Prevalence and utility of overnight pulse oximetry as a screening tool for obstructive sleep apnoea in newly diagnosed idiopathic intracranial hypertension

Investigation of Cranial Bone Changes Indicative of Increased Intracranial Pressure in Diverse Phenotypes of Craniosynostosis

Background

Despite the clinical importance of identifying increased intracranial pressure (IIP) in children with craniosynostosis (CS), its presence is often uncertain due to limited utilization of invasive measurement methods, inconclusive clinical evaluations, and its variability depending on the CS phenotype. Hence, prevalence reports are highly variable. We previously developed a computational method to identify pediatric chronic IIP of diverse etiology based on subtle cranial thickness and density anomalies quantified from computed tomography (CT) scans. In this study, we evaluate cranial signs of IIP in a large dataset of presurgical CT scans of patients with diverse phenotypes of CS and its prevalence.

Methods

We quantified local cranial thickness and density in the CT scans of 417 patients with diverse phenotypes of CS (age 0-2 y). We used a normative reference of cranial development to quantify cranial bone anomalies in each phenotypic group and compared them with 48 patients with chronic IIP unrelated to CS. We then studied the risk of IIP and its prevalence in each phenotypic group of CS.

Results

Patients with CS presented significant calvarial thickening and bone density decrease compared with normative patients (P < 0.001). Similar findings were found in patients with chronic IIP unrelated to CS (P > 0.23). Presurgical signs of IIP were more prevalent in patients with Apert syndrome (>74% patients) and nonsyndromic patients with coronal involvement (>30%) compared with other phenotypes (>18%).

Conclusions

Computational evaluation of routinely acquired presurgical CT scans can potentially support the evaluation of IIP in patients with CS.

A Systematic Review of Sleep Disturbance in Idiopathic Intracranial Hypertension

Purpose of Review

Sleep disturbances, particularly obstructive sleep apnea (OSA), may have a significant impact on the outcomes of patients with idiopathic intracranial hypertension (IIH). We conducted a PRISMA-compliant systematic literature review to study sleep disturbance in adult patients with IIH.

Recent Findings

The current literature on the relationship between IIH and sleep is quite limited. Research has found that sleep disturbances are associated with lower quality of life and may worsen several symptoms associated with IIH, such as headache, cognitive deficits, and neuropsychiatric issues.

Summary

OSA was more prevalent in patients with IIH than in healthy controls. Several studies found that OSA was associated with worse IIH symptoms and treatment of OSA helped improve these parameters. Limitations included available literature and heterogeneity in sleep metrics and OSA diagnostic criteria between studies. Overall, further study of sleep disturbances in patients with IIH may encourage earlier screening, improved treatment options, and long-term improvements in quality of life.

Obstructive sleep apnea in those with idiopathic intracranial hypertension undergoing diagnostic in-laboratory polysomnography

RATIONALE

The association of obstructive sleep apnea (OSA) with idiopathic intracranial hypertension (IIH) remains unclear, and few studies have used objective in-laboratory polysomnography (PSG) data. Thus, we used PSG data to examine the: 1) association between OSA, and its severity, with IIH and 2) sex differences in OSA severity in those with and without IIH.

METHODS

We retrospectively analyzed diagnostic PSG data from January 2015 to August 2023 for patients who were diagnosed with IIH by a neuro-ophthalmologist using the modified Dandy criteria. We selected three age, sex, and body mass index (BMI) matched controls for each IIH patient. We examined potential associations of IIH with OSA using regression. Sex differences were analyzed using ANOVA.

RESULTS

Of 3482 patients who underwent PSG, we analyzed 78 IIH patients (16 males) and 234 matched controls (48 males). Five (6.4 %) IIH and 39 (16.7 %) control patients had OSA, defined as AHI≥15. After adjusting for age, sex, BMI, and comorbidities, IIH was negatively associated with the presence of OSA (OR 0.29, 95%CI 0.10-0.87, p = 0.03). However, models that adjusted for acetazolamide use, with or without comorbidities, showed no significant relationship with OSA (OR 0.31, p = 0.20). Males with IIH had a significantly higher age (p = 0.020), OSA severity (p = 0.032), and arousal index (p = 0.046) compared to females with IIH.

