R.D. Bharath

Neurosyphilis: MRI features and their phenotypic correlation in a cohort of 35 patients from a tertiary care university hospital

IntroductionThe clinical and MR imaging features of neurosyphilis are highly varied. In this study, we describe the spectrum of the imaging findings in patients with neurosyphilis.MethodsThe MR imaging observations of 35 patients diagnosed to have neurosyphilis on the basis of cerebrospinal fluid reactive for the Venereal Disease Research Laboratory test were reviewed.ResultsAll the 35 patients, including four with human immunodeficiency virus coinfection, met the CDC diagnostic criteria for neurosyphilis. Patients were classified into three groups: (1) neuropsychiatric, (2) meningovascular, and (3) myelopathic, based on the dominant clinical manifestations. Fourteen patients with neuropsychiatric manifestations showed diffuse cerebral atrophy (14), parenchymal signal changes in the mesial temporal region (2) and temporal and basifrontal regions (1), infarcts (3), and nonspecific white matter changes (3). Eleven patients with meningovascular form showed infarcts (6), diffuse cerebral atrophy (3), signal changes in the mesial temporal region (3), sulcal exudates (1), progressive multifocal leukoencephalopathy (1), and a mass surrounding the carotid sheath (1). Spine imaging in ten patients with myelopathy showed long-segment signal changes (5), contrast enhancement (2), and dorsal column involvement (2). Three of these patients had normal spinal study. Six patients in the myelopathic group also underwent brain MRI that showed signal changes in the temporal region (2) and frontal region (1), multiple infarcts (1), and enhancing hypothalami (1). Three patients had normal study.ConclusionMRI abnormalities in neurosyphilis are protean and mimic of many other neurological disorders and thus require a high index of suspicion to reduce diagnostic omissions.

Tumefactive demyelination: clinical, imaging and follow-up observations in thirty-nine patients

We describe the clinical, neuroimaging and pathological features and therapeutic outcome in a large cohort of 39 patients with tumefactive demyelination.

Clinico-pathological factors influencing surgical outcome in drug resistant epilepsy secondary to mesial temporal sclerosis

BACKGROUND Mesial temporal sclerosis (MTS) is the most common cause of drug resistant epilepsy amenable for surgical treatment and seizure control. METHODS This study analyzed the outcome of patients with MTS following anterior temporal lobectomy and amygdalohippocampectomy (ATL-AH) over 10 years and correlated the electrophysiological and radiological factors with the post operative seizure outcome. RESULTS Eighty seven patients were included in the study. Sixty seven (77.2%) patients had an Engel Class 1 outcome, 9 (11.4%) had Class 2 outcome. Engels class 1 outcome was achieved in 89.9% at 1 year, while it reduced slightly to 81.9% at 2 years and 76.2% at 5 year follow up. Seventy seven (88.5%) patients had evidence of hippocampal sclerosis on histopathology. Dual pathology was observed in 19 of 77 specimens with hippocampal sclerosis, but did not influence the outcome. Factors associated with an unfavorable outcome included male gender (p=0.04), and a higher frequency of pre-operative seizures (p=0.005), whereas the presence of febrile seizures (p=0.048) and loss of hippocampal neurons in CA4 region on histopathology (p=0.040) were associated with favorable outcome. The effect of CA4 loss on outcome is probably influenced by neuronal loss in other subfields as well since isolated CA4 loss was rare. Abnormal post operative EEG at the end of 1 week was found to be a significant factor predicting unfavorable outcome (p=0.005). On multivariate analysis, the pre-operative seizure frequency was the only significant factor affecting outcome. CONCLUSIONS The present study observed excellent seizure free outcome in a carefully selected cohort of patients with MTS with refractory epilepsy. The presence of dual pathology did not influence the outcome.

Evolution of MRI changes in Rasmussen's encephalitis.

We studied the MRI findings in 16 patients with Rasmussens encephalitis (RE), further analysed serial MRI changes in 11 of them and correlated it with clinical features.

Dexmedetomidine anesthesia enhances spike generation during intra-operative electrocorticography: A promising adjunct for epilepsy surgery.

