Case Report: Moving Tumor-Like Foci Behind Refractory Epilepsy-Cerebral Sparganosis Successfully Treated by Surgery After Failure of Praziquantel Treatment

Cerebral sparganosis in a child with corpus callosum invasion: a case report

BACKGROUND

Invasion of the corpus callosum by sparganosis is rare in children. After invading the corpus callosum, sparganosis has various migration modes, which can break through the ependyma and enter the ventricles, thus causing secondary migratory brain injury.

CASE PRESENTATION

A girl aged 4 years and 7 months presented with left lower limb paralysis for more than 50 days. Blood examination showed that the proportion and absolute number of eosinophils in the peripheral blood were increased. Furthermore, enzyme-linked immunosorbent assay of serum and cerebrospinal fluid samples revealed positivity for IgG and IgM antibodies for sparganosis. Initial magnetic resonance imaging (MRI) revealed ring-like enhancements in the right frontoparietal cortex, subcortical white matter, and splenium of the corpus callosum. Within 2 months, a fourth follow-up MRI showed that the lesion had spread to the left parietal cortex, subcortical white matter, and deep white matter in the right occipital lobe and right ventricular choroid plexus, with left parietal leptomeningeal enhancement.

CONCLUSION

Migratory movement is one of the characteristics of cerebral sparganosis. When sparganosis invades the corpus callosum, clinicians should be aware that it may then break through the ependyma and enter the lateral ventricles, leading to secondary migratory brain injury. Short-term follow-up MRI is necessary to evaluate the migration mode of sparganosis and dynamically guide treatment strategies.

Natural variation in the binding pocket of a parasitic flatworm TRPM channel resolves the basis for praziquantel sensitivity

The drug praziquantel (PZQ) is the key clinical therapy for treating schistosomiasis and other infections caused by parasitic flatworms. A schistosome target for PZQ was recently identified- a transient receptor potential ion channel in the melastatin subfamily (TRPM_PZQ)-however, little is known about the properties of TRPM_PZQ in other parasitic flatworms. Here, TRPM_PZQ orthologs were scrutinized from all currently available parasitic flatworm genomes. TRPM_PZQ is present in all parasitic flatworms, and the consensus PZQ binding site was well conserved. Functional profiling of trematode, cestode, and a free-living flatworm TRPM_PZQ ortholog revealed differing sensitives (~300-fold) of these TRPM_PZQ channels toward PZQ, which matched the varied sensitivities of these different flatworms to PZQ. Three loci of variation were defined across the parasitic flatworm TRPM_PZQ pocketome with the identity of an acidic residue in the TRP domain acting as a gatekeeper residue impacting PZQ residency within the TRPM_PZQ ligand binding pocket. In trematodes and cyclophyllidean cestodes, which display high sensitivity to PZQ, this TRP domain residue is an aspartic acid which is permissive for potent activation by PZQ. However, the presence of a glutamic acid residue found in other parasitic and free-living flatworm TRPM_PZQ was associated with lower sensitivity to PZQ. The definition of these different binding pocket architectures explains why PZQ shows high therapeutic effectiveness against specific fluke and tapeworm infections and will help the development of better tailored therapies toward other parasitic infections of humans, livestock, and fish.