Orbital - Normal ONSD
Caption
A 35 yo female presented to a rural ED with worsening headache accompanied by nausea/vomiting after failed treatment for sinusitis. The department did not have immediate access to CT scanning, therefore Optic Nerve Sheath Diameter (ONSD) was used to assess for associated increased intracranial pressure. The optic nerve sheath is contiguous with the subarachnoid space, making ONSD an indirect measure of intracranial pressure. Visualize the hypoechoic optic nerve posterior to the globe and measure 3mm back from the globe (calipers A) to determine site of measurement . Then measure to the edges of the sheath (calipers B) horizontally. Value >5mm is concerning for increased ICP. This ONSD is normal. Mandy Peach, MD @mandy_peach Saint John Regional Hospital. NB, Canada