Sonographic Assessment of the Optic Nerve Sheath and Transorbital Monitoring of Treatment Effects in a Patient with Spontaneous Intracranial Hypotension: Case Report

Abstract
To investigate the potential of the ultrasound-based evaluation of the optic nerve sheath in a patient with spontaneous intracranial hypotension due to cervical cerebrospinal fluid (CSF) leakage. Repeated measurements of the optic nerve sheath diameter (ONSD) using B-mode sonography were performed before treatment initiation, during medical treatment, and during a course of repeated placement of epidural blood patches. On admission, transorbital sonography revealed a decreased ONSD of 4.1 mm on the right and 4.3 mm on the left side. After 8 months of treatment with caffeine and computed tomography-guided epidural blood patches a gradual distension of the ONSD into the normal range was bilaterally observed (right: 5.2 mm; left: 5.3 mm). The ultrasound-based evaluation of the optic nerve sheath may be helpful in detecting CSF hypovolemia and for determination of treatment effects. This report should be seen as a basis for future investigations on the sonographic assessment of the optic nerve sheath in diagnosis and treatment of intracranial hypotension.