Can Lumbar Puncture Be Safely Deferred in Patients With Mild Presumed Idiopathic Intracranial Hypertension?

Differentiating between mild papilledema and pseudopapilledema on fundus photography

OBJECTIVE

True papilledema can be difficult to distinguish from pseudopapilledema, especially if mild. Tele-ophthalmology allows fundus photos of suspected disc edema to be sent remotely to neuro-ophthalmologists for their expert interpretation. This study evaluated the ability of neuro-ophthalmologists to discriminate papilledema from pseudopapilledema in mild cases of optic disc swelling based on fundus photographs, with and without patient information.

METHODS

Fundus photographs from 55 patients referred to two neuro-ophthalmology centers for suspicion of papilledema with mild optic disc swelling were reviewed. Patients with normal visual function and no evidence of secondary intracranial hypertension were included. Strict definitions were used to define papilledema and pseudopapilledema. Three neuro-ophthalmologists rated fundus photos as either papilledema or pseudopapilledema before and after the provision of patient age, sex, body mass index (BMI), and visual acuity.

RESULTS

Twenty-nine patients fulfilled criteria for the papilledema group and 26 in the pseudopapilledema group. Fifty-one subjects were female, average age was 32.8 years, and average BMI was 30.9 kg/m2. When photos were rated in isolation, overall accuracy was 59.4 % and inter-rater reliability was poor (k = 0.052). The true positive rate was 56.3 %, true negative rate 62.8 %, false positive rate 37.2 %, and false negative rate 43.7 %. Providing patient information improved overall accuracy to 64.2 % and inter-rater reliability to k = 0.37.

CONCLUSIONS

It is difficult even for neuro-ophthalmologists to correctly distinguish mild papilledema from pseudopapilledema based on fundus photographs alone. Providing basic patient information in telemedicine referrals can improve clinical appraisal and guide the invasiveness of investigations.

Swelling of Atrophic Optic Discs in Idiopathic Intracranial Hypertension

BACKGROUND

Monitoring patients with idiopathic intracranial hypertension (IIH) and optic atrophy may be difficult as papilledema may not be appreciable on ophthalmoscopy. This retrospective chart review evaluated whether papilledema recurrence can be detected in this population using optical coherence tomography (OCT).

METHODS

Serial clinical assessments, ophthalmoscopy, and peripapillary OCT were reviewed in a cohort of patients with IIH and optic atrophy. Atrophy was defined as moderate if average peripapillary retinal nerve fiber layer (pRNFL) thickness was ≤80 μm and severe if average pRNFL thickness was ≤60 μm on at least 2 consecutive high-quality OCT scans. Based on the upper tolerance limit of test-retest variability, mean pRNFL elevation of ≥6 μm with subsequent decrease to baseline thickness was considered papilledema.

RESULTS

In a cohort of 165 patients with IIH, 32 eyes of 20 patients and 22 eyes of 12 patients demonstrated moderate and severe optic atrophy, respectively. Over a median follow-up of 198.5 weeks (range, 14.0-428.9), 63.3% (19 of 30) of patients had at least 1 episode of relapse, and 50.0% (15 of 30) had at least 1 episode of papilledema. There was a total of 36 relapse episodes, of which 7 occurred in patients with clinical signs and symptoms but no OCT evidence of relapse, 12 occurred in patients with OCT changes but no clinical signs and symptoms of relapse, and 17 occurred in patients with both clinical and OCT evidence to support relapse. The median percent pRNFL increase in the latter 2 groups was 13.7% (range, 7.5-111.8), and 7 eyes (13.0%) of 5 patients (16.7%) showed thickening greater than 20.0% from baseline. The rate, magnitude, and concordance of pRNFL swelling were similar between moderately vs severely atrophic eyes.

CONCLUSIONS

Papilledema recurrence can be detected in atrophic optic discs using OCT. All patients with atrophic IIH should be longitudinally monitored with pRNFL measurement. Concurrence of other relapse-suggestive features should prompt further evaluation.

Current and emerging diagnostic and management approaches for idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is characterized by raised intracranial pressure that triggers disabling headaches and can cause permanent visual loss. There is an increased incidence and prevalence of the condition linked to location-specific obesity rates. There are no licensed treatments for the condition. The majority of approaches to managing the disease prioritize resolution of papilledema. However, evidence is emerging that idiopathic intracranial hypertension is a systemic metabolic disease.

AREAS COVERED

The aim of this review is to present the emerging pathophysiology evidence which is leading to novel targeted therapeutics. The diagnostic pathway is outlined. The current and potential management approaches for idiopathic intracranial hypertension are also discussed.

EXPERT OPINION

Idiopathic intracranial hypertension is a condition with metabolic dysregulation with systemic manifestations that are present over and above what can be expl.ained by obesity alone. While most of the current management of this condition focuses on the eyes, future management needs to address the disabling headaches and the systemic risks of preeclampsia, gestational diabetes, and major cardiovascular events.

Papilledema: A review of etiology, pathophysiology, diagnosis, and management

Papilledema is optic nerve head edema secondary to raised intracranial pressure (ICP). It is distinct from other causes of optic disk edema in that visual function is usually normal in the acute phase. Papilledema is caused by transmission of elevated ICP to the subarachnoid space surrounding the optic nerve that hinders axoplasmic transport within ganglion cell axons. There is ongoing controversy as to whether axoplasmic flow stasis is produced by physical compression of axons or microvascular ischemia. The most common cause of papilledema, especially in patients under the age of 50, is idiopathic intracranial hypertension (IIH); however, conditions that decrease cerebrospinal fluid (CSF) outflow by either causing CSF derangements or mechanically blocking CSF outflow channels, and rarely conditions that increase CSF production, can be the culprit. When papilledema is suspected clinically, blood pressure should be measured, and pseudopapilledema should be ruled out. Magnetic resonance imaging of the brain and orbits with venography sequences is the preferred neuroimaging modality that should be performed next to look for indirect imaging signs of increased ICP and to rule out nonidiopathic causes. Lumbar puncture with measurement of opening pressure and evaluation of CSF composition should then be performed. In patients not in a typical demographic group for IIH, further investigations should be conducted to assess for underlying causes of increased ICP. Magnetic resonance imaging of the neck and spine, magnetic resonance angiography of the brain, computed tomography of the chest, complete blood count, and creatinine testing should be able to identify most secondary causes of intracranial hypertension. Treatment for patients with papilledema should be targeted toward the underlying etiology. Most patients with IIH respond to weight loss and oral acetazolamide. For patients with decreased central acuity and constricted visual fields at presentation, as well as patients who do not respond to treatment with acetazolamide, surgical treatments should be considered, with ventriculoperitoneal shunting being the typical procedure of choice.