Molecular Basis of Cerebral Vasospasm: What Can We Learn from Transcriptome and Temporal Gene Expression Profiling in Intracranial Aneurysm?

Cerebral vasospasm (CV) is a significant complication following aneurysmal subarachnoid hemorrhage (aSAH), and lacks a comprehensive molecular understanding. Given the temporal trajectory of intracranial aneurysm (IA) formation, its rupture, and development of CV, altered gene expression might be a molecular substrate that runs through these clinical events, influencing both disease inception and progression. Utilizing RNA-Seq, we analyzed tissue samples from ruptured IAs with and without vasospasm to identify the dysregulated genes. In addition, temporal gene expression analysis was conducted. We identified seven dysregulated genes in patients with ruptured IA with vasospasm when compared with those without vasospasm. We found 192 common genes when the samples of each clinical subset of patients with IA, that is, unruptured aneurysm, ruptured aneurysm without vasospasm, and ruptured aneurysm with vasospasm, were compared with control samples. Among these common genes, TNFSF13B, PLAUR, OSM, and LAMB3 displayed temporal expression (progressive increase) with the pathological progression of disease that is formation of aneurysm, its rupture, and consequently the development of vasospasm. We validated the temporal gene expression pattern of OSM at both the transcript and protein levels and OSM emerges as a crucial gene implicated in the pathological progression of disease. In addition, RSAD2 and ATP1A2 appear to be pivotal genes for CV development. To the best of our knowledge, this is the first study to compare the transcriptome of aneurysmal tissue samples of aSAH patients with and without CV. The findings collectively provide new insights on the molecular basis of IA and CV and new leads for translational research.

Establishing continuum in Transcranial Doppler characteristics of IIH, migraine and healthy controls- An exploratory study.

BACKGROUND: IIH is a severe form of headache that often has superimposed migraine and often it is very difficult to distinguish the two forms of headache. Intracranial hemodynamics is a relatively unexplored means of distinguishing between the two forms of headache. OBJECTIVES: We aimed to study intracranial flow dynamics using Transcranial Doppler in patients with IIH, migraine, and normal controls. MATERIALS AND METHODS: It was a hospital-based observational study that included 51 people with IIH, 87 people with migraine, and 101 healthy controls and all were subjected to TCD study after detailed clinical examination. RESULTS: Mean age of patients in three groups were similar with the mean age in IIH being 33.41 ± 10.75 (age in years ± SD). Vision loss was present in 66.67% of patients with IIH, and most common field defect was generalized constriction (27.5%). Neuroimaging was abnormal in 94.11% of patients of IIH with mean CSF pressure was 31.27±5.32 cm of water. Of all the TCD-measured velocities, mean flow velocity (MFV) showed a significant difference in all three groups with (p-value <0.001). The pulsatility index, both for middle cerebral arteries as well as ophthalmic arteries showed a significant difference in the three groups with the highest values in IIH patients (p-value<.001). The mean VMR in IIH (1.11±0.32) was lower than the mean VMR in migraine (1.34±0.43) as well as controls (1.49±0.46). CONCLUSION: TCD parameters like MFV and PI are useful parameters that show considerable variation and can be used to differentiate between IIH and migraine.

The Neuro-Ophthalmology of Tuberculosis.

Tuberculosis (TB) is a global health concern and central nervous system (CNS) TB leads to high mortality and morbidity. CNS TB can manifest as tubercular meningitis, tuberculoma, myelitis, and arachnoiditis. Neuro-ophthalmological involvement by TB can lead to permanent blindness, ocular nerve palsies and gaze restriction. Visual impairment is a dreaded complication of tubercular meningitis (TBM), which can result from visual pathway involvement at different levels with varying pathogenesis. Efferent pathway involvement includes cranial nerve palsies and disorders of gaze. The purpose of this review is to outline the various neuro-ophthalmological manifestations of TB along with a description of their unique pathogenesis and management. Optochiasmatic arachnoiditis and tuberculomas are the most common causes of vision loss followed by chronic papilloedema. Abducens nerve palsy is the most commonly seen ocular nerve palsy in TBM. Gaze palsies with deficits in saccades and pursuits can occur due to brainstem tuberculomas. Corticosteroids are the cornerstone in the management of paradoxical reactions, but other immunomodulators such as thalidomide and infliximab are being explored. Toxic optic neuropathy caused by ethambutol necessitates careful monitoring and immediate drug discontinuation. Cerebrospinal fluid diversion through ventriculo-peritoneal shunting may be required in patients with hydrocephalus in stage I and II of TBM to prevent visual impairment. Early diagnosis and prompt management are crucial to prevent permanent disability. Prevention strategies, public health initiatives, regular follow-up and timely intervention are essential in reducing the burden of CNS TB and its neuro-ophthalmological complications.

