Trapped fourth ventricle: A case report and review of literature.

Introduction And Importance: Trapped fourth ventricle (TFV) also known as isolated fourth ventricle (IFV) is a rare clinico-radiologic entity with only a few cases reported in the literatures. The aim of this article is to present the first case of this condition in our center and highlight the challenges of arriving at clinical diagnosis and treatment in a resource limited setting.

Case Presentation: An 18 months old girl who had ventriculoperitoneal shunt insertion for post meningitic hydrocephalus 4 months earlier presented with restlessness, ataxia, fever and inability to control her neck of one-week duration. On examination she was restless and had retro-colis with a Glasgow Coma Scale (GCS) score of 11/15 (E4V2M5). She had an associated facial and abducent nerve palsies with global hypertonia, hyper-reflexia and muscle power of 3/5. She was initially treated for shunt infection and malfunction. However, shunt series and CSF analysis were within normal limits and CSF culture yielded no growth of microorganisms. A CT scan of the brain which was ordered earlier was delayed for 10 days due to financial constraints. The CT scan revealed a trapped fourth ventricle and slit lateral and third ventricle. She had emergency fourth ventriculoperitoneal shunt inserted on the left because of the pre-existing supratentorial shunt on the right. She did well after the surgery and was discharged on the 10th postoperative day. She was doing well 12 months after the surgery.

Relevance And Impact: TFV may occur after insertion of VPS for post-meningitic hydrocephalus. This may present a diagnostic dilemma. Insertion of a second VPS may be an option in a resource limited setting.