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Biomedical subjects

K Radhakrishnan

Publications and source records attributed to K Radhakrishnan.

At least 19 recordsLinked to original sources
PubMed2007

Risk factors for acute ischaemic stroke in young adults in South India.

BACKGROUND: Stroke is a leading cause of death and disability in developing countries, afflicting individuals at a young age. The contribution of established vascular risk factors to ischaemic stroke in young adults has not been evaluated systematically in Indians. METHODS: We conducted a case control study in 214 South Indian patients with first acute ischaemic stroke that occurred between the ages of 15 and 45 years, 99 age and sex matched hospital controls and 96 community controls. We compared the prevalence of the following risk factors: smoking, elevated blood pressure, high fasting blood glucose and abnormal lipids. RESULTS: Compared with community controls, stroke patients had a higher prevalence of smoking (multivariable adjusted odds ratio (OR) 7.77, 95% CI 1.93 to 31.27), higher systolic blood pressure (OR per SD increment of 1.88, 95% CI 1.01 to 3.49) and fasting blood glucose (OR per SD increment of 4.55, 95% CI 1.63 to 12.67), but lower high density lipoprotein (HDL) cholesterol (OR per SD increment of 0.17, 95% CI 0.09 to 0.30). Compared with hospital controls, stroke patients had a higher prevalence of smoking (OR 3.95, 95% CI 1.61 to 9.71) and lower HDL cholesterol (OR per SD increment 0.27, 95% CI 0.17 to 0.44). The presence of > or = 3 metabolic syndrome components was associated strongly with stroke (OR 4.76, 95% CI 1.93 to 11.76; OR 2.09, 95% CI 1.06 to 4.13) compared with community and hospital controls. CONCLUSIONS: Key components of the metabolic syndrome and smoking are associated with ischaemic stroke in young South Indian adults. Our observations underscore the importance of targeting adolescents and young adults for screening and prevention to reduce the burden of ischaemic stroke in young adults.

Adolescent↗
PubMed2006

Reversible periictal MRI abnormalities: clinical correlates and long-term outcome in 12 patients.

Although a wide spectrum of reversible periictal magnetic resonance imaging (MRI) abnormalities (RPMA) are being increasingly identified, the clinicians are often in a dilemma about their localization significance. This prompted us to analyze the clinical, MRI, electroencephalographic (EEG) and follow-up data of 12 patients with RPMA seen in a tertiary referral epilepsy center. RPMA occurred after a single or a cluster of focal seizures with or without secondary generalization. The interictal and ictal EEG abnormalities were localized to the site of RPMA in nine patients. RPMA involved areas remote from the site of EEG abnormalities in four patients. We have developed a comprehensive classification to account for the wide spectrum of RPMA involving gray matter, white matter and leptomeninges with or without contrast enhancement or mass effect. Follow-up MRIs showed complete resolution of RPMA in all, except in four patients, who developed residual focal atrophy. During median follow-up period of 3 years, recurrence of RPMA was observed in two patients. Diffusion weighted MRI in two patients and histopathological finding in one patient favored causal role of hypoxia in the pathogenesis of RPMA. Our observations help to understand the electroclinical profile, radiological spectrum, localization significance and natural history of RPMA better.

Adolescent↗
PubMed2006

Hemimegalencephalic appearance of normal hemisphere in unilateral heterotopia and absent corpus callosum.

We report two patients with medically refractory epilepsy who had MRI evidence of unilateral subcortical nodular heterotopia and agenesis of corpus callosum. The abnormal hemisphere was small, whereas the contralateral normal hemisphere appeared large and crossed the midline. Although the normal hemisphere was initially mistaken for hemimegalencephaly, there were no typical radiological features. Moreover, the electroencephalographic abnormalities lateralized to the hemisphere showing heterotopia. Because contralateral hemispheric abnormalities like heterotopia, hemimicrencephaly, and hemimegalencephaly can occur in patients with hemispheric heterotopias, we emphasize the importance of careful scrutiny of the contralateral hemisphere in patients with unilateral heterotopia. Absence of typical radiological features and appropriately lateralized electroencephalographic abnormalities will help differentiate the two. This is crucial when planning epilepsy surgery.

Adult↗
PubMed2004

Injuries due to seizures in persons with epilepsy: a population-based study.

