Emergent Management of Acute Schistosomiasis 

Owing to increased population flow from areas where schistosomiasis is endemic, emergent management of acute schistosomiasis is likely to become a matter of increased concern. Schistosomiasis (also known as bilharzia, bilharziasis, bilharziosis, or snail fever) is a human disease syndrome caused by infection from one of several species of parasitic trematodes of the genus Schistosoma. Schistosomiasis is a major source of morbidity and mortality for developing countries in Africa, South America, the Caribbean, the Middle East, and Asia.

Tourism to and immigration from endemic areas can result in schistosomiasis cases presenting anywhere in the developed world. Acute schistosomiasis among travelers may be increasing, and rates of emigration from endemic areas are rising. In the complete absence of routine presymptomatic screening of these groups in developed countries, it is increasingly likely that patients with acute or chronic schistosomiasis will present to emergency departments (EDs) with a variety of complaints in nonendemic areas.^{[1, 2]}

Pediatric and adolescent patients who have traveled or lived in endemic areas are at the highest risk for exposure to schistosomes and are at risk for serious long-term complications. These patients usually respond well to drug therapy and should receive aggressive treatment and follow-up care.

Most human schistosomiasis is caused by S haematobium, S mansoni, or S japonicum. Less prevalent species, such as S mekongi and S intercalatum, may also cause systemic human disease. Less importantly, other schistosomes with avian or mammalian primary hosts can cause severe dermatitis in humans (eg, swimmer's itch secondary to Trichobilharzia ocellata).^{[3, 4, 5, 6, 7, 8, 9]}

Prior to the patient’s arrival at the hospital, support and stabilization are provided for acute complications of infection, if present. These might include volume depletion, heart failure, and gastrointestinal (GI) bleeding.

Emergency department care

In the emergency department (ED), the physician confirms the diagnosis, begins antibiotic therapy, and stabilizes patients with acute complications of schistosomiasis. Management of hepatosplenic,^{[10, 11]} GI, urinary, cardiopulmonary, and central nervous system (CNS) complications are summarized as follows:

• Volume depletion secondary to diarrhea - Rarely severe, and is treated with intravenous or oral volume replacement; minor lower GI bleeding and chronic anemia may be present but rarely require transfusion
• Portal hypertension with hematemesis - Treatment with fluid resuscitation, transfusion, endoscopic therapy, or surgery may be required
• Urinary obstruction - May require stenting or other drainage procedures
• Salmonella (or other gut source) sepsis - May require antibiotics and fluids
• Pulmonary hypertension and cor pulmonale - May require oxygen, diuresis, antiarrhythmics, or other interventions
• Cerebral infection - May require seizure control or management of intracranial pressure
• Transverse myelitis - May require steroids and supportive care as well as antihelminthic therapy

Definitive therapy can be initiated and often completed in the ED if the diagnosis is clear. During acute infections, antihelminthic treatment may at first exacerbate symptoms as a result of increased antigen release, usually requiring corticosteroid support. Treatment may produce a Loefflerlike syndrome in cases of heavy infestation, which may require pulmonary support.

In the case of pregnant patients, physicians may prefer to defer treatment of schistosomiasis until after the first trimester.^[12]

Consultations

Clearly communicating with the hospital's diagnostic laboratory personnel is crucial for optimal egg detection in stool and urine specimens.^{[13, 14]} Consult specialists as indicated by the complications present or the need for diagnostic procedures, such as colonoscopy.

Treatment of schistosomiasis is unusual in that only 1 drug, Praziquantel, is widely in use. Drug resistance has been reported and can be produced in laboratory settings but appears still to be uncommon in human infections. Myrrh derivatives have not demonstrated success in testing, but artemisinins^[15] are showing efficacy, and trioxolanes^[16] also show promise as future drugs.

Drug regimens result in curing the infection in 60-98% of cases and reduce egg burden in the remainder. Dead eggs may continue to shed for months, but treatment should arrest egg-laying, granuloma formation, and future complications. Although frank fibrosis may not reverse, evidence indicates that portal and pulmonary hypertension from granulomatous changes may improve significantly after treatment, particularly in younger patients.

Inpatient care

Initiate inpatient care for unstable patients with complications, such as GI bleeding, decompensated heart failure, and toxicity, according to the usual indications. Inpatient care is indicated for CNS infections.

Outpatient care

Reevaluate patients for symptom resolution and determination of cure. For uncomplicated cases, 4-6 weeks is the optimal follow-up time, corresponding with the maturation of eggs and immature worms that may have survived initial treatment. Retreatment is indicated after reexposure and reinfection. Patients with likely ongoing exposure may benefit from annual treatment in addition to education to reduce exposure risk.

Response may be evaluated by quantitatively decreased egg counts from urine or stool specimens or by antigen testing. Some patients require retreatment. Patients with evidence of portal hypertension, pulmonary hypertension, CNS infection, or urinary obstruction require long-term follow-up care.