Diagnostic Accuracy of Ocular Ultrasonography in Identifying Raised Intracranial Pressure among Pediatric Population

INTRODUCTION

Role of CT scan, MRI, ophthalmoscopy, direct monitoring by a transducer probe in identifying raised intracranial pressure (ICP) in emergency department is limited. There are few studies correlating elevated optic nerve sheath diameter (ONSD) measured by point of care ultrasound (POCUS) with raised ICP in pediatrics emergencies. We studied the diagnostic accuracy of ONSD, crescent sign, and optic disc elevation in identifying increased ICP in pediatrics.

METHODS

Prospective observational study was done between April 2018 and August 2019 after ethics approval. Out of 125 subjects, 40 patients without clinical features of raised ICP were recruited as external controls and 85 with clinical features of raised ICP as study subjects. Their demographic profile, clinical examination, and ocular ultrasound findings were noted. This was followed by CT scan. Out of 85 patients, 43 had raised ICP (cases) and 42 had normal ICP (disease controls). Diagnostic accuracy of ONSD in identifying raised ICP was evaluated using STATA.

RESULTS

The mean ONSD in case group was 5.5 ± 0.6 mm, 4.9 ± 0.5 mm in disease control group and external control group was 4.8 ± 0.3 mm. Cut-off of ONSD for raised ICP at ≥4.5 mm had a sensitivity and specificity of 97.67% and 10.98%, while ≥5.0 mm showed a sensitivity and specificity of 86.05% and 71.95%. Crescent sign and optic disc elevation had good correlation with increased ICP.

CONCLUSION

ONSD ≥5 mm by POCUS identified raised ICP in pediatric population. Crescent sign and optic disc elevation may function as additional POCUS signs in identifying raised ICP.

[Atraumatic and aseptic osteonecrosis of large joints]

Subchondral osteonecrosis of large weight-bearing joints (hip and knee joints) represents a severe and joint-threatening disease. Apart from idiopathic forms, glucocorticoid medication and alcohol abuse have been identified as major causative factors for atraumatic osteonecrosis. In addition to direct cytotoxic factors, a critically reduced perfusion of the subchondral osseous space will eventually lead to bone marrow ischemia and osseous necrosis. Magnetic resonance imaging (MRI) is capable of visualizing a reactive border-like zone in this early, already irreversible and often asymptomatic stage I according to the Association of Research Circulation Osseous (ARCO) staging system. Later in the course, osteonecrosis progresses to form serpiginous sclerotic lines, enclosing the necrotic bone area (stage II ARCO). Repair mechanisms of osteonecrosis are mostly unsuccessful and depending on the size of the osteonecrosis result in biomechanical failure and ultimately subchondral insufficiency fractures (crescent sign), thus marking the transition to stage III ARCO (joint surface collapse).

Accuracy of crescent sign on ocular ultrasound in diagnosing papilledema

AIM

To study the usefulness of orbital ultrasonography in the diagnosis of papilledema.

METHODS

Fifty patients who were referred to the neurophthalmology clinic and clinically suspected to have papilledema were selected. Thorough, clinical examination with slitlamp biomicroscopy and visual acuity assessment was done. These patients underwent ultrasonography to demonstrate the crescent sign. The patients were further evaluated with the neurologist and magnetic resonance imaging (MRI) thus confirming the diagnosis of papilledema. The results of our ultrasonographic evaluation were correlated with final diagnosis after thorough clinical evaluation, imaging and the neurologist’s opinion.

RESULTS

Out of 50 patients diagnosed having papilledema on MRI, 46 (92%) showed crescent sign on B scan ultrasonography. Headache was most common presenting complaint in 47 (94%) and idiopathic intracranial hypertension was most common underlying cause of papilledema in 30 (60%) cases.

CONCLUSION

“Crescent sign” seen on ultrasonography is a sensitive tool for diagnosis of papilledema. It is cost effective, less cumbersome and effective tool to differentiate between papilledema and pseudo papilledema before subjecting the patients to costly investigations like MRI. A positive crescent sign should always be followed by MRI to find out the cause of papilledema.