BACKGROUND: Previous studies of injuries due to epileptic seizures predominantly involved patients with intractable epilepsy. These studies may have overestimated the risk of injuries in persons with epilepsy. METHODS: Patients consisted of 247 Rochester, MN, residents who were diagnosed with epilepsy between 1975 and 1984. Seizure-related injuries were defined as any injury, other than orolingual trauma, resulting from a seizure, sufficient for the patient to seek medical attention or for injury occurrence to be determined during the course of medical care. To identify risk factors for injury, characteristics of patients with seizure-related injury were compared with those without injury. RESULTS: During a total of 2,714 patient-years of follow-up, 62 seizure-related injuries were identified in 39 patients (16%, one injury in every 44 person-years). Most injuries involved cranial soft tissue contusions or lacerations (79%). The majority of seizure-related injuries (82%) occurred during generalized convulsive seizures. Univariate analyses identified five potential risk factors for seizure-related injury: greater number of antiepileptic drugs used, less independent living situation, higher Rankin score, history of generalized convulsive seizures or drop attacks, and higher seizure frequency score. Seizure frequency, however, was the only significant risk factor identified by multivariate analysis (p < 0.001; relative risk, 1.33). CONCLUSIONS: This population-based study shows that seizure-related injuries are infrequent and generally of minor severity. In most epilepsy patients, excessive restriction of daily activities to avoid injury is unnecessary. Effective seizure control reliably reduces the risk of seizure-related injuries.

Adolescent↗
PubMed2004

Antiulcer activity of Utleria salicifolia rhizome extract.

The effect of 50% ethanolic extract of Utleria salicifolia (USE) was assessed in different acute and chronic gastric ulcer models in rats. USE, 50-200 mg/kg administered orally, twice daily for 5 days showed dose-dependent ulcer protective effect in pylorus ligation (14.48-51.03% protection, P < 0.5 to P < 0.01), aspirin (28.80-56.52% protection, P < 0.5 to P < 0.001), ethanol (13.22-60.74% protection, P < 0.5 to P < 0.001), cold-restraint stress (21.22-77.14% protection, P < 0.05 to P < 0.001), and acetic acid (20.0-84.37% protection, P < 0.5 to P < 0.001)-induced acute and chronic ulcers. USE also significantly (P < 0.001) reduced the ulcer incidence (50 and 10%) and severity (67.83 and 91.34% protection) of duodenal ulcer, induced by cysteamine. Besides USE offered protection (53.52 and 60.58%) against ethanol-induced depletion of gastric wall mucus. However, USE reduced the ulcer index with significant decrease in plasma corticosterone (25.53 and 39.52% protection, P < 0.1 and P < 0.05), lipid peroxidation (18.75 and 47.92% protection, P < 0.01 and P < 0.001), superoxide dismutase (15.80 and 26.61% protection, P < 0.05 and P < 0.001) and increased in catalase (28.42 and 71.0% protection, P < 0.05 and P < 0.001) activity, respectively. Preliminary phytochemical screening of the USE gave the positive test for steroids, alkaloids, terpenoids, saponins and tannins. The HPTLC studies in the toluene: ethyl acetate: formic acid and the densitometric scanning at 254 nm gave three major spots with area corresponding to 28.16, 17.17, and 13.79% at 0.69, 0.78, and 0.88 R(f) values, respectively. The results indicate that USE possesses antiulcer activity.

Acetic Acid↗
PubMed2004

Seizure outcome after anterior temporal lobectomy and its predictors in patients with apparent temporal lobe epilepsy and normal MRI.

PURPOSE: Very little reliable information is available regarding the role of anterior temporal lobectomy (ATL), optimal presurgical evaluation strategy, post-ATL seizure outcome, and the factors that predict the outcome in patients with medically refractory temporal lobe epilepsy (TLE) and normal high-resolution magnetic resonance imaging (MRI). To be cost-effective, epilepsy surgery centers in developing countries will have to select candidates for epilepsy surgery by using the locally available technology and expertise. METHODS: We reviewed the electroclinical and pathological characteristics and seizure outcome of 17 patients who underwent ATL for medically refractory TLE after being selected for ATL based on a noninvasive selection protocol without the aid of positron emission tomography (PET) or single-photon emission computed tomography (SPECT), despite a normal preoperative high-resolution MRI. RESULTS: Seven (41%) patients achieved an excellent seizure outcome; five of them were totally seizure free. An additional five (29%) patients had >75% reduction in seizure frequency. The following pre-ATL factors predicted an excellent outcome: antecedent history of febrile seizures, strictly unilateral anterior temporal interictal epileptiform discharges (IEDs), and concordant type 1 ictal EEG pattern. All the five patients with pathologically verified hippocampal formation neuronal loss were seizure free. The presence of posterior temporal, bilateral temporal, and generalized IEDs portended unfavorable post-ATL seizure outcome. CONCLUSIONS: A subgroup of patients destined to have an excellent post-ATL outcome can be selected from MRI-negative TLE patients by using history and scalp-recorded interictal and ictal EEG data. The attributes of these patients are antecedent history of febrile seizures, strictly unilateral anterior IEDs, and concordant type 1 ictal EEG pattern.

Adolescent↗
PubMed2004

Blindness, ophthalmoplegia and extensive radiculopathy: an unusual clinical syndrome in intracranial sino-venous thrombosis.

