Shunt Dependency Syndrome Combined with Sinus Stenosis after Cyst-peritoneal Shunting of Arachnoid Cyst: A 20-year Rare Complication.

Shunt dependence syndrome is a serious long-term complication characterized by symptoms and signs of increased intracranial pressure with normal-sized lateral ventricles after several years of arachnoid cyst-peritoneal shunting. It is easy to misdiagnose and overlook when combined with sinus stenosis, thus delaying treatment. Here, we present a 35-year-old man with an unexplained headache and binocular horizontal diplopia with high intracranial pressure. Based on stenosis of the right transverse sinus and absent filling of the left transverse sinus found by cerebral angiography, we first suspected cerebral venous sinus thrombosis (CVST). However, the treatment of anticoagulation and enhanced dehydration did not work. Twenty years ago, he had a cyst-peritoneal (CP) shunt performed for an asymptomatic arachnoid cyst. Finally, neurosurgeons ruled out CVST by direct retrograde cerebral venography and diagnosed shunt dependence syndrome. All his symptoms resolved well after ventriculoperitoneal (VP) shunt treatment. This case reminds pediatrics and neurology colleagues to consider shunt dependence syndrome first when someone has a history of CP shunting of arachnoid cysts presented with a severe headache, even if imaging shows a thin or occlusive venous sinus. Once high intracranial pressure secondary to shunt dependence is diagnosed, timely reconstruction of the cerebrospinal fluid (CSF) pathway is recommended rather than osmotic therapies because cerebral herniation formation will be life-threatening if ongoing increased intracranial pressure is not relieved.