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- Published on: 26 April 2020
- Published on: 23 February 2018
- Published on: 26 April 2020Comment on: Detecting optic nerve head swelling on ultrasound and optical coherence tomography in children and young people.
Optic disc drusen pose a diagnostic challenge when trying to differentiate between papilloedema and pseudopapilloedema.1 Dahlman-Noor et al highlight the importance of a structured history when evaluating children with optic nerve head (ONH) swelling. The authors recommend a future study to explore the diagnostic accuracy of an algorithm published by the Royal College of Paediatrics and Child Health (RCPCH) which details key features of the history (e.g. headache, vomiting, visual symptoms) that should trigger neuroimaging.2
As part of a prospective study of children referred to our regional paediatric ophthalmology service for assessment for ONH swelling, we implemented this algorithm. 122 children under 16 years of age were assessed from 1st January to 31st December 2018. 93% (113/122) had optic disc drusen, 4% (5/122) had normal optic discs, and 3% (4/122) had papilloedema. Two cases of papilloedema were caused by idiopathic intracranial hypertension (IIH) and two by venous sinus thrombosis.
Of the 118 patients with drusen or normal discs, only one fulfilled the RCPCH criteria for neuroimaging: a 14-year-old girl with persistent headaches and vomiting. Neuroimaging and lumbar puncture were unremarkable, and her symptoms were ultimately attributed to migraine.
For the four patients with papilloedema, the algorithm-derived questions would have triggered neuroimaging in three cases. This yields a specificity of 99% but a sensitivity of only...
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None declared. - Published on: 23 February 2018Optic nerve head swelling on ultrasound and optical coherence tomography in children
Dear Editor,
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we read with great interest the article by Dahlmann-Noor et al. concerning the possibility to detect optic nerve (ON) head swelling on ultrasound and OCT. 1
They reported 61 children , investigated for ‘suspicious discs’ that underwent both US and OCT. Among these only 3 children had intracranial hypertension (IHT) but all of them were diagnosed as having drusen on US; even the three children with IHT had ‘small linear’ drusen.
We would like to comment on small linear drusen that seem to have been undetected by OCT. This is very unlikely. Much care must be taken to diagnose linear drusen with ultrasound because this image could be an artifact due to the strong echoes coming from a surface where the sound beam is perpendicular .
Measuring optic nerve sheath diameter (ONSD) with B-scan has recently become popular, but there is not a global agreement on how to perform such a measurement as some authors suggest performing axial measurements, some others coronal axis measurements.3-5 Furthermore to establish a cutoff between normal and increased ONSD can be very challenging due to the so-called blooming effect. This B-scan related effect, that should not be confused with the Doppler related one, is due to the lack of sensitivity standard setting: the ON image obtained with a low sensitivity setting will result in larger ON dimensions compared to the ones provided by the same image, increasing the sensitivity setting.
The authors...Conflict of Interest:
None declared.