CASE 14363 Published on 31.01.2017

A Case of Idiopathic Intracranial Hypertension and Optic Disc Drusen

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Ainkaran Santhirasekaram, MBBS, Department of Radiology, Russell Hall Hospital, Dudley, DY1 2HQ, Akhmid Aziz, MBBS, FRCR, Department of Radiology, Russell Hall Hospital, Dudley, DY1 2HQ

Russell Hall Hospital; Pensnett Road DY12HQ Dudley; Email:ainkaran.santhi@gmail.com
Patient

21 years, female

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CT, MR
Clinical History
A 21-year-old female presented with an acute onset generalized headache and blurred vision. On funduscopic examination, bilateral papilloedema was noted. Her past medical history included idiopathic intracranial hypertension (IHH) diagnosed 5 years ago using the updated modified Dandy criteria [1]. Head MRI 5 years ago was unremarkeable.
Imaging Findings
Upon presentation, she underwent a non-contrast Axial brain CT and venogram, which did not demonstrate an intracranial mass lesion or venous sinus thrombosis. However, her non-contrast CT head demonstrated bilateral hyperdense foci on the optic nerve heads due to calcification (fig 1), consistent with a diagnosis of calcified optic disc drusen. There were no signs of papilloedema on CT. A subsequent MRI was completely unremarkable and demonstrated no signs of idiopathic intracranial hypertension including papilloedema (fig 2). A therapeutic lumbar puncture was also done but interestingly the opening pressures and CSF analysis were normal. Her opening pressure on lumbar puncture 5 years ago when she was diagnosed with IIH was 35cm H2O.
Discussion
ODD arise from an abnormal collection of globules containing mucoproteins and mucopolysaccharides derived from the remnants of the axonal transport system from degenerated retinal ganglion cells [1, 2]. These globules progressively calcify and accumulate in the optic disc [1, 2]. If drusen deposits superficially on the optic disc, it is a simple diagnosis most often found incidentally on funduscopic examination [2-4]. However, it can often bury in the deeper aspect of the optic disc head and can mimic papilloedema leading to misdiagnosis [3-5]. Therefore, ODD is a differential diagnosis to consider in cases of optic disc swelling for radiologists and clinicians particularly in patients with IHH who despite normal opening pressures on lumbar puncture continue to demonstrate apparent papilloedema.
ODD affects 0.3-2% of the population and is usually asymptomatic [1]. While impairment in visual acuity is rare, mild visual field defects can present in up to 50 % of patients [1]. A CT is more sensitive than MRI for detecting calcified drusen [6]. If a negative CT head is noted, a combination of ophthalmic ultrasound, optical coherence tomography and fluorescein angiography which is more sensitive than CT, will confirm a diagnosis of ODD [6]. A firm diagnosis of ODD will prevent unnecessary further investigation of the patient and spare avoidable anxiety. IIH can also present with papilloedema and visual disturbances which raises the question whether the initial presentation 5 years ago, was true papilloedema associated with IHH, ODD mimicking papilloedema or a combination of both. She had no CT head 5 years ago. Interestingly, research has shown a possible causal link between patients with idiopathic intracranial hypertension with papilloedema who developed optic disc drusen [7]. It was shown that, the prevalence of optic disc drusen was ten times higher (p <0.001) in patients who had papilloedema from idiopathic intracranial hypertension than the general population. This suggests papilloedema from idiopathic intracranial hypertensions could trigger the development of optic disc drusen [7]. This case could be a demonstration of those findings.
There is no definitive treatment for ODD but this patient would have regular ophthalmic examinations to assess visual acuity and monitor rare complications such as raised intraocular pressure and choroidal neovascularisation.
In conclusion, this case elegantly demonstrates that ODD is a differential diagnosis to consider for both clinicians and radiologists, in patients who demonstrate apparent optic disc papilloedema despite no evidence of intracranial hypertension.
Differential Diagnosis List
Optic disc drusen on a background of idiopathic intracranial hypertension
Retinoblastoma
Astrocytic Hamartomas
Final Diagnosis
Optic disc drusen on a background of idiopathic intracranial hypertension
Case information
URL: https://www.eurorad.org/case/14363
DOI: 10.1594/EURORAD/CASE.14363
ISSN: 1563-4086
License