Schistomiasis

B65.0-3/B65.8-9

*Notifiable medical condition.

DESCRIPTION

A parasitic infestation with:

  • Schistosoma haematobium: primarily involves the bladder and renal tract, or
  • Schistosoma mansoni: primarily involves the intestinal tract.

DIAGNOSIS

Acute schistosomiasis syndrome

  • Typically occurs in travellers to endemic areas with freshwater exposure 3-7 weeks before onset.
  • Clinical features include fever, rigors/chills, urticaria,angioedema, myalgias, arthralgias, dry cough, diarrhea, abdominal pain, and headache. Symptoms are usually relatively mild and resolve spontaneously over a period of a few days to a few weeks.
  • The eosinophil count is almost invariably markedly elevated.
  • Diagnosis is confirmed serologically – eggs are seldom seen in stool or urine.
  • Differential diagnosis includess urinary tract infection, glomerulonephritis, HIV, gastroenteritis (Salmonella), hepatitis A, B and C, malaria.

Chronic schistosomiasis

  • Most individuals with schistosomiasis infection are asymptomatic.
  • S. haematobium may present with macroscopic haematuria and urinary symptoms. Chronic bladder involvement and urinary tract involvement may cause urinary incontinence and obstructive uropathy.
  • S. mansoni may present with chronic or intermittent dysentery. Periportal fibrosis and portal hypertension may occur.
  • Pulmonary hypertension and central nervous system involvement (particularly myelopathy) are uncommon complications.
  • Definitive diagnosis is by finding eggs in urine (S. haematobium), stool (S. mansoni), or on biopsy. Serology is usually positive.

MEDICINE TREATMENT

Acute schistosomiasis syndrome

  • Corticosteroids (intermediate-acting) e.g.:
    • Prednisone, oral, 40 mg daily for 5 days.

LoEIII [23]

4-6 weeks later, after symptoms have resolved:

  • Praziquantel, oral, 40 mg/kg as a single dose.

LoEIII [24]

AND

  • Corticosteroids (intermediate-acting) e.g.:
    • Prednisone, oral, 40 mg daily for 5 days.

Optimum time for administration of praziquantel is uncertain but sufficient time is required for the worms to mature.

If in 4-6 weeks, eosinoplilia present and high antibody titres, repeat praziquantel treatment:

  • Praziquantel, oral, 40 mg/kg as a single dose.

LoEIII [25]

Chronic schistosomiasis

Manage as recommended in PHC STGs and EML, Schistosomiasis (bilharzia)