Tetraventricular Hydrocephalus Due to Idiopathic Fourth Ventricle Outlet Obstruction: A Case Report and Literature Review.

Introduction: Tetraventricular hydrocephalus happens due to the fourth ventricle outlet obstruction. Idiopathic fourth ventricle outlet obstruction (IFVOO) is a condition where no clear-cut etiology for fourth ventricle outlet obstruction can be found. The etiopathogenesis of IFVOO is unclear. There is no clear-cut consensus regarding the treatment practices for its management. These cases present a diagnostic dilemma to the treating neurosurgeon and are thus often managed inappropriately. This study aims to review the existing literature regarding this condition, illustrating with a case from our hospital. Case Details: We present a case of a 50-year-old female who presented to us with the chief complaints of headache, difficulty in walking, with an inability to balance while standing and walking, diplopia, and three episodes of loss of consciousness for 6 months. A brain MRI was done, which was suggestive of dilatation of all ventricles with obstruction at the foramina of Luschka and Magendie. She underwent a right-sided, medium-pressure ventriculoperitoneal shunt at our hospital. Postsurgery, there was immediate improvement in her symptoms. Conclusion: IFVOO is a rare cause of tetraventricular hydrocephalus with an unknown cause. Endoscopic third ventriculostomy (ETV) appears to have a higher risk of failure in such cases. Fenestration procedures after craniotomy and shunt procedures are still effective in their management. ETV is still an alternative to the above-mentioned procedures. To confirm these conclusions, larger studies involving multiple hospitals and institutes are required.