Pituitary Dysfunction in Idiopathic Intracranial Hypertension: An Analysis of 80 Patients.

BACKGROUND: Empty sella is a commonly described imaging entity in patients with idiopathic intracranial hypertension (IIH). Though menstrual and hormonal disturbances have been associated with IIH, available literature lacks systematic analysis of pituitary hormonal disturbances in IIH. More so, the contribution of empty sella in causing pituitary hormonal abnormalities in patients of IIH has not been described. We carried out this study to systematically assess the pituitary hormonal abnormalities in patients with IIH and its relation to empty sella. METHODS: Eighty treatment naïve patients of IIH were recruited as per a predefined criterion. Magnetic resonance imaging (MRI) brain with detailed sella imaging and pituitary hormonal profile were done in all patients. RESULTS: Partial empty sella was seen in 55 patients (68.8%). Hormonal abnormalities were detected in 30 patients (37.5%), reduced cortisol levels in 20%, raised prolactin levels in 13.8%, low thyroid-stimulating hormone (TSH) levels in 3.8%, hypogonadism in 1.25%, and elevated levels of gonadotropins were found in 6.25% of participants. Hormonal disturbances were independent and were not associated with the presence of empty sella (p = 0.493). CONCLUSION: Hormonal abnormalities were observed in 37.5% patients with IIH. These abnormalities did not correlate with the presence or absence of empty sella. Pituitary dysfunction appears to be subclinical in IIH and responds to intracranial pressure reduction, not requiring specific hormonal therapies.

Dysregulated Genes and Signaling Pathways in the Formation and Rupture of Intracranial Aneurysm.

Intracranial aneurysm (IA) has the potential to rupture. Despite scientific advances, we are still not in a position to screen patients for IA and identify those at risk of rupture. It is critical to comprehend the molecular basis of disease to facilitate the development of novel diagnostic strategies. We used transcriptomics to identify the dysregulated genes and understand their role in the disease biology. In particular, RNA-Seq was performed in tissue samples of controls, unruptured IA, and ruptured IA. Dysregulated genes (DGs) were identified and analyzed to understand the functional aspects of molecules. Subsequently, candidate genes were validated at both transcript and protein level. There were 314 DGs in patients with unruptured IA when compared to control samples. Out of these, SPARC and OSM were validated as candidate molecules in unruptured IA. PI3K-AKT signaling pathway was found to be an important pathway for the formation of IA. Similarly, 301 DGs were identified in the samples of ruptured IA when compared with unruptured IAs. CTSL was found to be a key candidate molecule which along with Hippo signaling pathway may be involved in the rupture of IA. We conclude that activation of PI3K-AKT signaling pathway by OSM along with up-regulation of SPARC is important for the formation of IA. Further, regulation of Hippo pathway through PI3K-AKT signaling results in the down-regulation of YAP1 gene. This along with up-regulation of CTSL leads to further weakening of aneurysm wall and its subsequent rupture.

Tonic down-rolling and eccentric down-positioning of eyes under sevoflurane anesthesia without non-depolarizing muscle relaxant and its relationship with depth of anesthesia.

Purpose: To analyze the relationship between eccentric downward eye movement/eccentric downward eye-positioning (EDEM/EDEP) encountered in patients undergoing ophthalmic surgeries and its return to a centralized position under general anesthesia (GA) with the depth of anesthesia (DOA). Methods: Patients undergoing ophthalmic surgeries (6 months-12 years) under sevoflurane anesthesia without non-depolarizing muscle relaxant (NDMR) who witnessed a sudden tonic EDEM/EDEP were both retrospectively (R-group) and prospectively (P-group) enrolled (ambispective study). R-group included data-points after induction (AI) till the time surgery lasted while P-group compiled data both during induction (DI) and AI. DOA in terms of MAC (minimum alveolar concentration) at the time of EDEM/EDEP and centralization of eyeball and their timings were noted and compared for both AI and DI data-points. Also, vertical eccentric eye positions were scored and correlated with MAC. Results: AI data included 22 (14R+8P) events and their mean MAC of EDEM/EDEP and centralization were 1.60 ± 0.25 and 1.18 ± 0.17 respectively (p = 0.000). DI data included 62 (P) cases and its mean MAC of EDEM/EDEP and centralization was 2.19 ± 0.43 and 1.39 ± 0.26 respectively (p = 0.000). Median (IQR) eye positions during down-positioning in 84 events was -3 (-3.9 to -2.5). It was preceded by an eccentric upward drift of eyes in 10/22 (6R+4P) AI cases. A strong negative correlation was seen between DOA and eccentric eye positions (r = -0.77, p = 0.000). Conclusions: Tonic down-rolling of eyes is not uncommon in children seen without NDMR with higher depths of sevoflurane anesthesia compared to point of centralization and fluctuations in DOA should be avoided to circumvent inadvertent complications during ocular surgery.