BACKGROUND Anesthetic-induced suppression of cortical electrical activity is a major concern during epilepsy surgery. Dexmedetomidine (Dex) has been recently evaluated in a few small series for its effect on the electrocorticographic spikes intra-operatively. METHODS In this prospective study, electrocorticogram (ECoG) was monitored during dexmedetomidine infusion in 34 patients (M:F=23:11, age=29.2 ± 10.9 years; duration of epilepsy=15.3 ± 8.9 years) undergoing anterior temporal lobe resection with amygdalo-hippocampectomy for drug-resistant mesial temporal lobe epilepsy (Right: 18, Left: 16). Anesthesia was induced with thiopental/propofol and maintained with oxygen-N2O-isoflurane. ECoG was recorded for 5 min after the end tidal MAC of N2O and isoflurane were decreased to zero; anesthesia was maintained with O2:Air=50:50, vecuronium and fentanyl. ECoG was recorded using a 4-contact strip electrode for: (a) 5 min prior to dexmedetomidine (PreDEX), (b) 5 min during dexmedetomidine infusion (DEX; 1 μg/kg) and (c) 5 min after stopping dexmedetomidine (PostDEX). RESULTS The ECoG spikes were manually counted in all the channels. The mean spike rate in the 2 channels with maximum spikes (MAX CH A and MAX CH B) was normalized to a 3-min duration. RM-ANOVA and post hoc comparison of three phases were used to compare the spike rates. The mean spike rate during Dex phase was higher compared to preDEX (MAX CH B: p=0.007 and MAX CH A: p=0.079) and PostDEX (MAX CH B: p=0.17, MAX CH A: p=0.79) phases. The spike rate increased in 67.6% patients, while 11.8% patients showed ≤ 25% reduction and 20.6% patients showed >25% reduction in spike frequency. CONCLUSION Dexmedetomidine is useful during intra-operative ECoG recording in epilepsy surgery as it enhances or does not alter spike rate in most of the cases, without any major adverse effects.

Clinical, neuroimaging and pathological features of 5-nitroimidazole-induced encephalo-neuropathy in two patients: Insights into possible pathogenesis

We report two patients manifesting with involvement of central and peripheral nervous system with brain magnetic resonance imaging (MRI) changes and pathological features of neuropathy possibly due to harmful and chronic use of various nitroimidazole group of medications for recurrent diarrheal illness. Patient 1, a 21-year-old man with obsessive-compulsive disorder, impulsive behavior and harmful use of substance (tinidazole), had developed encephalopathy and biopsy-proven neuropathy with partial remission. The MRI of brain showed involvement of bilateral caudate, lentiform and dentate nuclei, and splenium, with contrast enhancement of the caudate and putaminal lesions and restricted diffusion of the splenial lesion. Patient 2 was a 50-year-old woman with irritable bowel syndrome and was on harmful use of tinidazole and metronidazole. She manifested with encephalopathy, ataxia, and neuropathy. Her MRI of brain revealed involvement of bilateral putamen, dentate nuclei and periventricular white matter with restricted diffusion. Sural nerve biopsy revealed evidence of vasculitic neuropathy. At follow-up, there was definite, though incomplete, recovery in both the patients. The MRI alterations improved completely in patient 2 and substantially in patient 1. Increasing awareness among the physicians may enable early recognition of potentially reversible neurotoxicity and avoid unwarranted prescription of such medications.

Monitoring peri-ictal changes in heart rate variability, oxygen saturation and blood pressure in epilepsy monitoring unit

