Unilateral Isolated Paucisymptomatic Optic Disc Edema

Diagnosis of Optic Disc Oedema: Fundus Features, Ocular Imaging Findings, and Artificial Intelligence

Optic disc swelling is a manifestation of a broad range of processes affecting the optic nerve head and/or the anterior segment of the optic nerve. Accurately diagnosing optic disc oedema, grading its severity, and recognising its cause, is crucial in order to treat patients in a timely manner and limit vision loss. Some ocular fundus features, in light of a patient's history and visual symptoms, may suggest a specific mechanism or aetiology of the visible disc oedema, but current criteria can at most enable an educated guess as to the most likely cause. In many cases only the clinical evolution and ancillary testing can inform the exact diagnosis. The development of ocular fundus imaging, including colour fundus photography, fluorescein angiography, optical coherence tomography, and multimodal imaging, has provided assistance in quantifying swelling, distinguishing true optic disc oedema from pseudo-optic disc oedema, and differentiating among the numerous causes of acute optic disc oedema. However, the diagnosis of disc oedema is often delayed or not made in busy emergency departments and outpatient neurology clinics. Indeed, most non-eye care providers are not able to accurately perform ocular fundus examination, increasing the risk of diagnostic errors in acute neurological settings. The implementation of non-mydriatic fundus photography and artificial intelligence technology in the diagnostic process addresses these important gaps in clinical practice.

Expanding the clinical spectrum of idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH.

RECENT FINDINGS

Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association.

SUMMARY

Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

Incipient Non-Arteritic Anterior Ischemic Optic Neuropathy in a Patient with Metastatic Small-Cell Lung Cancer

A 70-year-old woman with metastatic small-cell lung cancer was referred for isolated left optic disc edema that was incidentally discovered. She had normal visual function, and dilated fundus examination revealed a small, cupless optic nerve in the right eye and moderate optic disc edema in the left eye. Magnetic resonance imaging (MRI) of the orbits with contrast was normal, and MRI brain and magnetic resonance venography were normal without signs of raised intracranial pressure. Lumbar puncture showed a normal opening pressure and normal cerebrospinal fluid contents. A diagnosis of incipient non-arteritic anterior ischemic optic neuropathy (NAION) was made, and the optic disc edema resolved after 4 months. Incipient NAION is an uncommon cause of unilateral optic disc edema with preserved visual function and is a diagnosis of exclusion. In diagnosing incipient NAION, other causes of optic disc edema must first be ruled out. These alternative causes include papilledema, optic nerve sheath meningioma or other orbital masses, and vitreopapillary traction. Incipient NAION is thought to be caused by subclinical ischemia. This case indicates that incipient NAION may also occur in patients with metastatic cancer and is possibly related to their hypercoagulable state. Although there is no treatment once vision loss develops, the optimization of risk factors may prevent the progression of incipient NAION to classic NAION.

Bilateral optic disc edema with preserved visual function not related to papilledema

Bilateral optic disc edema (ODE) with preserved visual function is typically a result of papilledema, but the causes of this finding in the absence of raised intracranial pressure have not been systematically evaluated. The goal of this study was to determine the causes of bilateral ODE with preserved visual function not related to intracranial hypertension to help in developing a differential diagnosis for this finding. We retrospectively reviewed 221 consecutive patients presenting to a tertiary neuro-ophthalmology practice over a period of 2 years. Four patients met the inclusion criteria with a mean age of 53 years (range 43 to 63), 2 patients were men and 2 were women. The final diagnoses were bilateral optic perineuritis secondary to p-ANCA vasculitis, bilateral incipient non-arteritic anterior ischemic optic neuropathy (NAION), hypertensive emergency, and intermediate uveitis. The patient with NAION developed an inferior altitudinal defect 4 months after presentation, but all other patients maintained normal visual function. The ODE resolved in all cases at a mean follow-up of 4.5 months (range 3 to 6 months). Optic disc edema with preserved visual function may not be related to papilledema, and this series indicates that optic perineuritis, incipient NAION, hypertensive emergency, and intermediate uveitis be considered in the differential diagnosis of these cases.