VENOUS OVERLOAD CHOROIDOPATHY ASSOCIATED WITH IDIOPATHIC INTRACRANIAL HYPERTENSION.

PURPOSE: To report a case of venous overload choroidopathy associated with idiopathic intracranial hypertension in a 41-year-old man. METHODS: History and clinical examination, fluorescein angiography, ultra-widefield indocyanine green angiography, swept-source optical coherence tomography, and contrast-enhanced magnetic resonance imaging. RESULTS: The patient was diagnosed as having idiopathic intracranial hypertension 2 years ago, was being managed on oral acetazolamide, and retained 20/20 visual acuity in both eyes until now when he presented with a complaint of visual loss in the right eye. Ophthalmoscopy revealed serous detachment in the fovea of the right eye. Swept-source optical coherence tomography showed the presence of subretinal fluid and detachments of the retinal pigment epithelium in both eyes. Fundus fluorescein angiography showed multiple dot leaks at the level of the retinal pigment epithelium in both eyes. Indocyanine green angiography revealed vortex vein anastomoses and choroidal vascular hyperpermeability in both eyes. Contrast-enhanced magnetic resonance imaging revealed dilated optic nerve sheath diameter and a partial empty sella and magnetic resonance venography showed bilateral stenosis of the transverse sinus. CONCLUSION: Transverse sinus stenosis is a common finding in "idiopathic" intracranial hypertension and contributes to the intracranial pressure through intracranial venous hypertension. Increased venous back pressure seemed to have overloaded the choroid resulting in choroidal vascular congestion and hyperpermeability, leaks from the level of the retinal pigment epithelium, and accumulation of subretinal fluid.

Role of vitreous cytology in the diagnosis of primary central nervous system lymphoma: A report of an unusual presentation.

Primary central nervous system lymphoma (PCNSL) is a rare subtype of non-Hodgkin lymphoma confined to the brain, spinal cord, meninges, intraocular compartment, and cranial nerves. Intraocular lymphoma (IOL) is a rare subtype of PCNSL. Intravitreal involvement by a PCNSL is an infrequent but potentially fatal event. The role of vitreous cytology in diagnosing IOLs is vital but has been sporadically described in the literature due to its variable sensitivity. Herein, we present a case of PCNSL, who primarily presented with ocular symptoms and could be accurately diagnosed based on vitreous cytology and subsequently confirmed on stereotactic brain biopsy.

Serum Calcitonin Gene-Related Peptide Is Elevated in Patients With Migraine and Ophthalmoplegia.

BACKGROUND: There is ongoing debate about whether the oculomotor (III), trochlear (IV), or abducens (VI) nerve paresis in patients with migraine is directly attributable to migraine (ophthalmoplegic migraine [OM]) or is due to an inflammatory neuropathy (recurrent painful ophthalmoplegic neuropathy [RPON]). As migraine is associated with elevated serum calcitonin gene-related peptide (CGRP) levels, we studied serum CGRP levels among patients with OM/RPON to determine whether they are elevated during and between attacks. This is the first study assessing CGRP levels in the serum of patients with OM/RPON. METHODS: The aim of this case-control study was to assess serum CGRP levels in patients with ophthalmoplegia and a headache consistent with migraine according to ICHD-3 criteria. Serum CGRP levels were measured during the ictal and interictal phases in 15 patients with OM/RPON and compared with age-matched and sex-matched controls without migraine (12 patients). RESULTS: The median serum CGRP levels were significantly elevated ( P = 0.021) during the ictal phase (37.2 [36.4, 43.6] ng/L) compared with controls (32.5 [30.1, 37.3] ng/L). Serum CGRP levels during the attack correlated with the total duration of ophthalmoplegia. A CGRP level of 35.5 ng/L in the ictal phase of the attack had a sensitivity of 86.7% and specificity of 75.0% in diagnosing a patient with OM/RPON. CONCLUSIONS: Elevated serum CGRP levels during the ictal phase of OM/RPON favor migraine as the underlying cause of episodic headache with ophthalmoplegia.

The Genetics of Ethambutol-Induced Optic Neuropathy: A Narrative Review.

