This prospective observational study investigates the potential of point-of-care ultrasonography of the optic nerve sheath diameter (ONSD) to rule out papilledema in patients with suspected hypertensive emergency. The primary focus is on assessing ONSD sensitivity in identifying papilledema (hypertensive retinopathy grade 4), while secondary endpoints include hypertensive retinopathy grade 3, hypertensive encephalopathy, and the need for intravenous rapid-acting medications to lower elevated blood pressure. This study aims to determine the diagnostic characteristics of this procedure for the diagnosis of hypertensive retinopathy, thus assessing its potential as a screening tool to rule out hypertensive retinopathy by the acute internal medicine doctor.

Inclusion Criteria:

• ≥ 18 years old
• Any patient presenting to the emergency department (ED) with suspected hypertensive emergency i.e.: blood pressure of > 200 millimetres of mercury (mmHg) systolic and/or > 120 mmHg diastolic

Exclusion Criteria:

• Patients with preexisting optic nerve head changes such as glaucoma, pre-existing retinal artery/vein occlusions or any other condition that makes assessment of the fundi impossible.
• Primary neurological cause of hypertension: ischemic cerebrovascular incident

Patients presenting to the emergency department with suspected hypertensive emergency.