Pediatric Schistosomiasis Treatment & Management
- Author: Vinod K Dhawan, MD, FACP, FRCP(C), FIDSA; Chief Editor: Russell W Steele, MD more...
Approach Considerations
Praziquantel is currently the main antischistosomal agent. Other oral agents are oxamniquine and metrifonate, but these have limited parasite specificity. Artemether appears to be beneficial in some settings.
Surgery may be necessary in severe or chronic schistosomiasis. Patients who have chronic liver disease or are experiencing further episodes of gastrointestinal (GI) bleeding or bacterial sepsis should be admitted for further inpatient care.
No special diet is required for acute disease. Individuals with chronic liver disease may benefit from a high-protein, low-salt diet. Limit activity for patients with acute GI bleeding or severe thrombocytopenia.
As a preventive measure, patients should be advised to avoid further freshwater contact in endemic areas if possible. An improved understanding of the immune response to schistosome infection suggests that development of a vaccine may be possible in the future.[12]
Pharmacologic Therapy
Praziquantel remains the drug of choice for treating all species of schistosomes.[13, 14] Typical dosages are 20 mg/kg orally twice daily on day 1 for S haematobium, S intercalatum,andS mansoni and 20 mg/kg orally 3 times daily on day 1 for S japonicumandS mekongi. Cure rates range from 65-90% after a single treatment.[15] Egg excretion is reduced by more than 90% in persons not cured.
Praziquantel appears to be safe during pregnancy, as demonstrated in a prospective study carried out in eastern Sudan involving 25 pregnant women with S mansoni infection.[16] The drug was given to 6 (24%), 12 (48%), and 7 (28%) of the women during the first, second, and third trimesters of their pregnancies, respectively. No stillbirths or congenital abnormalities were reported among the newborns. One patient aborted (3 weeks after treatment), but this rate of abortion was considered typical in the local community.
Patients should be monitored during therapy for any seizures or other neurologic consequences of dying cysticerci. Corticosteroid therapy has been used to reduce inflammation and mitigate reactions that develop in response to killing the parasites. Maturing schistosomes are less susceptible to chemotherapy than adult worms; therefore, a second course of therapy should be given several weeks after the first.
Oxamniquine has been used for treatment of S mansoni infections with equally good results, but this agent is no longer available in the United States.
Metrifonate is effective only against urinary schistosomes; it requires 3 doses administered 2 weeks apart and is not currently available in the United States.
Artemether can kill schistosomula during the first 3 weeks of infection and has been shown to be effective for prophylaxis in areas of high endemicity. Used as an antimalarial, artemether is also active against schistosome parasites (mainly schistosomula). Trials involving the combination of artemether and praziquantel show beneficial effect.
Surgical Management of Associated Conditions
Surgery may be necessary in severe or chronic schistosomiasis. Procedures that may be indicated include the following:
- Resection of bladder and colonic polyps
- Correction of obstructive uropathy
- Partial colectomy for GI polyposis and fibrosis
- Placement of a distal splenorenal shunt for reversal of portal hypertension
- Resection of cerebral cortical granulomas after failure of chemotherapy
Consultations
Consultations may be indicated with the following specialists:
- Infectious diseases specialist
- Gastroenterologist
- General surgeon
- Nephrologist
- Neurologist
- Neurosurgeon
- Urologist
Long-Term Monitoring
Patients who have been treated with antischistosomal chemotherapy should be monitored for treatment effectiveness. Stool and urine samples should be examined for 1 year after therapy. Successful therapy results in decreased in egg excretion.
Newer tests that measure antigens may help assess therapeutic response. Persistent circulating antigen and continued excretion of eggs indicate residual infection and the need for retreatment with praziquantel.
It should be kept in mind that serologic tests may remain positive for several years after successful treatment and thus may not be helpful as a test of cure.
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