CONCLUSIONS

IIH treated with acetazolamide was not an independent risk factor for OSA presence or severity. The presence of IIH treated with acetazolamide likely does not warrant routine screening for OSA, but related risk factors may identify appropriate patients.

Neuro-ophthalmic features of patients with spontaneous cerebrospinal fluid leaks

Background

Increased intracranial pressure is a potential cause of spontaneous cerebrospinal fluid (sCSF) leak. Associated neuro-ophthalmic features have not been well studied, particularly relationships with idiopathic intracranial hypertension (IIH). We hypothesized that neuro-ophthalmic features routinely used in evaluations for IIH can be useful in the investigation of a causal relationship between IIH and sCSF leak. We reviewed the neuro-ophthalmic examination and office-based ophthalmic imaging data of all consecutive patients with sCSF leaks and at least one repair to investigate the clinical and neuro-ophthalmic features of increased intracranial pressure.

Methods

We conducted a retrospective longitudinal study at a single institution by querying the electronic medical record system for CSF leak Current Procedural Terminology (CPT) codes (G96.00 and G96.01) from June 1, 2019, to July 31, 2022. For patients with a confirmed diagnosis of sCSF leak, demographic information, eye examination results, and ophthalmic imaging details for both eyes were collected.

Results

A total of 189 patients with CSF leaks were identified through CPT coding; 159 had iatrogenic or traumatic CSF leaks, and 30 individuals (3 male, 27 female) had confirmed sCSF leaks. The mean age of patients with sCSF leaks was 46 years (range: 29 - 81), with a mean body mass index of 35.2 kg/m2 (range: 18.2 - 54.1). Only 11 of 30 underwent eye examinations (8 before surgical repair and 10 after). The mean pre-repair and post-repair best-corrected visual acuity were 20/30 (range: 20/20 - 20/55) and 20/25 (range: 20/20 - 20/40), respectively (P = 0.188). The mean retinal nerve fiber layer thickness was 99 µm (range: 96 - 104) pre-repair and 97 µm (range: 84 - 103) post-repair (P = 0.195). The mean ganglion cell complex thickness was 84 µm (range: 72 - 94) pre-repair and 82 µm (range: 71 - 94) post-repair (P = 0.500). Humphrey visual field average mean deviation was -5.1 (range: -12.4 - -1.8) pre-repair and -1.0 (range: -10.1 - 2.1) post-repair (P = 0.063).

Conclusions

Serial neuro-ophthalmic examinations are recommended for patients with sCSF leaks to screen for signs of current or prior increased intracranial pressure. Larger studies are required to clarify the longitudinal changes in neuro-ophthalmic features, to investigate the incidence of IIH in cases of sCSF leak development or recurrence after surgical repair, and to explore potential causal relationships to guide post-repair management and prevent recurrent leaks. A multicenter consortium is also suggested to develop a standard clinical protocol for comprehensive management of sCSF leaks.

Idiopathic intracranial hypertension: a step change in understanding the disease mechanisms

The understanding of idiopathic intracranial hypertension (IIH) has evolved over the past few years. Previously, IIH was considered a disease exclusively affecting the neuro-ophthalmic axis, characterized by raised intracranial pressure, headache and papilloedema, and resulting in the risk of severe and permanent visual loss and life-changing disabling headaches. Recent advances have begun to redefine IIH as a probable metabolic disease involving a range of systemic manifestations. More than 95% of individuals affected by the disease are women of reproductive age with obesity. The incidence is rapidly rising and parallels the escalating worldwide obesity rates. Contemporary insights identify associations with insulin resistance, type 2 diabetes and a twofold increased risk of cardiovascular disease in excess of that driven by obesity alone. Adipose distribution in people with IIH, like that in other metabolic diseases, is preferentially centripetal and is associated with changes in intracranial pressure. Evidence now demonstrates adipose tissue dysfunction in people with IIH, involving transcriptional and metabolic priming for lipogenesis and weight gain. Hormonal perturbations are also observed, including a unique phenotype of androgen excess that promotes cerebrospinal fluid secretion. Knowledge of these additional disease features is driving research into novel therapeutic targets and altering the approach to multidisciplinary care.

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.