Should Lumbar Puncture Be Required to Diagnose Every Patient With Idiopathic Intracranial Hypertension?

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.

Transorbital sonography in idiopathic intracranial hypertension: Single-center study, systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transorbital sonography (TOS) provides a noninvasive tool to detect intracranial pressure by assessing optic nerve sheath diameter (ONSD) and optic disc elevation (ODE). The utility of TOS in the diagnosis of idiopathic intracranial hypertension (IIH) has been increasingly recognized.

METHODS

A single-center case-control study sought to compare TOS-acquired ONSD and ODE among IIH-cases versus patients with other neurological diseases (controls). Furthermore, a systematic review and meta-analysis was conducted to present pooled mean differences and diagnostic measures of ONSD and ODE between IIH-cases and controls.

RESULTS

In the single-center study, consisting of 31 IIH-cases and 34 sex- and age-matched controls, ONSD values were higher among IIH-cases than controls (p<.001), while ODE was more prevalent in cases (65% vs. 15%; p<.001). The receiver-operating characteristic (ROC)-curve analysis revealed that the optimal cutoff value of ONSD for predicting IIH was 5.15 mm, with an area under the curve (AUC) of 0.914 (95% confidence interval [CI]: 0.861-0.967) and sensitivity and specificity values of 85% and 90%, respectively. In a meta-analysis of 14 included studies with 415 IIH-cases, ONSD and ODE values were higher in IIH-cases than controls (mean difference in ONSD 1.20 mm; 95% CI: 0.96-1.44 mm and in ODE 0.3 mm; 95% CI: 0.33-0.67 mm). With regard to ONSD, pooled sensitivity, specificity, and diagnostic odds ratio were calculated at 85.5% (95% CI: 77.9-90.8%), 90.7% (95% CI: 84.6-94.5%), and 57.394 (95% CI: 24.597-133.924), respectively. The AUC in summary ROC-curve analysis was 0.878 (95% CI: 0.858-0.899) with an optimal cutoff point of 5.0 mm.

CONCLUSIONS

TOS has a high diagnostic utility for the noninvasive diagnosis of IIH and may deserve wider implementation in everyday clinical practice.

Levonorgestrel intrauterine device use and incident idiopathic intracranial hypertension among commercially insured women

OBJECTIVES

To estimate the hazard of incident idiopathic intracranial hypertension, a potentially blinding condition, among women using levonorgestrel intrauterine devices (LNG-IUD) compared to copper IUD, as conflicting associations have been reported.

STUDY DESIGN

This retrospective, longitudinal cohort study identified women ages 18-45 years in a large care network (January 1, 2001, to December 31, 2015) using LNG-IUD, subcutaneous etonogestrel implant, copper IUD, tubal device/surgery, or hysterectomy. Incident idiopathic intracranial hypertension was defined as the first diagnosis code for after 1 year without any codes and following brain imaging or lumbar puncture. Kaplan-Meier analysis estimated time-dependent probabilities of idiopathic intracranial hypertension at 1 and 5 years after incident contraception use, stratified by type. Cox regression estimated the hazard of idiopathic intracranial hypertension associated with LNG-IUD use compared to copper IUD (primary comparison) after adjusting for sociodemographics and factors associated with idiopathic intracranial hypertension (e.g., obesity) or contraception selection. A sensitivity analysis with propensity score-adjusted models was performed.

RESULTS

Of 268,280 women, 78,175 (29%) used LNG-IUD, 8715 (3%) etonogestrel implant, 20,275 (8%) copper IUD, 108,216 (40%) hysterectomy, 52,899 (20%) tubal device/surgery, and 208 (0.08%) developed idiopathic intracranial hypertension over a mean follow-up of 2.4 ± 2.4 years. Also, 1-/5-year Kaplan-Meier idiopathic intracranial hypertension probabilities were 0.0004/0.0021 for LNG-IUD and 0.0005/0.0006 for copper IUD users. LNG-IUD use did not show significantly different hazard of idiopathic intracranial hypertension compared to copper IUD (adjusted hazard ratio 1.84 [95% CI 0.88, 3.85]). Sensitivity analyses were similar.

CONCLUSIONS

We did not observe a significantly increased hazard of idiopathic intracranial hypertension among women using LNG-IUD compared to copper IUDs.

IMPLICATIONS

The lack of an association between LNG-IUD use and idiopathic intracranial hypertension in this large observational study provides reassurance to women considering initiation or continued use of this highly effective contraceptive method.

Diagnostic performance of neuroimaging in suspected idiopathic intracranial hypertension

The diagnostic utility of neuroradiologic signs associated with idiopathic intracranial hypertension (IIH) for the evaluation of patients presenting with papilloedema remains yet to be elucidated. This multicentre retrospective cohort study assessed consecutive patients presenting with suspected papilloedema to Auckland District Health Board (NZ) and Stanford University Medical Centre (US), between 2005 and 2019, undergoing magnetic resonance imaging and venography (MRI/MRV) or computed tomography and venography (CT/CTV) prior to lumbar puncture assessment for diagnostic suspicion of IIH. Data were collected regarding demographic, clinical, radiologic, and lumbar puncture parameters, and the diagnosis of IIH was determined according to the Friedman criteria for primary pseudotumor cerebri syndrome. A total of 204 participants (174 females; mean ± SD age 29.9 ± 12.2 years) were included, and 156 (76.5%) participants fulfilled the diagnostic criteria for IIH. The presence of any IIH-associated radiologic sign on MRI/MRV demonstrated a sensitivity (95% CI) of 74.8% (65.8%-82.0%) and specificity (95% CI) of 94.7% (82.7%-98.5%), while radiologic signs on CT/CTV exhibited a sensitivity (95% CI) of 61.0% (49.9%-71.2%) and specificity (95% CI) of 100.0% (83.2%-100.0%). In summary, the modest sensitivities of radiologic signs of IIH would support the routine use of lumbar puncture assessment following neuroimaging to secure the diagnosis. However, the high specificities might lend limited support for the judicious deferment of lumbar puncture assessment among typical IIH demographic patients who consent to the inherent small risk of missed pathology, which has been proposed by some clinicians.

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.