Optic nerve sheath diameter ultrasonography for elevated intracranial pressure detection.

: Ultrasonographically measured optic nerve sheath diameter measurement has become a common noninvasive approach for detecting elevated intracranial pressure. We present a case of aneurysmal subarachnoid hemorrhage with elevated intracranial pressure. Postoperative arachnoiditis developed, and lumbar puncture revealed low intracranial pressure. However, ultrasonography revealed a dilated optic nerve sheath, denoting elevated intracranial pressure. This was confirmed by computed tomography showing ventricular dilation. Ophthalmoscopy revealed papilledema and hemorrhage. This case study demonstrated that noninvasive bedside ultrasonographic optic nerve sheath diameter measurement can detect elevated intracranial pressure more accurately than lumbar puncture, especially in cases with intracranial infection.