Vedantam Rajshekhar

Proposed diagnostic criteria for neurocysticercosis.

Neurocysticercosis is the most common helminthic infection of the CNS but its diagnosis remains difficult. Clinical manifestations are nonspecific, most neuroimaging findings are not pathognomonic, and some serologic tests have low sensitivity and specificity. The authors provide diagnostic criteria for neurocysticercosis based on objective clinical, imaging, immunologic, and epidemiologic data. These include four categories of criteria stratified on the basis of their diagnostic strength, including the following: 1) absolute—histologic demonstration of the parasite from biopsy of a brain or spinal cord lesion, cystic lesions showing the scolex on CT or MRI, and direct visualization of subretinal parasites by funduscopic examination; 2) major—lesions highly suggestive of neurocysticercosis on neuroimaging studies, positive serum enzyme-linked immunoelectrotransfer blot for the detection of anticysticercal antibodies, resolution of intracranial cystic lesions after therapy with albendazole or praziquantel, and spontaneous resolution of small single enhancing lesions; 3) minor—lesions compatible with neurocysticercosis on neuroimaging studies, clinical manifestations suggestive of neurocysticercosis, positive CSF enzyme-linked immunosorbent assay for detection of anticysticercal antibodies or cysticercal antigens, and cysticercosis outside the CNS; and 4) epidemiologic—evidence of a household contact with Taenia solium infection, individuals coming from or living in an area where cysticercosis is endemic, and history of frequent travel to disease-endemic areas. Interpretation of these criteria permits two degrees of diagnostic certainty: 1) definitive diagnosis, in patients who have one absolute criterion or in those who have two major plus one minor and one epidemiologic criterion; and 2) probable diagnosis, in patients who have one major plus two minor criteria, in those who have one major plus one minor and one epidemiologic criterion, and in those who have three minor plus one epidemiologic criterion.

Current Consensus Guidelines for Treatment of Neurocysticercosis

SUMMARY Taenia solium neurocysticercosis is a common cause of epileptic seizures and other neurological morbidity in most developing countries. It is also an increasingly common diagnosis in industrialized countries because of immigration from areas where it is endemic. Its clinical manifestations are highly variable and depend on the number, stage, and size of the lesions and the hosts immune response. In part due to this variability, major discrepancies exist in the treatment of neurocysticercosis. A panel of experts in taeniasis/cysticercosis discussed the evidence on treatment of neurocysticercosis for each clinical presentation, and we present the panels consensus and areas of disagreement. Overall, four general recommendations were made: (i) individualize therapeutic decisions, including whether to use antiparasitic drugs, based on the number, location, and viability of the parasites within the nervous system; (ii) actively manage growing cysticerci either with antiparasitic drugs or surgical excision; (iii) prioritize the management of intracranial hypertension secondary to neurocysticercosis before considering any other form of therapy; and (iv) manage seizures as done for seizures due to other causes of secondary seizures (remote symptomatic seizures) because they are due to an organic focus that has been present for a long time.

Treatment of neurocysticercosis: Current status and future research needs

Here we put forward a roadmap that summarizes important questions that need to be answered to determine more effective and safer treatments. A key concept in management of neurocysticercosis is the understanding that infection and disease due to neurocysticercosis are variable and thus different clinical approaches and treatments are required. Despite recent advances, treatments remain either suboptimal or based on poorly controlled or anecdotal experience. A better understanding of basic pathophysiologic mechanisms including parasite survival and evolution, nature of the inflammatory response, and the genesis of seizures, epilepsy, and mechanisms of anthelmintic action should lead to improved therapies.

Taenia solium taeniosis/cysticercosis in Asia: epidemiology, impact and issues

Several reports of patients with cysticercosis from many countries in Asia such as India, China, Indonesia, Thailand, Korea, Taiwan and Nepal are a clear indicator of the wide prevalence of Taenia solium cysticercosis and taeniosis in these and other Asian countries. However, epidemiological data from community based studies are sparse and available only for a few countries in Asia. Cysticercosis is the cause of epilepsy in up to 50% of Indian patients presenting with partial seizures. It is also a major cause of epilepsy in Bali (Indonesia), Vietnam and possibly China and Nepal. Seroprevalence studies indicate high rates of exposure to the parasite in several countries (Vietnam, China, Korea and Bali (Indonesia)) with rates ranging from 0.02 to 12.6%. Rates of taeniosis, as determined by stool examination for ova, have also been reported to range between 0.1 and 6% in the community in India, Vietnam, China, and Bali (Indonesia). An astonishingly high rate of taeniosis of 50% was reported from an area in Nepal populated by pig rearing farmers. In addition to poor sanitation, unhealthy pig rearing practices, low hygienic standards, unusual customs such as consumption of raw pork is an additional factor contributing to the spread of the disease in some communities of Asia. Undoubtedly, cysticercosis is a major public health problem in several Asian countries effecting several million people by not only causing neurological morbidity but also imposing economic hardship on impoverished populations. However, there are wide variations in the prevalence rates in different regions and different socio-economic groups in the same country. It is important to press for the recognition of cysticercosis as one of the major public health problems in Asia that needs to be tackled vigorously by the governments and public health authorities of the region.

