Is initial optic nerve sheath diameter prognostic of specific head injury in emergency departments?

Efficacy of bedside optic nerve sheath diameter measurement in differentiating provoked seizure from unprovoked seizure in the emergency department

BACKGROUND

Emergency departments (EDs) are typically the first medical contact for seizure patients, and early diagnosis and treatment is primarily the responsibility of emergency physicians.

OBJECTIVES

Demonstrate the efficacy of bedside ocular ultrasonography for optic nerve sheath diameter (ONSD) measurement in differentiating provoked seizure from unprovoked seizure in the ED.

DESIGN

Prospective observational study SETTINGS: Tertiary care hospital PATIENTS AND METHODS: Patients presenting to the ED with seizure were divided into two groups according to medical history, physical examination, laboratory results, cranial computed tomography findings and electroencephalography results. Patients with seizures that did not have a specific cause (unprovoked) were compared with patients who had seizures caused by underlying pathology (provoked). The measurement of the ONSD was taken at the bedside within 30 minutes of arrival. The study compared the ONSD values, age, sex, type of seizure, and Glasgow Coma Score between the two groups.

MAIN OUTCOME MEASURE

Efficacy of ONSD to distinguish between provoked and unprovoked seizures.

SAMPLE SIZE

210 patients RESULTS: One hundred and fourteen (54.3%) patients were in the provoked seizure group and 96 (45.7%) were in the unprovoked seizure group. The ONSD measurements were significantly higher in the provoked seizure group compared with the unprovoked seizure group (median 6.1 mm vs. 5.2 mm, P<.001). The cut-off value of ONSD higher than 5.61 was significantly associated with the prediction of the provoked seizure (P<.001). The area under the curve value was 0.882 (95% CI: 0.830-0.922) with a sensitivity of 86.5 and specificity of 78.9%.

CONCLUSIONS

Bedside ONSD measurement by means of ocular ultrasound is an effective method for differentiating provoked seizure from unprovoked seizure.

LIMITATIONS

Statistical significance of age on ONSD and exclusion of pediatric patients.

CONFLICT OF INTEREST

None.

Serial Optic Nerve Sheath Diameter via Radiographic Imaging: Correlation With ICP and Outcomes

Objective

Evaluation of optic nerve sheath diameter (ONSD) is a suggested correlation of intracranial pressure (ICP) and potential predictor of outcome after neurologic injury. Studies have evaluated sonographic measurement of ONSD; however, clinical limitations to this approach persist. Evaluation of ONSD measurements via routine brain CT imaging is less studied but offers potential for detection of increased ICP in the absence of invasive monitoring. Previous studies have used cross-sectional approaches to ONSD measurements via CT scan among patients with traumatic brain injury (TBI). No studies have evaluated serial correlations between CT ONSD measurements and ICP throughout hospitalization and across diagnosis types. The objective of this study was to investigate correlations between ONSD via serial CT imaging, ICP, and outcome at discharge among patients with neurologic injury.

Methods

This is a retrospective cohort study of all adult patients admitted during a 12-month period with acute neurologic injury requiring ICP monitoring and critical care admission.

Results

N = 48. There was a strong, positive correlation between right/left ONSD across time points (r = 0.7-9, p < 0.001), suggesting a consistent bilateral response. Correlations were strongest between initial inpatient CT scan ONSD readings and ICP (r = 0.5, p < 0.05), but decreased over time. Patients with increased ICP across all diagnosis types experienced higher ONSD values on presentation to the emergency department (ED) and throughout hospitalization (range 5.7-6.4 mm, p < 0.05).

Conclusions

Findings contribute to the utility of CT ONSD measurements as a potential indicator of increased ICP. Measurement of ONSD during serial CT brain imaging may inform clinical decisions regarding need for more invasive monitoring after neurologic injury.

The association between intracranial pressure and optic nerve sheath diameter on patients with head trauma

BACKGROUND

Although intracranial pressure (ICP) monitoring is the gold standard method for measuring intracranial pressure after traumatic brain injury, optic nerve sheath diameter (ONSD) measurement with ultrasound (US) is also used in the evaluation of ICP.

OBJECTIVE

To investigate the association between a series of OSND measurements by US and changes in clinical presentation of the patient.

METHODS

Prospective study including 162 patients with traumatic brain injury. Age, sex, cerebral CT findings, ONSD levels by US at minutes 0, 60, and 120, Glasgow Coma Scale (GCS) within same period, change of consciousness, treatment, and mortality data were reviewed. The association of ONSD levels with GCS, change of consciousness, treatment, and mortality was evaluated.

RESULTS

There was no difference in ONSD changes in the patients' sample within the period (p=0.326). ONSD significantly increased in patients who died (p<0.001), but not in those who survived (p=0.938). There was no significant change in ONSD of the patients who received anti-edema therapy (p=801), but significantly increased ONSD values were found in those who received anti-edema therapy (p=0.03). Patients without change of consciousness did not have any significant change in ONSD (p=0.672), but ONSD values increased in patients who consciousness became worse, and decreased in those who presented a recovery (respectively, p<0.001, p=0.002). A negative correlation was detected between ONSD values and GSC values measured at primary, secondary, and tertiary time periods (for all p<0.001).

CONCLUSIONS

ONSD follow-up may be useful to monitor ICP increase in patients with acute traumatic brain injury.

Determination of ventriculoperitoneal shunt dysfunction using optic nerve sheath diameter measurement on CT scan in pediatric patients with hydrocephalus

PURPOSE

We aimed to evaluate whether optic nerve sheath diameter (ONSD) measurement by computed tomography (CT) can be a diagnostic criteria for the detection of ventriculoperitoneal shunt dysfunction among children whose fontanels are still open.

METHODS

Patients with a ventriculoperitoneal shunt who were currently showing clinical and radiological signs of acute hydrocephalus depending on the shunt dysfunction were included in this study. The study was designed to compare the preoperative and postoperative ONSDs of three groups of patients divided according to their ages: group 1, patients aged < 4 months; group 2, patients aged 4-18 months; and group 3, patients aged > 18 months.

RESULTS

We included 138 patients (mean age, 35.18 ± 51.01 months). Among the patients, 46.4% were females and 53.6% were males. ONSD measurements in the preoperative period were < 2.86 ± 0.59 in group 1, 3.93 ± 0.82 in group 2, and 5.40 ± 0.81 in group 3 and those in the postoperative period were 2.02 ± 0.38 in group 1, 2.72 ± 0.62 in group 2, and 3.64 ± 0.81 in group 3. Right, left, and mean ONSDs increased significantly in the three groups and were found to be statistically significant.

CONCLUSION

ONSD measurement in CT has been evaluated as an appropriate finding that can be used especially in acute hydrocephalus, when clinical and radiological findings are not diagnostic.