Browsing by Author "Cherian, Ajith"
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Item A fisherman who could not row(LANCET, 2009)Item An elusive diagnosis: Scedosporium apiospermum infection after near-drowning(ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2010)A 51-year-old male was admitted in our institute following an episode of near-drowning. He later developed ventriculitis and cerebral ring-enhancing lesions. He died following a subarachnoid hemorrhage due to rupture of a mycotic aneurysm involving the right fetal posterior cerebral artery. Scedosporium apiospermum was isolated from the cerebrospinal fluid. Central nervous system invasion by S apiospermum may present insidiously in near-drowning patients and, therefore, requires a high index of suspicion. In cases with the characteristic cerebral ring-enhancing lesions and concomitant ventriculitis, treatment should be instituted while awaiting fungal culture. With this article we intend to alert neurologists, intensivists, and physicians to this near fatal infection, as early identification and prompt treatment with voriconazole may be life saving.Item Atonic variant of benign childhood epilepsy with centrotemporal spikes (atonic-BECTS): A distinct electro-clinical syndrome(BRAIN & DEVELOPMENT, 2012)Purpose: To describe the clinical and electroencephalographic features, treatment strategies and outcome in a series of children with the atonic variant of benign childhood epilepsy with centrotemporal spikes (atonic-BECTS).Material and methods: Out of the 148 patients with BECTS reviewed from January 2005 to June 2010 in our Institute, there were seven (5%) with atonic-BECTS. All underwent video EEG, high-resolution magnetic resonance imaging (MRI), neuropsychological evaluation and language assessment. Their progress was followed. In addition to sodium valproate, three were treated with steroids, followed by intravenous immunoglobulin (IVIG) when the seizures relapsed while tapering or after stopping the steroids.Results: All of the children had earlier onset (mean = 2.4 years), increased frequency and increased duration of focal seizures compared to typical BECTS. Head drop and truncal sway due to axial or axiorhizomelic atonia occurring several times per day or week was the key manifestation. The atonic seizures worsened with carbamazepine in three, clonazepam in two and clobazam in one. When the atypical seizures commenced, some children developed one or more of the following problems: hyperactivity, attention deficit, clumsy gait, and mild cognitive or language dysfunction. Three children became seizure free, one on steroids and the other two on IVIG.Conclusions: BECTS in children with an early age of onset and frequent and prolonged seizures is more likely to evolve into atonic-BECTS. Carbamazepine and some benzodiazepines may worsen these seizures. Three children became seizure free with immunomodulatory therapy, one on steroids and the other two on IVIG, and had complete resolution of the transient motor and cognitive impairment. Atonic-BECTS needs to be differentiated from Lennox-Gastaut syndrome since it is potentially treatable and children recover with no sequel. Although all the children in this series continued to be on treatment with sodium valproate it is currently undetermined whether they would have required to do so if followed up for an extended period of time. (c) 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.Item Concepts and Controversies in Nonketotic Hyperglycemia-Induced Hemichorea: Further Evidence from Susceptibility-Weighted MR Imaging(JOURNAL OF MAGNETIC RESONANCE IMAGING, 2009)Hyperglycemia-induced hemichorea can show T1 hyperintensity of the contralateral striatum on MRI. This is thought to be due to petechial hemorrhages or gemistocytic astrocyte accumulation. This study explores the utility of susceptibility-weighted imaging (SWI) and diffusion-weighted imaging (DWI) in identifying the nature of these lesions. Three patients underwent MR imaging of the brain with SE T1, F SE T2. DWI, and SWI. T1 images showed hyperintensity predominantly involving the contralateral striatum, where mild (two cases) to moderate (one case) restricted diffusion (low apparent diffusion coefficient [ADC]) was detected on DWI. SWI demonstrated bilateral symmetrical hypointensities in the first two cases, suggesting age associated mineralization. In addition, increased susceptibility change (hypointensity) was also noted in the right putamen in the first and the third cases, suggesting paramagnetic mineral deposition. T1 hyperintensity may be from the protein hydration layer inside the cytoplasm of swollen gemistocytes appearing after an acute cerebral injury. These astrocytes also express metallothionein with zinc, which is thought to be the cause of asymmetric hypointensity of the posterior putamen on SWI. ADC values were thought to be useful for prognostication: however, they should be interpreted cautiously in the presence of susceptibility changes.Item Do sphenoidal electrodes aid in surgical decision making in drug resistant temporal lobe epilepsy?