[Ultrasound diagnosis of bilharziasis]

Ultrasonography of gallbladder abnormalities due to schistosomiasis

After malaria, schistosomiasis remains the most important tropical parasitic disease in large parts of the world. Schistosomiasis has recently re-emerged in Southern Europe. Intestinal schistosomiasis is caused by most Schistosoma (S.) spp. pathogenic to humans and leads to chronic inflammation and fibrosis of the colon as well as to liver fibrosis. Gallbladder abnormalities usually occur in patients with advanced hepatic portal fibrosis due to Schistosoma mansoni infection. Occasionally, gallbladder abnormalities have been seen also in children and occurring without associated overt liver abnormalities.The specific S. mansoni-induced gallbladder abnormalities detectable by ultrasound include typical hyperechogenic wall thickening with external gallbladder wall protuberances. The luminal wall surface is smooth. The condition is usually clinically silent although some cases of symptomatic cholecystitis have been described. The ultrasonographic Murphy response is negative. Gallbladder contractility is impaired but sludge and calculi occur rarely. Contrary to other trematodes such as liver flukes, S. mansoni does not obstruct the biliary tract. Advanced gallbladder fibrosis is unlikely to reverse after therapy.

Drugs for treating urinary schistosomiasis

BACKGROUND

Urinary schistosomiasis causes long-term ill-health. This review examines the various treatment options and newer drugs.

OBJECTIVES

To evaluate antischistosomal drugs, used alone or in combination, for treating urinary schistosomiasis.

SEARCH STRATEGY

In August 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, LILACS, mRCT, and reference lists of articles. We also contacted experts in schistosomiasis research.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of praziquantel, metrifonate, artemisinin derivatives, or albendazole, alone or in combination, versus placebo, different doses, or other antischistosomal drugs for treating urinary schistosomiasis.

DATA COLLECTION AND ANALYSIS

One author extracted data, and assessed eligibility and methodological quality, which were cross-checked by a second person. Dichotomous outcomes were combined using risk ratio (RR), and continuous data were combined using weighted mean difference (WMD); both presented with 95% confidence intervals (CI).

MAIN RESULTS

Twenty-four trials (6315 participants) met the inclusion criteria. Compared with placebo, participants receiving metrifonate had fewer parasitological failures at follow up at one to three months (1 trial) and three to 12 months (3 trials). Egg reduction rate was over 90%, and no adverse events were reported (1 trial). One metrifonate dose was inferior to three doses given fortnightly (both used 10 mg/kg). Praziquantel (standard single 40 mg/kg oral dose) was more effective than placebo at reducing parasitological failure at one to three months' follow up and three to 12 months. Egg reduction rates were improved with praziquantel (over 95% versus 5.3% to 64% with placebo). Mild to moderate adverse events were recorded in two trials. A comparison of metrifonate (10 mg/kg x 3, once every 4 months for one year) with praziquantel (standard dose) showed little difference in parasitological failure. For praziquantel, there was no significant difference in effect between 20 mg/kg x 2, 30 mg/kg x 1, and 20 mg/kg x 1, and the standard dose for all outcomes. One small trial of artesunate showed no obvious benefit compared with placebo, and the artesunate-praziquantel combination was similar to praziquantel alone.

AUTHORS' CONCLUSIONS

Praziquantel and metrifonate are effective treatments for urinary schistosomiasis and have few adverse events. Metrifonate requires multiple administrations and is therefore operationally less convenient in community-based control programmes. Evidence on the artemisinin derivatives is currently inconclusive, and further research is warranted on combination therapies. We suggest metrifonate be reconsidered for the WHO Model List of Essential Medicines.