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Case Study: Schistosomiasis Dr. Jennifer Coetzee CMID / Ampath.

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Presentation on theme: "Case Study: Schistosomiasis Dr. Jennifer Coetzee CMID / Ampath."— Presentation transcript:

1 Case Study: Schistosomiasis Dr. Jennifer Coetzee CMID / Ampath

2 Clinical Presentation 8 year old boy Referred to renal clinic from peripheral hospital Two year history of painless, macroscopic hematuria Urine microscopy: eggs of Schistosoma haematobium

3 Objectives Describe the life cycle of the bilharzia parasite Discuss the pathogenesis of bilharzia as a prototype of a parasitic infection Briefly describe the principles of the diagnosis and management of this infection

4 Ross A et al. N Engl J Med 2002;346:1212-1220 Life Cycle of the Schistosome Life Cycle of the Bilharzia Parasite

5 Pathophysiology and Clinical Disease Acute disease: –Cercarial dermatitis after penetration of the cercaria –Swimmers itch if cercaria from birds involved –After onset of egg laying, may develop acute reaction (Katayama fever) if never exposed before –Symptoms resolve as immune system adapts

6 Chronic Stages Eggs entrapped in host tissues secrete antigens Incite an inflammatory granulomatous response Granulomas eventually replaced by dense fibrosis obstruct blood flow Clinical symptoms vary according to species, total worm burden, patients stage of health at time of infection

7 Gastrointestinal Complications Wall of distal colon damaged as eggs pass through, become lodged Inflammatory response can cause focal ulcers or polyps May develop diarrhoea, abdominal pain or colitis ?Predisposing factor for colorectal carcinoma

8 Hepatosplenic Complications Eggs may incite granulomatous response in liver May become walled off with dense layers of fibrous tissue Pipestem fibrosis - obstructs portal veins Leads to portal hypertension, oesophageal varices, splenomegaly

9 Genitourinary Complications Eggs lodged in bladder wall - inflammatory infiltrate around the egg Overlying bladder epithelium hyperplastic, polyps Polyps erode, ulcerate - cause hematuria Log standing and severe infections may lead to carcinoma Fibrosis may lead to ureteric stricturing, hydronephrosis

10 Ross A et al. N Engl J Med 2002;346:1212-1220 Clinical Findings in Two Patients Infected with Schistosoma Species

11 Other Complications Cardiopulmonary Complications: –Eggs from shunted portosystemic blood lodged in pulmonary arterioles –Granuloma formation, pulmonary hypertension, cor pulmonale Central nervous system: –Eggs deposited in spinal column transverse myelitis-like syndrome

12 Laboratory Diagnosis Microscopy –Detection of eggs in wet mounts of stool or urine –S. manoni has a lateral spine, S. haematobium has a terminal spine Rectal or bladder biopsies may be necessary Also antigen and antibody detection –Antibodies cross react with other helminth infections –Problematic in endemic areas

13 Kaplan B and Meyers K. N Engl J Med 2000;343:1085 An eight-year-old boy was referred to the nephrology clinic with a two-year history of painless, gross macroscopic hematuria

14 Management and Prevention Anti-schistosomal drugs –Praziquantel Symptomatic management of complications Chemoprophylaxis available Vaccines under development Snail control!

15 Bibliography Ross A.G.P., Bartley P.B. et al. Schistosomiasis. New Eng J Med 2002; 346(16): 1212-1219 Coon D.R. Schistosomiasis: Overview of the history, biology, clinicopathology, and laboratory diagosis. Clin Micro Newsletter 27(21): 163-169

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