Impaired visual acuity as an only symptom of shunt malfunction, long time after initial cyst-peritoneal shunting for arachnoid cyst: A case report

Background: Long-term outcomes after surgical treatment of arachnoid cysts (ACs) have not been reported adequately. Impaired visual acuity is not a common symptom of shunt dependency syndrome due to cyst-peritoneal (CP) shunt malfunction for ACs. We report a case of CP shunt malfunction, who presented only impaired visual acuity as a symptom, long after the initial surgical treatment. Case Description: A 16-year-old boy was surgically treated for the left frontal AC with CP shunting at 2 years of age. Extension of the peritoneal shunt catheter was performed at 15 years of age. A year later, he started experiencing impairment of visual acuity without headaches, which worsened to bilateral light perception. The presence of bilateral optic atrophy was confirmed. The AC in the left frontal lobe had enlarged very slightly, with shortening of the intracystic catheter, and the cerebrospinal fluid pressure was elevated to 30 cmH2O. He was treated with lumboperitoneal shunting. The visual acuity showed limited improvement. Conclusion: The possibility of CP shunt malfunction and shunt dependency syndrome should be considered, even if the patient presented only impaired visual acuity and no significant changes in the size of the ACs are observed.