Caribbean
 Eggs 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 fibrosis
 Secondary portal hypertension and liver failure
Glomerular disease
 Immune complex deposition
 Affects 10-15% with chronic infection
 Two observations
 Antibodies to schistosomal antigens can be detected in
glomeruli
 Schistosomal antigens can be detected in glomeruli by
indirect immunofluorescense
 Wide variety of clinical manifestations
 Proteinuria
 Nephrotic syndrome
 ESRD
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 classification
 Class I – mesangial proliferative glomerulonephritis
 Class 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 blacks
 Class V - amyloidosis
Pathology cont.
 AFRAN classes I and II have good prognosis and do
not progress
 AFRAN 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 treatment
 Peripheral eosinophilia present in up to 2/3 of those
infected
 Egg 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