A proposed mechanism for intracranial venous lake thrombosis in patients with intracranial signs of hypotension after dural instrumentation.

Introduction: Dural sinus venous thrombosis in postpartum women is a well known complication, but intracranial venous lake thrombosis (IVLT) has not been previously described, nor its association with intracranial hypotension following epidural anesthesia (EDA). This study aims to describe and characterize a cohort of patients with IVLT with regards to imaging findings and symptoms. Materials and methods: This retrospective study included patients from the picture and archiving communication system based on search strategies from referral text including: "headache + EDA", "complicated EDA", "post dural puncture headache", "childbirth + headache", "delivery + headache" between November 2005 and June 2024. Retrieved examinations were screened for IVLT, intracranial venous thrombosis, and radiological signs of intracranial hypotension. Patient data were extracted and presented descriptively. Results: Out of 201 patients with 300 investigations, 12 patients (12/201, 6%) had imaging findings suggestive of IVLT. Out of these, 83% (10/12) were in the postpartum period and had received an EDA during delivery, with three (3/12, 25%) stating in the referral that the EDA had been complicated to obtain, with multiple attempts. The mean (SD) Bern score was 6.25 (1.22), indicating a high risk for dural leak. Imaging findings of IVLT included high attenuating thrombotic structures in the parasagittal venous lakes on the inside of the skull convexity on CT with lack of contrast media filling at venous CT-angiography. Conclusion: We propose a mechanism for intracranial venous lake thrombosis (IVLT) in postpartum females with headaches after complicated EDA with signs of intracranial hypotension.