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.

Neurovascular Compression in the Anterior Visual Pathway: A Case Series.

A retrospective review of 29 patients with neurovascular compression syndrome (NVCS) involving the anterior visual pathway was conducted. Various patterns of NVCS and visual defects were identified, most commonly involving the optic nerve and internal carotid artery. Most patients were stable, except one with progressive visual field defects. Although mostly asymptomatic, NVCS can rarely cause compressive optic neuropathy. NVCS should be kept in the differential diagnosis of normal tension glaucoma, especially with progressive visual loss despite treatment. Patients with progressive visual loss may require decompression surgery. Non-contrast computed tomography scan may miss NVCS, and magnetic resonance imaging is diagnostic.

Homonymous Retinal Ganglion Cell Layer Atrophy With Asymptomatic Optic Tract Glioma in Neurofibromatosis Type I.

Approximately 20% of patients with Neurofibromatosis type 1 (NF1) develop optic pathway gliomas (OPGs). Not all OPGs in NF1 necessarily become vision compromising and predicting which patients might develop visual decline is difficult at present time. Optical coherence tomography (OCT) has emerged as a useful tool able to directly assess the morphology and thickness of individual retinal layers. The ganglion cell layer (GCL) is composed of the retinal ganglion cells which receive information from photoreceptors via interneurons, while the retinal nerve fiber layer (RNFL) contains the retinal ganglion cell unmyelinated axons that merge to form the optic nerve. Lesions of the anterior visual pathway result in retrograde axonal degeneration from ganglion cell death and ultimately manifest as thinning of the RNFL and/or GCL. In this report we highlight a case of a 38 year-old woman with an NF1 associated left chiasmal and optic tract glioma who had normal visual fields and visual acuity. However, using OCT we demonstrate a homonymous pattern of GCL atrophy that corresponds with her left optic tract glioma. Given this homonymous pattern of atrophy in the GCL and the left optic tract lesion, one would expect a right homonymous hemianopia. To our knowledge this is the first reported case of a homonymous pattern of GCL-IPL atrophy in an adult with an NF1 related OPG involving the optic chiasm and optic tract, but without objective visual field or acuity deficits. This case is important because, mechanistically, it suggests that a necessary threshold of GCL atrophy may be needed before visual concerns can be detected and, secondly, it invites future studies to evaluate whether OCT may serve as a potential screening tool for those with NF1 related OPGs.

An evaluation of genetic causes and environmental risks for bilateral optic atrophy.

PURPOSE: To assess the clinical utility of next-generation sequencing (NGS) for the diagnosis of patients with optic atrophy (OA). DESIGN: Retrospective cohort study. METHODS: 97 patients were referred to the McMaster University Medical Center (Hamilton, Ontario) for evaluation of bilateral OA. All patients were sent for NGS including a 22 nuclear gene panel and/or complete mitochondrial DNA (mtDNA) sequencing. Positive genetic test results and abnormal vibration sensation were compared in patients +/- environmental exposures or a family history. RESULTS: 19/94 (20.2%) had a positive nuclear variant, of which 15/19 (78.9%) were in the OPA1 gene. No positive mtDNA variants were identified. The detection of a positive genetic variant was significantly different in patients who reported excessive ethanol use, but not in patients who smoke (0/19 (0%) vs. 19/78 (24.4%), P = 0.0164 and 4/22 (18.2%) vs. 15/74 (20.3%), P = 0.829, respectively). Patients with a positive family history were more likely to have a positive genetic variant compared to patients with a negative family history (P = 0.0112). There were significantly more excessive drinkers with an abnormal vibration sensation (P = 0.026), and with a similar trend in smokers (P = 0.074). CONCLUSIONS: All positive genetic variants were identified in nuclear genes. We identified a potential independent pathophysiological link between a history of excessive ethanol consumption and bilateral OA. Further investigations should evaluate and identify potential environmental risk factors for OA.

Cortical Ribbon Sign in Acute Hepatic Encephalopathy with Sequential Atrophy.

A 59-year-old man presented with confusion, decreased level of consciousness, and generalized tonic-clonic seizures. He was intubated and promptly stabilized on antiepileptic medications. He was not in status epilepticus. He improved after seizure control, though he remained confused. He was neither acutely intoxicated nor were there any substance withdrawal concerns prior to his presentation. Furthermore, no metabolic, electrolyte, or nutritional perturbations were identified. He did, however, have a history of alcoholic hepatitis and was awaiting a liver transplant, but his blood work did not reveal evidence of fulminant hepatic failure at presentation (international normalized ratio - 1.17, platelet count 161,000/µL, ammonia 18 µmol/L, blood urea nitrogen 4.5 mmol/L, and his liver enzymes were only remarkable for an elevated alkaline phosphatase of 143 U/L).