Management of Neurosurgical Patients with Hyponatremia and Natriuresis

The main objective of our study was to evolve a practical management protocol for neurosurgical patients with hyponatremia and natriuresis, based on their blood volume status and hematocrit. Twenty-one patients with hyponatremia and natriuresis and 3 control patients were studied. Patients with hyponatremia were categorized on the basis of their hematocrit, central venous pressure, and total blood volume. Group A consisted of patients with hypovolemia and anemia (16 patients); Group B patients had hypovolemia but no anemia (5 patients); Group C included those with hypervolemia (0 patients). Patients in Groups A and B received isotonic saline (> 50 ml/kg/d) and oral salt (12 g/d). Additionally, those in Group A were transfused with 500 ml of whole blood. The end points in the study were 72 hours after entry or two consecutive serum sodium values of > 130 mEq/L, whichever was earlier. Hyponatremia was corrected in all the patients within 72 hours (1 patient, < 24 h; 13 patients, < 48 h; and 7 patients, < 72 h). We conclude that most neurosurgical patients with hyponatremia and natriuresis have hypovolemia, with or without anemia. Fluid and salt replacement and a blood transfusion rather than fluid restriction often results in the correction of the hyponatremia. Our findings offer indirect evidence to support the hypothesis that in most of these patients, hyponatremia is caused by cerebral salt wasting syndrome, rather than the syndrome of inappropriate secretion of antidiuretic hormone.

Active epilepsy as an index of burden of neurocysticercosis in Vellore district, India.

Objective: To determine the contribution of neurocysticercosis (NCC) to the causation of active epilepsy (AE) in a south Indian community. Methods: We conducted a door-to-door survey of 50,617 people between the ages of 2 and 60 years in a rural (38,105 people) and urban setting (12,512 people) in the Vellore district of the south Indian state of Tamil Nadu to identify patients with AE. Patients with AE were investigated with a contrast-enhanced CT scan and serologic study using enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. Results: We identified 194 patients with AE. The prevalence of AE was 3.83 per 1,000 people, with the prevalence in the urban clusters more than twice that in the rural clusters (6.23 vs 3.04 per 1,000) (p < 0.0001). A diagnosis of NCC was made in 46 (28.4%) of the 162 patients undergoing a CT scan, and EITB was positive in 21 (13%) patients. Overall, 55 (34%) patients were diagnosed with NCC (11 definitive NCC and 44 probable NCC). There was no significant difference in the prevalence of NCC causing AE in the urban (1.28 per 1,000) and rural (1.02 per 1,000) communities. Conclusions: NCC is the cause of nearly one-third of all cases of AE in both the urban and rural regions. Extrapolating our results to the country as a whole leads to an estimated disease burden of 1 million patients in India with AE attributable to NCC.

Validation of diagnostic criteria for solitary cerebral cysticercus granuloma in patients presenting with seizures

Objective ‐ To evaluate a set of clinical and computed tomographic (CT) criteria (previously described by us) to predict the diagnosis of a solitary cerebral cysticercus granuloma (SCCG) at initial presentation, in patients presenting with seizures. Material and methods ‐ The diagnostic criteria were applied prospectively to patients presenting with seizures and solitary lesion on the CT scan. The clinical diagnostic criteria were as follows: seizures should be the presenting complaint; there should be no evidence of persistent raised intracranial pressure, progressive neurological deficit or an active systemic disease. The CT diagnostic criteria were: evidence of a solitary contrast enhancing lesion measuring 20 mm or less in its maximal dimension without a shift of the midline structures due to the surrounding oedema. A diagnosis of SCCG was made only when all the clinical and CT criteria were fulfilled. Over a period of 36 months, we managed 401 patients presenting with seizures and a solitary mass on the CT scan; 215 met the criteria for the diagnosis of an SCCG. Results ‐ Of the 215 patients initially diagnosed to have an SCCG, 197 were ultimately determined to have that diagnosis (true positive diagnosis) while 16 were excluded because of lack of follow‐up CT assessment. Two of the 215 patients with the initial diagnosis of an SCCG subsequently had histological diagnosis of a secondary metastasis and a pyogenic abscess (false positive diagnosis). Our set of diagnostic criteria for SCCG had a sensitivity of 99.5%; specificity of 98.9%; a positive predictive value of 99%; and a negative predictive value of 99.5%. The likelihood ratios for the positive and negative tests were 92.99 and 0.005 respectively. Conclusions ‐ Our diagnostic criteria help in not only accurately identifying an SCCG but also in differentiating it from a solitary tuberculoma and other brain masses. However, confirmation of the diagnosis of an SCCG is only obtained at follow‐up evaluation and therefore careful clinical and CT re‐evaluation is essential in all patients initially diagnosed to have an SCCG.

