Ultrasound of the Eye As a Screening Tool For Increased Intracranial Pressure Among Patients Presenting with Headache At the ED of St. Luke’s Medical Center
Background: When a patient presents at the emergency room with headache, the ER physician will likely be focused on eliminating the possibility of life-threatening diseases. However, only a subset of patients with this complaint is found to have life-threatening intracranial pathology upon imaging. Increased use of imaging has been associated with higher costs, longer patient waiting times, greater exposure to ionizing radiation, and decreased ER flow and efficiency. When evaluating for possible elevation in intracranial pressure, it has been shown that optic nerve sheath diameter (ONSD) measurements correlate with elevated intracranial pressures. This study aims to determine if ultrasonography of the eye can by used to effectively screen patients complaining with headache to determine life-threatening increased intracranial pressure.
Methods: Patients who presented with headache at the emergency room of St. Luke’s Medical Center were recruited. Ultrasound of the eye was done to identify the presence of papilledema and measure the optic nerve sheath diameter. Comparison was done with cranial CT scan or MRI to detect the presence of pathology.
Results: A total of 41 patients were enrolled in the study. Thirteen patients showed increased optic nerve sheathe diameter while only 6 showed intracranial pathology confirmed by imaging. Ocular ultrasound had a 75% Specificity, 50% Sensitivity, 46% positive predictive value and 78% negative predictive value.
Conclusion: Ocular ultrasound is an adequate screening examination to detect increased optic nerve sheath diameter correlated with increased intracranial pressure.