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Referral and warning signs
When to refer
Refer patients with complications (portal hypertension/haematemesis, severe hydronephrosis, suspected bladder cancer, neuroschistosomiasis) to specialist care (H/RR). Refer for diagnosis confirmation if needed.
Red flags
- Haematemesis or severe melena (variceal bleeding).
- Signs of severe liver disease (ascites, jaundice).
- Signs of severe kidney damage / renal failure.
- Neurological symptoms (seizures, paralysis).
Signs and symptoms
- Early Stage (Cercarial Dermatitis / Swimmer's Itch): Itchy papular rash at site of cercarial skin penetration (minutes to days after exposure).
- Acute Schistosomiasis (Katayama Fever): Occurs 2-12 weeks post-exposure (esp. non-immune individuals). Systemic hypersensitivity reaction: Fever, chills, cough, muscle aches, headache, abdominal pain, diarrhoea, urticaria, eosinophilia. Often resolves spontaneously but indicates heavy infection.
- Chronic Intestinal Schistosomiasis (S. mansoni, S. japonicum, S. mekongi, S. intercalatum):
- - Abdominal pain, diarrhoea (may be bloody/mucoid), fatigue.
- - Hepatosplenomegaly (due to egg deposition/granulomas in liver).
- - Periportal fibrosis -> Portal hypertension -> Oesophageal varices, Ascites, Haematemesis (late, severe complication).
- Chronic Urinary Schistosomiasis (S. haematobium):
- - Terminal Haematuria: Blood in urine, especially at the end of urination (classic sign).
- - Dysuria, increased urinary frequency.
- - Bladder wall inflammation, fibrosis, calcification.
- - Hydroureter, Hydronephrosis (due to ureteric obstruction).
- - Increased risk of bladder cancer (Squamous Cell Carcinoma).
- - Genital schistosomiasis (females: lesions on cervix/vagina, bleeding, pain, infertility; males: seminal vesicle/prostate involvement).
- Neuroschistosomiasis (Rare): Egg deposition in brain or spinal cord causing seizures, myelopathy.
Risk factors
- Contact with contaminated freshwater bodies (rivers, lakes, ponds, irrigation canals) in endemic areas (swimming, bathing, washing, fishing, farming).
- Lack of access to safe water and sanitation.
- Presence of specific snail intermediate hosts.
Diagnosis
Clinical assessment
Suspicion based on symptoms (haematuria, bloody diarrhoea, hepatosplenomegaly) + history of freshwater exposure in endemic area. Katayama fever diagnosis often missed.
Differential diagnosis
- Intestinal: Amoebiasis, Shigellosis, IBD, Other causes of bloody diarrhoea/hepatosplenomegaly.
- Urinary: UTI, Kidney stones, Bladder tumour, TB.
- Katayama Fever: Malaria, Typhoid, Viral illness, Drug reaction.
Investigations
- Microscopy (Detection of Eggs):
- - Urine Sedimentation/Filtration: For S. haematobium eggs (examine midday urine sample).
- - Stool Examination (Kato-Katz technique preferred): For S. mansoni eggs (or other intestinal species). Multiple samples increase sensitivity.
- - Rectal Snip/Biopsy: Higher sensitivity for light S. mansoni infections.
- Serology (Antibody detection): Useful for travellers or light infections where eggs hard to find. Cannot distinguish active from past infection.
- Antigen Detection: POC tests detecting circulating antigens available (e.g., CCA for S. mansoni in urine).
- Ultrasound: Assess hepatosplenomegaly, periportal fibrosis (S. mansoni), bladder wall thickening/calcification, hydronephrosis (S. haematobium).
- FBC: Eosinophilia common, anaemia.
Diagnostic criteria
Demonstration of Schistosoma eggs in urine, stool, or tissue biopsy. OR Compatible clinical picture + Positive antigen/antibody test + Epidemiological link.
Management
Non-pharmacological management
- Supportive care.
- Management of complications (e.g., portal hypertension, bladder cancer).
Pharmacological treatment
- Anthelmintic Treatment (Schistosomicide):
- - Praziquantel: Drug of choice for ALL Schistosoma species. Highly effective, safe, single oral dose.
- - Dose: 40 mg/kg PO single dose (for S. haematobium, S. mansoni).
- - Dose: 60 mg/kg PO divided into 2-3 doses over one day (for S. japonicum, S. mekongi).
- - (LOC: HC4+ / MDA Programs)
- - Treatment may need repeating after 4-6 weeks if heavy infection or re-exposure.
- Management of Katayama Fever: Corticosteroids (e.g., Prednisolone) may be needed to control severe hypersensitivity symptoms, along with Praziquantel.
Monitoring
Monitor for side effects of Praziquantel (usually mild - dizziness, headache, nausea). Re-check stool/urine for eggs 1-3 months post-treatment to assess cure (especially in individual cases). Monitor organ damage (ultrasound).
Complications
- Chronic anaemia.
- Growth retardation / Malnutrition (children).
- Hepatic fibrosis / Portal hypertension / Variceal bleeding.
- Bladder fibrosis / Calcification / Obstruction / Cancer.
- Hydronephrosis / Renal failure.
- Infertility / Ectopic pregnancy (genital schistosomiasis).
- Pulmonary hypertension (due to eggs embolizing to lungs).
- Neuroschistosomiasis.
Prevention
- Mass Drug Administration (MDA): Periodic treatment with Praziquantel for school-aged children and high-risk adults in endemic areas.
- Snail Control: Mollusciciding (chemical application to kill snails) or environmental management.
- Improved Sanitation and Safe Water Access: Reduce contamination of water bodies.
- Health Education: Avoid contact with contaminated water, promote safe water/sanitation practices.
- Treatment of infected individuals.
Patient education
- Explanation of Bilharzia, transmission via water contact.
- Importance of taking Praziquantel treatment.
- Potential side effects (usually mild).
- Avoiding contact with potentially contaminated water.
- Using safe water sources.
- Proper sanitation (avoid urinating/defecating in water).
- Importance of community MDA programs.
Uganda-specific notes
Both S. mansoni (intestinal - lakes/rivers) and S. haematobium (urinary - less common, specific foci) are endemic. Affects communities around Lake Victoria, Lake Albert, Nile river, etc. Control relies heavily on MDA with Praziquantel in schools and high-risk communities.
References
- Uganda Clinical Guidelines (UCG) 2023
Chapter 2, Section 2.4.6
- National Schistosomiasis Control Programme Guidelines, MOH Uganda
(Specific program documents)