PO-27 | A monitoring of intracranial hypertension through the valuation of optic nerve sheath diameter with bedside ultrasounds. A case report

Antonio Taglialatela,¹ Camilla Gaiga,¹ Simone Lorenzut,² Enrico Belgrado,² Mariarosaria Valente^1,3 | ¹Clinical Neurology Unit, Department of Head, neck and neurosurgery, Udine University Hospital, Udine; ²Neurology Unit, "Head, Neck and Neurosciences" Department, University Hospital of Udine; ³Department of Medical Area, University of Udine, Udine, Italy

Background: Headache is the most common clinical presentation of cerebral venous thrombosis (CVT). The most frequent symptoms reflect an intracranial hypertension syndrome, including headache, papilledema, and visual disturbances. Among diagnostic tools, orbital ultrasonography is emerging as a safe, accessible, and non-invasive method to detect elevated ICP. The optic nerve sheath diameter (ONSD), measurable via ultrasound due to the nerve's distinct anatomy, has shown good correlation with papilledema and elevated ICP in several studies, supporting its use as a bedside screening tool.

Methods: A 42-year-old male smoker presented in May 2024 with right-sided headache, periorbital pain, ipsilateral tearing, and rhinorrhoea. Imaging (CT, CT venography, and MRI) revealed cerebral venous thrombosis involving the superior sagittal, right transverse, and sigmoid sinuses, along with partial thrombosis of cortical veins in the bilateral fronto-parietal region. The patient was discharged on Rivaroxaban 20 mg daily. Follow-up imaging showed initial recanalization. From August 2024, he developed worsening headaches and bilateral visual disturbances. Repeat MRI revealed recurrent thrombosis, prompting readmission in October 2024. A CSF depletion test confirmed elevated intracranial pressure (21–22 mmHg) with partial clinical benefit. During treatment with corticosteroids and acetazolamide, we monitored the intracranial hypertension through the ultrasound valuation of ONSD and papilledema using a linear probe (10 MHz) positioned at the transpalpebral level. The ONSD was measured starting at 30 mm from the optic disc.

Results: We evaluated the optic nerve sheath diameter and the size of the optic disc using ultrasound before cerebrospinal fluid depletion and at 1 hour, 1 day, 3 days, and 15 days after the depletion. The measured values improved progressively, correlating with the patient’s clinical condition. ONSD before CSF depletion (0.57 cm OO) and after 15 days (0.47 cm OO). Papillae before CSF depletion (0.12 cm OO) and after 15 days (0.07 OD, 0.06 OS).

Conclusion: Cerebral venous thrombosis is a rare condition that primarily affects young adults. Patients sometimes present symptoms of intracranial hypertension such as headache, papilledema, and decreased visual acuity. Ultrasound measurement of the ONSD should be considered as a reliable and non-invasive tool to estimate and monitoring the increased intracranial pressure.