Destructive subependymal cysts following ventriculitis-pathomechanisms and treatment.

Ventriculitis may complicate neurosurgical procedures, for example, due to shunt or external ventricular drainage infection. Clearance of the infection with subsequent intravenous antibiotic therapy and shunt reinsertion, if necessary, are the standard treatment procedures with a high rate of success. Here, we report on a protracted complication, the development of destructive subependymal cysts, illustrate its treatment and discuss the pathomechanisms. The 2-year-and-9-month-old girl was admitted 5 weeks after a shunt revision with symptoms of shunt infection. Ventriculitis caused by Streptococcus salivarius (S. salivarius) was diagnosed and intravenous antibiotic treatment was performed. A new shunt system was implanted after clearance of infection and the girl did not show clinical signs of infection thereafter. A routine follow-up magnetic resonance imaging (MRI) revealed progressive and space-occupying multifocal subependymal cysts with partial destruction of the corpus callosum including compression of the ventricular system. Endoscopic broad-based laser fenestration of all cysts resulted in sustained regression of cavity formation. The cognitive development of the girl assessed 2 years afterward was completely normal. We conclude that routine follow-up MRI investigations are recommended 6 months after successful treatment of ventriculitis to detect protracted postinflammatory destructive subependymal cyst formations. Endoscopic broad-based laser-assisted cyst fenestration can stop progression and lead to regression of postinfectious subependymal cysts.