(CLINICAL NEUROPHYSIOLOGY, 2012)Objective: The utility of sphenoidal electrodes (SPh) in analyzing interictal epileptiform discharges (IEDs) and ictal electrography remains controversial, despite its widespread use.Methods: One hundred and twenty-two consecutive patients with presumed temporal lobe epilepsy (TLE) who underwent presurgical evaluation were prospectively studied. SPh and Silverman's electrodes were placed, in addition to routine electrodes in 10-20 international system. IEDs and ictal electroencephalography (EEG) were analyzed separately in bipolar and referential montages. The proportion of patients selected for surgery after adjusting for SPh placement based on the earlier ictal onset and IEDs were analyzed.Results: Of the 8701 IEDs in SPh, only 65% were seen over the scalp bipolar montage; 1392 (16%) IEDs were confined to SPh electrodes, and were not seen at scalp bipolar montage (p < 0.001). Spike amplitudes were highest at SPh (p < 0.001). Of the 592 seizures analyzed, 62 (61%) had simultaneous SPh and scalp onset, while in 26 (25%) SPh onset preceded the scalp.Conclusions: Out of the 35 patients with unilateral mesial temporal sclerosis (MTS) with additional neocortical changes and/or non-lateralized bitemporal IEDs and/or diffuse ictal onset (group 1), 27 were selected for surgery (77%). About 7% was selected for surgery in this group by SPh placement. Also, in patients with bilateral MTS (group 2), 25% (5/20) were chosen for anterior temporal lobectomy, SPh provided an additional benefit in 11% (p < 0.001). Patients with normal magnetic resonance imaging (group 3) and temporal plus epilepsy (group 4) had a lower surgical yield, only 12% and 9.5% could undergo surgery. They were denied surgical candidacy with SPh (p < 0.001). Significance: One-third of patients after SPh placement were selected for resective surgery obviating the need for invasive monitoring. The maximum yield was noted in unilateral MTS (associated with additional neocortical features or non-lateralized bilateral temporal interictal IEDs or diffuse ictal onset in scalp EEG) and in bilateral MTS. Those with normal MRI/temporal plus epilepsy could be excluded from direct resective surgery. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.Item Ischemic hyperintensities on T1-weighted magnetic resonance imaging of patients with stroke: New insights from susceptibility weighted imaging(NEUROLOGY INDIA, 2010)Hyperintensities on T1-weighted magnetic resonance imaging (MRI) in the setting of brain ischemia are usually considered hemorrhagic transformations. Such changes can also be seen due to "incomplete infarction" with selective neuronal loss. Arguments regarding the cause of these T1 hyperintensities have shuttled between gemistocytic astrocyte accumulation, tissue calcification and paramagnetic substance deposition. Susceptibility weighted imaging (SWI), a sensitive modality for detecting paramagnetic agents and blood products, has never been used to resolve this issue. The study was aimed to evaluate the SWI signal changes of T1 hyperintense lesion in stroke patients and understand its usefulness in differentiating a hemorrhagic infarct and an incomplete infarct. All the seven patients with infarct, having hyperintensities on T1 weighted MRI seen over the last one year were subjected to SWI. In none of the patients SWI failed to show any blooming. By doing SWI for T1-weighted hyperintensities, we can differentiate hemorrhagic infarct and a non-hemorrhagic "incomplete infarct". This differentiation will immensely help in planning management strategy and prognostication.Item Muscle channelopathies and electrophysiological approach(ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2008)Myotonic syndromes and periodic paralyses are rare disorders of skeletal muscle characterized mainly by muscle stiffness or episodic attacks of weakness. Familial forms are caused by mutation in genes coding for skeletal muscle voltage ionic channels. Familial periodic paralysis and nondystrophic myotonias are disorders of skeletal muscle excitability caused by mutations in genes coding for voltage-gated ion channels. These diseases are characterized by episodic failure of motor activity due to muscle weakness (paralysis) or stiffness (myotonia). Clinical studies have identified two forms of periodic paralyses: hypokalemic periodic paralysis (hypoKPP) and hyperkalemic periodic paralysis (hyperKPP), based on changes in serum potassium levels during the attacks, and three distinct forms of myotonias: paramyotonia congenita (PC), potassium-aggravated myotonia (PAM), and myotonia congenita (MC). PC and PAM have been linked to missense mutations in the SCN4A gene, which encodes subunit of the voltage-gated sodium channel, whereas MC is caused by mutations in the chloride channel gene (CLCN1). Exercise is known to trigger, aggravate, or relieve symptoms. Therefore, exercise can be used as a functional test in electromyography to improve the diagnosis of these muscle disorders. Abnormal changes in the compound muscle action potential can be disclosed using different exercise tests. Five electromyographic (EMG) patterns (I-V) that may be used in clinical practice as guides for molecular diagnosis are discussed.Item Ode to epileptologists!(Annals of Indian Academy of Neurology, 2011)Item Periodic Lateralized Epileptiform Discharges in Fulminant Form of SSPE(CANADIAN JOURNAL OF NEUROLOGICAL SCIENCES, 2009)Item Post-irradiation "acquired cavernous angiomas" with drug resistant seizures(EPILEPSY RESEARCH, 2011)Cavernomas are well-known congenital vascular lesions with presumably high epileptogenicity. We report two patients who developed cavernomas; both were in remission from childhood acute lymphoblastic leukemia following standard chemo-radiotherapy. They developed drug-resistant focal epilepsy secondary to cavernomas and were subjected to surgical/medical management. This report highlights the ictogenesis of radiation-induced "acquired" cavernous angiomatosis in the brain. Appropriate treatment, including resection of these lesions in selected cases, improves the quality of life in such patients. (C) 2011 Elsevier B.V. All rights reserved.Item Teaching Video NeuroImages: Hypothalamic hamartoma An overlooked entity(NEUROLOGY, 2011)Item The nursing instructor's speech(LANCET, 2011)