Isolated intracranial hypertension is a common manifestation of intracranial sino-venous thrombosis (ISVT). Markedly elevated intracranial tension presents with unusual features including cranial neuropathies and radiculopathy. We report two cases with ISVT, which presented with headache, papilledema, progressive visual loss, complete ophthalmoplegia and flaccid areflexic quadriparesis along with a normal sensorium. Magnetic resonance imaging (MRI) of the brain and cervical spinal cord showed no lesions that could account for the neurological deficits. Markedly elevated lumbar CSF pressure was noted in both cases. Nerve conduction study favored radiculopathy in one case and was normal in the other. Raised intracranial pressure was found to be the sole cause for the clinical manifestations. Visual impairment persisted in one patient despite lumbo-peritoneal shunting while the other died of septicemia. To our knowledge there are no previous reports of a syndrome comprising blindness, ophthalmoplegia and flaccid quadriplegia due to intracranial hypertension in ISVT.

Adult↗
PubMed2004

Two cases of valproate-induced hyperammonemic encephalopathy without hepatic failure.

We report two children with localization related epilepsies, who presented with somnolence, seizure exacerbation, behavioral alteration, decline in speech and cognitive abilities, and ataxia while being treated with a combination of valproate and topiramate, but had previously tolerated valproate with other antiepileptic drugs. These children had elevated serum ammonia, normal transaminase levels, and generalized slowing of EEG background activity during encephalopathy, which promptly reverted back to normal along with clinical improvement following withdrawal of valproate. To our knowledge, this is the first documentation of valproate-induced hyperammonemic encephalopathy enhanced by topiramate from India. We intend to alert internists, pediatricians, psychiatrists and neurologists about this underrecognized adverse effect of antiepileptic drug polytherapy.

Ammonia↗
PubMed2003

Differential diagnosis of patients with intracranial sinus venous thrombosis related isolated intracranial hypertension from those with idiopathic intracranial hypertension.

In patients presenting with intracranial hypertension without hydrocephalus, mass lesions, and with normal cerebrospinal fluid (CSF) composition (pseudotumor cerebri syndrome), the diagnosis of intracranial sinus venous thrombosis (ISVT) has crucial etiological, therapeutic and prognostic implications. Utilizing two well-defined groups of pseudotumor cerebri patients, one with magnetic resonance imaging (MRI) or angiography confirmed ISVT (17 patients) and the other in whom ISVT has been excluded (idiopathic intracranial hypertension [IIH], 27 patients), we investigated the characteristics that might be helpful in distinguishing them. No clinical or auxiliary findings differed between the ISVT and IIH groups except for female gender and lower CSF protein level, which were significantly associated with the latter. While the syndrome pseudotumor cerebri could be due to multiple causes including ISVT, the term IIH should be restricted for patients with isolated intracranial hypertension attributable to no other neurological or systemic disease. Since CT frequently misses ISVT, patients with pseudotumor cerebri syndrome should undergo MRI and MR venography before being labeled as IIH. We conclude that Modified Dandy's Diagnostic Criteria of pseudotumor cerebri, formulated prior to MRI era, can no longer be applied for the diagnosis of IIH.

Adolescent↗
PubMed2003

Genetic association analysis of KCNQ3 and juvenile myoclonic epilepsy in a South Indian population.

Juvenile myoclonic epilepsy (JME) is a common subtype of idiopathic generalized epilepsy that shows a complex pattern of inheritance. We have tested the association between JME phenotype and an intragenic marker in KCNQ3 by using the transmission disequilibrium test in 119 probands and their parents. Mutations in KCNQ3 are known to cause benign familial neonatal convulsions and are involved in the physiologically important M current in neurons. Our results provide suggestive evidence of allelic association between JME and KCNQ3 ( P-value=0.008) and raise an interesting possibility of a genetic contribution to JME, viz., of a gene that causes a monogenic form of human epilepsy.

Brain↗
PubMed2003

Clinical characteristics of a South Indian cohort of juvenile myoclonic epilepsy probands.

Despite the distinctive clinical and electroencephalographic features known for five decades, even today, juvenile myoclonic epilepsy (JME) is frequently unrecognised and misdiagnosed in both developed and developing countries. Utilising 183 JME probands belonging to the South Indian state of Kerala, assembled through a tertiary referral centre for molecular genetic studies, we explored the phenotypic peculiarities, clinical genetics, and problems and pitfalls in the diagnosis of JME. At referral, only six (3.3%) patients carried the diagnostic label of JME, default in diagnosis resulted from failure to elicit the history of myoclonic jerks by the referring physicians. During the mean delay of 8.6 +/- 7.0 years in diagnosing JME, seizure control in the majority was poor due to inappropriate antiepileptic drug (AED) therapy. A history of epileptic seizures was obtained in 6.2% of the first-degree and 2.2% of the second-degree relatives of the probands; 37.7 and 11.1% of them, respectively, were diagnosed as JME. Although most of the clinical features of our cohort were in accordance with the literature, two notable differences we observed were the relatively increased occurrence of absence seizures and low frequency of photoparoxysmal responses. Although the variability in the clinical characteristics of JME may be apparent due to differences in the ascertainment of the data, they may well be an expression of a true clinical heterogeneity, and are in accordance with the complex and variable mode of inheritance and conflicting linkage studies reported for this syndrome from different ethnic groups.

