Follow-up study of high-dose praziquantel therapy for cerebral sparganosis

Abstract

Background: Cerebral sparganosis is the most serious complication of human sparganosis. Currently, there is no standard for the treatment of inoperable patients. Conventional-dose praziquantel therapy is the most reported treatment. However, the therapeutic outcomes are not very effective. High-dose praziquantel therapy is a useful therapeutic choice for many parasitic diseases that is well tolerated by patients, but it has not been sufficiently evaluated for cerebral sparganosis. This study aims to observe the prognoses following high-dose praziquantel therapy in inoperable patients and the roles of MRI and peripheral eosinophil absolute counts during follow-up.

Methodology: Baseline and follow-up epidemiological, clinical, radiological and therapeutic data related to 10 inoperable patients with cerebral sparganosis that were treated with repeated courses of high-dose praziquantel therapy, with each course consisting of 25 mg/kg thrice daily for 10 days were assessed, followed by analyses of the prognoses, MRI findings and peripheral eosinophil absolute counts.

Principal findings: Baseline clinical data: the clinical symptoms recorded included seizures, hemiparesis, headache, vomiting and altered mental status. Peripheral blood eosinophilia was found in 3 patients. The baseline radiological findings were as follows. Motile lesions were observed in 10 patients, including aggregated ring-like enhancements, tunnel signs, serpiginous and irregular enhancements. Nine of the 10 patients had varying degrees of white matter degeneration, cortical atrophy and ipsilateral ventricle dilation. The follow-up clinical data were as follows. Clinical symptom relief was found in 8 patients, symptoms were eliminated in 1 patient, and symptoms showed no change from baseline in 1 patient. Peripheral blood eosinophilia was found in 2 patients. The follow-up radiological findings were as follows. Motile lesions that were transformed into stable, chronic lesions were found in 8 patients, and motile lesions that were eliminated completely were found in 2 patients.

Conclusions: High-dose praziquantel therapy for cerebral sparganosis is effective. The radiological outcomes of motile lesions are an important indicator during the treatment process, especially during follow-ups after clinical symptoms have improved. Peripheral eosinophil absolute counts cannot be used as an effective prognostic indicator.

Fig 1. For the purpose of assessing clinical improvements, follow up times were grouped into time periods of 3–6 months, 7–9 months, 10–13 months and greater than 13 months.

Most of the patients experienced an improving trend in clinical symptoms within 9 months after the first treatment, and a small number of patients with poor initial treatments presented with improved clinical symptoms during the 10–30 months after treatment.

Fig 2. Axial and sagittal images of a 45-year-old male patient with a 3-month history of right hemiparesis.

Case 6. An axial and sagittal T1 FLAIR image shows that there are serpiginous and irregular enhanced lesions in the left frontal and parietal lobes (white arrows) at baseline MRI. After 2 courses of therapy (10 months later) and follow-ups for 25 months, the left frontal and parietal lobe lesions disappeared completely, and no stable, chronic lesions occurred.

Fig 3. Axial images of a 22-year-old female patient with a 15-year history of seizures.

Case 8. (A) (H). An axial T1 FLAIR image shows that there are aggregated ring-like, serpiginous and irregular enhanced lesions in the left frontal and parietal lobes (white arrows) at baseline MRI. White matter degeneration and cortical atrophy were found in the left frontal lobe (white open arrow) at baseline MRI. (B-G) (I-N). An axial T1 FLAIR image shows that after 2 courses of high-dose praziquantel therapy (7 months later), the left frontal lobe motile lesions disappeared. However, the initial aggregated ring-like and serpiginous enhanced lesions in left frontal lobe (white arrows) and parietal lobes reoccurred 10 months later. After 4 courses of therapy (17 months later), the extent of the left frontal lobe lesions (white arrow) are reduced significantly, and the left parietal lobe lesions disappeared. After 5 courses of therapy (23 months later) and follow-ups for 30 months, the left frontal lobe lesions disappeared completely, and white matter degeneration and cortical atrophy occurred in the corresponding area. (O-T) An axial FLAIR image shows that migrated lesions occurred in the left temporal lobe (3 months later) (white arrow and white open arrow) and the basal ganglia (7 months later) (white arrowhead) in follow-up MRI. After 2 courses of therapy (10 months later), the migrated lesions disappeared completely, and no long-standing lesions occurred.

Fig 4. The distributions of motile and migrated lesions in brains.

The motile and migrated lesions often involve the frontal, parietal, and temporal lobes and the basal ganglia but rarely involve the occipital lobe and the cerebellum.