PURPOSE The peri-ictal autonomic disturbances have been studied as predictors of seizure outcome and as markers of seizure onset. We studied the changes in heart rate (HR), HRV, oxygen saturation and blood pressure (BP) in the peri-ictal period in patients with drug-resistant localization-related epilepsy. METHODOLOGY Ninety one subjects undergoing video-EEG monitoring, underwent continuous HR, SpO2, BP and Lead II ECG monitoring. The changes during the preictal, ictal and postictal periods were analyzed for 57 seizures in 42 patients with artifact-free recordings and correlated with VEEG ictal onset and MRI characteristics. RESULTS Ictal tachycardia was noted in 15 (26.3%) seizures, of which, 60% had temporal lobe onset. HR increased by an average of 20.1% from pre-ictal to ictal phases (p=0.04). Ictal bradycardia was noted in one event with right temporal seizure onset. Heart rate variability (HRV) analysis of the preictal, ictal and postictal phases showed an increase in the sympathetic and decrease in parasympathetic activity during the ictus with relatively preserved total power. Ictal oxygen desaturation (84.1%±3.5%) was noticed in 10 (17.5%) seizures. Ictal hypertension was observed in 15 (26.3%); ictal hypotension was noted in 5 (8.7%) seizures. Both the systolic BP and diastolic BPs increased from the pre-ictal to ictal phase (p=0.01). CONCLUSIONS Peri-ictal dysautonomia can present in variable patterns and can be measured and compared over different modalities such as BP, HR and HRV. Though degree of tachycardia and increase in BP were higher during extratemporal onset of seizures, a fall in variability was noted in seizures of temporal lobe origin. Oxygen desaturation is not an uncommon event during the peri-ictal period in localization related epilepsy.

Clinical, electrophysiological, imaging, pathological and therapeutic observations among 18 patients with Rasmussen’s encephalitis

We studied the clinical, electrophysiological, imaging and pathological features of 18 patients with Rasmussens encephalitis (RE). This descriptive study included 18 patients (six males, 12 females) with RE who were evaluated for demographic and phenotypic details, electroencephalogram (EEG) results, MRI results, pathological features, virological markers and outcome. Radiological staging as per Bien et al. and pathological staging in accordance with Robitaille et al. were performed. Simple partial seizures were the most common initial manifestation. During the disease course, epilepsia partialis continua (EPC) developed in 15/18 (83.3%) and hemiparesis in 17/18 (94.4%) patients. EEG revealed hemispheric slowing (100%), interictal epileptiform discharges (100%) and ictal pattern (44.4%). Brain MRI revealed unihemispheric focal cortical atrophy (100%), white matter changes (88.2%), basal ganglia-ipsilateral caudate and putamen involvement (50.0%) and progression of atrophy on serial MRI (100%). Unusual presentations in this series included late onset (n=1), and isolated lingual EPC (n=1). Diagnostic biopsies in two patients revealed Robitaille stage 3 disease. The six hemispherotomy specimens showed stage 2 disease in one, stage 3 in three and stage 4 in two cases. Heterogeneity in disease stage in the different neuroanatomical regions and within the same cortical segment reflected progression of immune-mediated damage. Immunomodulation provided only temporary benefit. Patients who underwent functional hemispherotomy had reduction in seizure frequency and improved quality of life. The clinical, EEG and MRI findings are in accordance with the established literature. MRI staging was concordant with Robitaille pathological staging. Immunomodulation did result in transient reduction in seizure frequency while surgery in six produced reasonable benefit.

Reduced small world brain connectivity in probands with a family history of epilepsy

The role of inheritance in ascertaining susceptibility to epilepsy is well established, although the pathogenetic mechanisms are still not very clear. Interviewing for a positive family history is a popular epidemiological tool in the understanding of this susceptibility. Our aim was to visualize and localize network abnormalities that could be associated with a positive family history in a group of patients with hot water epilepsy (HWE) using resting‐state functional magnetic resonance imaging (rsfMRI).

Steroid-responsive encephalopathy in autoimmune thyroiditis: Clinical spectrum and MRI observations in three cases

Hashimotos encephalopathy (H.E.) is probably of autoimmune etiology, and manifests with seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms, myoclonus. It is presumed to be autoimmune in origin with high serum titers of antithyroid peroxidase antibodies (anti-TPA). Thyroid function might often be normal. The diagnosis is arrived at by excluding other toxic, metabolic and infectious causes of encephalopathies, supportive clinical profile, elevated thyroid antibodies and optimum steroid response. We present the characteristic phenotypic manifestations, magnetic resonance imaging and electroechography observations and response to immunomodulation with follow-up in three cases of H.E. All the three cases manifested with subacute to chronic progressive encephalopathy, cerebellar dysfunction, seizures, behavioral abnormalities and oculomotor disturbances and had evidence of hypothyroidism, elevated titers of anti-TPA and positive thyroid anti-microsomal antibodies. Atypical and uncommon presentations are known. This report emphasizes that a high index of suspicion is often required in cases with “investigation negative encephalopathy” for early diagnosis of H.E.