Adolescent↗
PubMed2003

The significance of corpora amylacea in mesial temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) associated with mesial temporal sclerosis (MTS), mesial TLE (MTLE), is the commonest medically refractory adult epilepsy syndrome. Corpora amylacea (CoA) have been shown to be a marker of MTS. We compared 9 patients with MTS who had dense deposition of CoA in their hippocampi with 25 patients with MTS who did not have CoA. The patients with CoA were significantly older and they showed a trend towards having a significantly longer duration of epilepsy. The postoperative seizure outcome at 2 years was not different in the 2 groups. Our results could indicate the progressive nature of the pathology of MTS, probably indicating excitotoxic damage due to recurrent seizures, but they need to be verified by clinicopathological correlation among a larger number of patients with MTLE.

Adult↗
PubMed2002

Epilepsia partialis continua--a clinical and electroencephalography study.

Epilepsia partialis continua (EPC) is a rare type of localization-related motor epilepsy. Clinical spectrum, electroencephalography (EEG) characteristics and various prognostic factors in EPC were studied in 20 patients. Patients who fulfilled the criteria for EPC between the years 1985 and 1999 were included in this retrospective and prospective study. The mean age was 18 years (range 5 months-70 years). Eleven patients (55%) had Type 1 EPC and in the remaining nine (45%) patients there were features of Type 2 EPC. Among children Rasmussen's encephalitis and viral encephalitis were the commonest cause for EPC. Encephalitis and vascular aetiology were frequently observed in adults. Tuberculous meningitis and tuberculomas occurred evenly in both the groups. The cause was unknown in two cases. Focal EEG abnormalities commonly consisted of discrete spikes, sharp waves (or) slow wave activity and periodic lateralized epileptiform discharges. The mean duration of follow up was 9.6 months with a range between 1 month and 4 years. Cognitive decline, motor deficits and pharmacoresistance to drugs were significantly seen among children with Type 2 EPC. Patients with Type 1 EPC had mild impairment of functional status with good response to treatment. The long-term prognosis depends upon the underlying cause.

Aged↗
PubMed2002

Selection of ideal candidates for epilepsy surgery in developing countries.

In order to become cost-effective, epilepsy surgery centers in developing countries will have to achieve excellent results by selecting candidates destined to have a seizure-free outcome using locally available limited technology and expertise, without compromising on patient safety. Our experience illustrates that this goal can be accomplished by selecting patients, whose epileptogenic zone can be unquestionably established, based on history, magnetic resonance imaging, and interictal and ictal scalp electroencephalogram findings. Patients with mesial temporal lobe epilepsy, and those with circumscribed potentially epileptogenic lesions belong to this category. A stepwise approach by reserving more difficult to treat patients to later date as experience develops, or by referring them to a better-equipped center, will help each center to understand its capabilities and limitations and to move forward. It would be essential to work with and educate the local public and professionals, if the epilepsy surgery program in a developing region were to have a lasting impact, It is encouraging to note that, despite major challenges, in the last one-decade, several epilepsy centers in the developing world have not only successfully implemented epilepsy surgery programs, but also have produced results comparable to that from developed countries at a fractional cost.

Developing Countries↗
PubMed2002

Idiopathic hypertrophic cranial pachymeningitis.

Idiopathic hypertrophic cranial pachymeningitis is a rare form of fibrosing chronic inflammatory process of unknown etiology, which causes thickening of the intracranial dura mater. We present four patients with hypertrophic cranial pachymeningitis who presented with chronic headache and cranial nerve palsies. The diagnosis of idiopathic hypertrophic cranial pachymeningitis was based on neuroimaging findings of thickened enhancing dura, exclusion of known causes and histopathologic findings compatible with nonspecific inflammation in the meningeal biopsies. Corticosteroid therapy was effective in all cases in inducing a complete or partial remission of the neurologic symptoms and signs. We describe the clinical, radiological and pathological features of idiopathic hypertrophic cranial pachymeningitis and discuss the relationship of this entity with other inflammatory fibrosclerotic disorders to explain the pathogenesis. A high index of suspicion, prompt confirmation of the diagnosis by meningeal biopsy, and early institution and long-term maintenance of steroid therapy may help to prevent irreversible neurologic sequelae, especially blindness.

Adrenal Cortex Hormones↗