Emergency Medicine Fri 17 July 2020 To determine by ultrasound the optic nerve sheath diameter in pediatric patient with increased intracranial pressure compared with control group.
Researcher : Kappagantu vignan
Research Guide : Bhoi sanjeev
Institution Name : All india institute of medical sciences new delhi


Background and Aim: Increased intracranial pressure is a well-known cause of morbidity in pediatric age group. There are many ways to measure the raise in intracranial pressure like CT scan, MRI, ophthalmoscopy showing papilledema, direct monitoring by placing a transducer probe in the subarachnoid space and optic nerve sheath diameter measurement by ultrasound. Optic nerve sheath diameter measurement by ultrasound is very feasible as a means of measurement of intracranial pressure in emergency department. This study’s aim was to observe the optic nerve sheath diameter in pediatric age group 3 – 18 years using point – of – care ultrasound and correlate the observations with those showing increased intracranial pressure by CT scan. Additionally, we tried to correlate the optic nerve sheath diameter with CT scan by age, gender and cause of raise. Methodology: Ours is a prospective analytical study done between April 2018 and August 2019, which included 125 study subjects, 40 subjects who were not having raised intracranial pressure when clinically examined (external controls), 85 who showed clinical features of raised intracranial pressure. Their demographic profile, clinical examination and ultrasound findings of optic nerve sheath diameter was taken. CT scan was performed on those 85 patients who showed clinical findings of raised intracranial pressure. Of all those patients, 43 had raised intracranial pressure (cases) and 42 had normal intracranial pressure (disease controls). All these findings were later statistically analyzed. Results: The mean optic nerve sheath diameter in external control group was 4.8 ± 0.3 mm, while in disease control group was 4.9 ± 0.5 mm and case group 5.5 ± 0.6 mm. receiver operator characteristic analysis revealed that the optimal cutoff of optic nerve sheath diameter for raised intracranial pressure was ≥ 5.0 mm with a sensitivity of 86.1 % and specificity of 71.7% which was similar to many other studies conducted worldwide. A similar cutoff of ≥5.0 mm was seen in age group of 3 – 12 years. However, a slightly higher cutoff was seen in age group of 3 – 18 years at 5.2 mm. But the sample size was found to be insufficient for analysis in that age group. It was also found that there was no difference in optic nerve sheath diameter by gender. The sample size was insufficient to derive cause wise cutoffs. Additionally, some findings like papilledema by ophthalmoscopy, crescent sign and optic disc elevation were noted. Papilledema had a sensitivity and specificity of 70.0% and 76.2% respectively, while crescent sign had sensitivity of 72.1% and specificity of 80.9%. optic disc elevation had sensitivity and specificity of 60.5% and 83.3%. By combining all the three ultrasound features, we found a sensitivity of 72.1 % and specificity of 92.1%. Conclusion:Through our study, we have found that the optic nerve sheath diameter by ultrasound is a good method of identifying raised intracranial pressure. The optic nerve sheath diameter cutoff value for identifying raised intracranial pressure was set at ≥5 mm. As shown by the results, there is no change in the cutoff with age and gender. Additional findings like crescent sign and optic disc elevation were also found to be having a good correlation to findings of raised intracranial pressure by computerized tomography.

DOI: 1595004156   Year of publication: 2019

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