Urinary Schistosomiasis

Introduction

Urinary Schistosomiasis is a common parasitic infection of the urinary tract caused by a body fluke, Schistosoma haematobium.
Infection occurs when your skin comes in contact with contaminated freshwater in which certain types of snails that carry schistosomes are living.  This could occur while swimming, bathing or wading in infected water.
It is endemic in many parts of Africa.
It gets to the urinary tract through the blood vessels after penetrating the skin.

Clinical features

Soon after penetration of the skin:

  • Pricking sensation and itching (cercarial dermatitis)

Four weeks later:

  • Intermittent fever, malaise, urticaria and cough

Six-24 months later:

  • Intermittent, painless terminal haematuria (may be total)
  • Symptoms of bladder irritability: dysuria, frequency, urgency, strangury

Differential diagnoses

  • Tuberculous cystitis
  • Abacterial cystitis
  • Bladder carcinoma

Complications

  • Bladder fibrosis and contracture
  • Ureteral stricture
  • Urethral stricture
  • Bladder calculi
  • Bladder cancer

Investigations

  • Urine examination for schistosomal ova
  • Cystoscopy: tubercles, sandy
    nodules, ulcers patches,
  • Plain abdominal radiograph (KUB)
  • Intravenous urogram
  • Serological tests
  • Full Blood Count

Treatment objectives

  • To eradicate the fluke and ova
  • Prevent complications

Drug treatment

Praziquantel
Praziquantel is the schistosomicide with the most attractive combination of effectiveness, broad spectrum activity and low toxicity

  • Adult: Single oral dose of 50 mg/kg
  • Child over 4 years: 20 mg/kg orally, repeated after 4-6 hours

In S. japonicum infection, 20 mg/kg 3 times daily for one day after initial dose

Notable adverse drug reactions, caution

  • Nausea, epigastric pain, pruritus, headache, dizziness

Prevention

  • Provision of and access to pipe-borne water
  • Improvement in socio-economic conditions
  • Mass chemotherapy in endemic areas
  • Eradicating the intermediate hosts (water snails)