Rescue bevacizumab following symptomatic pseudoprogression of a tectal glioma post-radiotherapy: a case report and review of the literature.

PURPOSE: Radiation-induced pseudoprogression is a subacute clinical entity that is distinct from radiation necrosis and mimics tumor progression. Bevacizumab is a well-described treatment option for radiation necrosis, but its role in pseudoprogression is not clearly defined. METHODS: We report a case of radiation-induced pseudoprogression rescued with bevacizumab in a 20-year-old man with a biopsy-proven low-grade astrocytoma of the tectum. A review of the literature was also conducted specific to bevacizumab as a treatment for symptomatic pseudoprogression after radiotherapy for CNS tumors. RESULTS: This patient was treated with definitive intensity modulated stereotactic radiotherapy at a total dose of 54 Gy delivered in 30 daily fractions. Six weeks after radiotherapy the patient developed progressive headache, weakness and a documented deterioration in vision, which was accompanied by worsening of radiographic findings. A diagnosis of pseudoprogression was made and after limited benefit from a trial of dexamethasone, four cycles of bevacizumab were administered which resulted in rapid clinical and radiographic improvement. CONCLUSIONS: Our findings support the potential use of bevacizumab as a rescue agent for symptomatic pseudoprogression.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation.

PURPOSE: To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review. METHODS: An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed. RESULTS: Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results. CONCLUSION: Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

CPEO - Like mitochondrial myopathy associated with m.8340G>A mutation.

Two patients with an m.8340G>A mitochondrial DNA variant have been reported with one patient showing ptosis, ophthalmoparesis and myopathy at 53% heteroplasmy and another with pigmentary retinopathy, cataracts and sensory neural deafness and slightly higher heteroplasmy (65%). Here we report that higher muscle mutant heteroplasmy (93%) for m.8340G>A is associated with ptosis, ophthalmoparesis and mitochondrial myopathy, thus confirming the initial phenotypic association and showing that heteroplasmy per se does not explain the phenotypic spectrum of disease associated with the m.8340G>A mutation.

Recurrent Alternate-Sided Homonymous Hemianopia Due to Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-Like Episodes (MELAS): A Case Report.

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) can rarely cause alternate-sided homonymous hemianopia due to stroke-like episodes involving the occipital lobes, as reported in three previously published cases. The authors report an interesting case of a 16-year-old presenting with myoclonic epilepsy due to MELAS with the rare ND3 mitochondrial mutation T10191C, with recurrent alternate-sided homonymous hemianopia. Visual field and corresponding magnetic resonance imaging (MRI) findings are presented. To the authors' knowledge, this is the first report of recurrent alternate-sided homonymous hemianopia in MELAS with documented visual field and MRI findings with resolution between each episode.

Bilateral Compressive Optic Neuropathy from Renal Osteodystrophy Caused by Branchio-oto-renal Syndrome Stabilised After Parathyroidectomy.

Renal osteodystrophy can cause calvarial hypertrophy and narrowing of the neural canals and foramina. Compressive optic neuropathy is extremely rare in renal osteodystrophy and was reported once only. The authors report bilateral, simultaneous compressive optic neuropathy secondary to renal osteodystrophy with features of uremic leontiasis ossea in chronic renal failure caused by branchio-oto-renal syndrome. Because of the extensive calvarial hypertrophy and the surgical difficulties envisaged with optic canal decompression, conservative approach was pursued. The patient's visual acuity and fields improved after partial parathyroidectomy. Visual improvement may be explained by the arrest of renal osteodystrophy and reduced optic nerve compression after parathyroidectomy.

Optic chiasm involvement on MRI with ethambutol-induced bitemporal hemianopia.

While ethambutol optic neuropathy usually causes central or cecocentral scotomas, bitemporal visual field defects also have been reported. The pathogenesis of the bitemporal hemianopia has not been established. This article describes magnetic resonance imaging abnormalities involving the optic chiasm in a patient with bitemporal visual field loss. To our knowledge, these neuroimaging findings have not been previously described in association with ethambutol therapy.

Posterior reversible encephalopathy syndrome presenting as Balint syndrome.

Balint syndrome is a disorder of inaccurate visually guided saccades, optic ataxia, and simultanagnosia that typically results from bilateral parieto-occipital lesions. Visual perception disturbances in the posterior reversible encephalopathy syndrome (PRES) include hemianopia, visual neglect, and cerebral blindness, but Balint syndrome had not been recognized. We report Balint syndrome associated with PRES in a 37-year-old woman with acute hypertension and systemic lupus erythematosus. Balint syndrome can be an initial presentation of PRES.