Tuberculosis (TB) is a global health problem with the major brunt of disease occurring in developing countries. The cornerstone of treatment of TB is anti-tubercular therapy (ATT), which includes rifampicin, isoniazid, pyrazinamide and ethambutol. Because of emerging drug resistance, treatment failures, defaulters and increasing incidence of disseminated and extrapulmonary TB, the guidelines have been modified in some countries. Ethambutol is prescribed for longer times (in some cases >8 months) and hence the incidence of ethambutol-induced optic neuropathy (EtON) is expected to rise. The fundamental question which needs explanation is why only a small subset of patients on ethambutol are prone to develop loss of vision. This review focuses on available genetic studies which provide evidence that mitochondria are the likely substrates involved in the final pathway of reactive oxidative damage of the papillo-macular bundle. Genetic analysis of mitochondrial mutations encoding genes involved in oxidative phosphorylation pathways may help in isolating the subset of patients who are genetically susceptible. If the groups having high risk of developing EtON are recognised then prolonged duration of ethambutol treatment can be avoided in these susceptible individuals. A better understanding of the pathophysiology will also pave the way for the development of management strategies in this condition.

Therapeutic Plasma Exchange in Neuromyelitis Optica Spectrum Disorders-Experience from Tertiary Care Center in North India.

Background: Therapeutic plasma exchange (TPE) is indicated in the acute presentation of neuromyelitis optica spectrum disorders (NMOSD) as category II indication as per American Society for Apheresis guidelines 2016. Aim: To assess the efficacy of TPE in symptomatic patients of NMOSD not responding to high dose intravenous steroids. Patients and Methods: We retrospectively reviewed the record of TPE procedures in NMOSD patients over a period of 3 years (2013-2016). TPEs were done on Cobe® spectra (Terumo BCT, Lakewood Co., USA) using 5% human serum albumin or fresh frozen plasma as replacement fluid. Clinical improvement was recorded post-procedure and adverse reactions if any was noted. Results: We performed TPE in 11 clinically diagnosed patients of NMOSD. Three (27%) patients had only visual symptoms, five (46%) had both visual as well as muscular symptoms, whereas three (27%) patients presented with only muscular symptoms. Out of seven tested, three patients were aquaporin-4-immunoglobulin-G-positive (AQP4-IgG positive). Visual symptoms improved from no vision pre-TPE therapy to finger counting or 6/24 post-therapy.The muscle power of the limbs improved by grade one to grade two post-therapy. Adverse events were observed in 8% (5/62) of the procedures; allergic reactions to replacement fluid as the most common event (n = 3) followed by hypotension (n = 2). Follow-up was available in 81% (9/11) patients. Two patients died at 3 and 12 months of follow-up. One patient had relapsed and underwent a second TPE cycle. Conclusion: The addition of TPE as a part of therapy is effective and safe in acute exacerbations of NMOSD.

Successful Use of High Dose Methotrexate in Treatment of Primary CNS Lymphoma Patients Without Access to Serum Methotrexate Levels Monitoring: Challenges and Outcome.

AIMS AND OBJECTIVES: High dose methotrexate (HDMTx) based chemotherapy forms the backbone of therapy for patients with Primary Central Nervous system Lymphoma (PCNSL). However, delivering HDMTx in resource constrained settings, especially without therapeutic drug monitoring, is difficult. We share our experience of treatment of patients with PCNSL at our center over a 10-year period with local adaptations made to deliver HDMTx. MATERIALS AND METHODS: We retrospectively analysed the case records of patients diagnosed with a PCNSL over the course of 10 years from 2010 to 2020. RESULTS: Fifty-five patients received therapy for newly diagnosed PCNSL. Thirty-six patients received Modified De-Angelis protocol ± Rituximab with curative intent. Fourteen of these patients were unable to complete the protocol with the most common cause being development of methotrexate toxicity. Patients unable to complete the designated 5 cycles of HDMTx had a poorer PS and higher probability of having a high IELSG score at baseline. Nineteen patients were given non HDMTx based therapy either due to advanced age or poor performance status. Twenty-nine patients (52.7%) were able to achieve a complete response. The most common cause of mortality was relapse/progressive disease. The Median EFS and OS of the cohort was 29 months and 40 months respectively. CONCLUSION: All attempts should be made to have therapeutic drug level monitoring for administration of HDMTX based therapy for the patients with PCNSL, more so in patients who have poor performance status and a high IELSG score. If it is imperative to give HDMTx without access to TDM facility then a possible risk of higher toxicity should be explained to all patients, beforehand.