High-dose praziquantel therapy for cerebral sparganosis

A 39-year-old Bangladeshi man was admitted to our hospital with a first generalized epileptic seizure. Brain MRI showed multiple ring-enhancing lesions with perifocal edema (Fig. 1a and g, February 2008). CSF analysis showed 8 cells/ll and normal protein, glucose and lactate levels. Serum and CSF serological tests were negative for a broad range of parasites, fungi and bacteria. The patient was suspected to have neurocysticercosis and was treated with albendazole (400 mg bi-daily for 30 days). However, follow up MRI showed new, adjacent lesions with ringand tunnel-shaped enhancement; and punctate calcifications in the left parieto-occipital area in the CT scan (Fig. 1b, h and m, December 2009), suggesting that the treatment had been ineffective. We therefore performed a brain biopsy (with prior MRI for the localization of the sparganum, see Fig. 1c and i, February 2010), which revealed a degenerated cyst containing membrane-shaped structures with multiple foci of calcification. PCR was positive for Spirometra erinaceieuropaei, leading to the diagnosis of cerebral sparganosis. Surgical removal of the parasite is the treatment of choice as standard anti-helmintic therapy is considered ineffective in sparganosis [1–3]. The repeated MRI indicated that the lesion had been wandering again (Fig. 1d and j). An ethylcholine PET showed a defined region with increased tracer uptake, most likely indicating the current location of the sparganum (Fig. 1n). However, the patient refused the recommended stereotactic surgery. We therefore treated the patient with a high-dose regimen of praziquantel (3 9 25 mg/kg body weight daily) for 7 days combined with cimetidine (3 9 400 mg daily) and a high carbohydrate diet to increase plasma levels of praziquantel [4]. The treatment was well-tolerated. Follow-up MRIs 3 and 11 months later showed drastic improvement and the ethylcholine PET had normalized (Fig. 1e, f, k, l, o and p). Anti-sparganum antibody levels were determined from preserved CSF and serum samples by a specific ELISA [5]. Before therapy (Fig. 1, December 2009), anti-sparganum antibody levels were elevated in the serum (0.29) and in the CSF (0.55 normal value in serum and CSF \ 0.22). After therapy (Fig. 1, June 2011), antibody levels had dropped to 0.09 in serum (a lumbar puncture was not repeated after therapy). Seizures discontinued and anticonvulsive treatment was slowly tapered. Sparganosis is a rare parasitic disease caused by infestation with the larval cestode of Spirometra spp. Most cases have been reported in Southeast and Eastern Asia. Humans are infected by drinking unfiltered, contaminated water or through consumption of raw snakes and frogs. When the parasite invades the central nervous system, epileptic seizures and headache are common symptoms [2]. Characteristic MRI findings of cerebral sparganosis include a R. R. Gonzenbach (&) M. Weller A. Semmler Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland e-mail: roman.gonzenbach@usz.ch