Changes in cervical spine curvature after uninstrumented one- and two-level corpectomy in patients with spondylotic myelopathy.

OBJECTIVEWe studied changes in the cervical spine curvature in patients with cervical spondylotic myelopathy who underwent one- or two-level central corpectomy and iliac bone grafting without the use of instrumentation. METHODSCurvature of the fused segment and of the whole cervical spine was evaluated on preoperative and follow-up x-rays in 93 patients (30 underwent one-level corpectomy, and 63 underwent two-level corpectomy). In 59 patients, the changes in the cervical spine curvature were studied using one follow-up x-ray; in the other 34 patients, the changes were studied on x-rays obtained at two or more follow-up visits. The sagittal alignment of the fused segment was categorized as lordotic (>+5 degrees), straight (+5 to −5 degrees) or kyphotic (>−5 degrees). The whole spine curvature also was recorded as lordotic, straight, or kyphotic. RESULTSAt a mean follow-up of 22.2 months (range, 6–71 mo), there was a mean change of −10.4 degrees in the segmental curvature (P < 0.001). The fused segment sagittal alignment also worsened (lordotic angles becoming straight or kyphotic and straight angles becoming kyphotic) in 44 patients (47%)(P < 0.001). However, serial studies in 34 patients (mean first and last follow-ups, 11.9 and 30.8 mo, respectively) did not demonstrate significant worsening of the kyphotic angle or the sagittal alignment over time (P = 0.9). Whole spine curvature worsened in 33 (35%) of the 93 patients (P < 0.001); serial studies did not reveal a significant change (P = 0.9). Patients improved in their functional status from a preoperative mean Nurick grade of 2.9 (range, 1–5) to a follow-up mean Nurick grade of 1.5 (range, 0–4) (P < 0.001). Patients with a kyphotic change in their whole spine curvature (n = 33) and those without such change (n = 60) had a similar functional outcome (mean change in Nurick grade, 1.5 and 1.4, respectively). CONCLUSIONCervical spine curvature tended to undergo a kyphotic change at the fused segment in 47% of patients and a kyphotic change of the whole spine curvature in 35% of patients who underwent one- or two-level uninstrumented central corpectomy. This kyphotic change in the cervical spine, which stabilizes within 1 year after surgery, is not progressive, and it does not affect neurological outcome in these patients.

Revised diagnostic criteria for neurocysticercosis

BACKGROUND A unified set of criteria for neurocysticercosis (NCC) has helped to standardize its diagnosis in different settings. METHODS Cysticercosis experts were convened to update current diagnostic criteria for NCC according to two principles: neuroimaging studies are essential for diagnosis, and all other information provides indirect evidence favoring the diagnosis. Recent diagnostic advances were incorporated to this revised set. RESULTS This revised set is structured in absolute, neuroimaging and clinical/exposure criteria. Absolute criteria include: histological confirmation of parasites, evidence of subretinal cysts, and demonstration of the scolex within a cyst. Neuroimaging criteria are categorized as major (cystic lesions without scolex, enhancing lesions, multilobulated cysts, and calcifications), confirmative (resolution of cysts after cysticidal drug therapy, spontaneous resolution of single enhancing lesions, and migrating ventricular cysts on sequential neuroimaging studies) and minor (hydrocephalus and leptomeningeal enhancement). Clinical/exposure criteria include: detection of anticysticercal antibodies or cysticercal antigens by well-standardized tests, systemic cysticercosis, evidence of a household Taenia carrier, suggestive clinical manifestations, and residency in endemic areas. Besides patients having absolute criteria, definitive diagnosis can be made in those having two major neuroimaging criteria (or one major plus one confirmative criteria) plus exposure. For patients presenting with one major and one minor neuroimaging criteria plus exposure, definitive diagnosis of NCC requires the exclusion of confounding pathologies. Probable diagnosis is reserved for individuals presenting with one neuroimaging criteria plus strong evidence of exposure. CONCLUSIONS This revised set of diagnostic criteria provides simpler definitions and may facilitate its more uniform and widespread applicability in different scenarios.

Brainstem Glioma: Comparative Study of Clinico-Radiological Presentation, Pathology and Outcome in Children and Adults

Summary Although the clinical and imaging features and behaviour of brain stem gliomas in children are well documented, similar data are not available, for adults. We have carried out a retrospective study, on 101 consecutive patients (71 children and 30 adults) with a histologically verified brain stem glioma. Duration of symptoms, clinical features, imaging characteristics, histopathology and outcome were specifically compared in children and adults with brain stem glioma. Peak incidence was in the first decade in children and in the third and fourth decades in adults. Mean duration of symptoms before admission was 9.7 months in adults and 3.6 months in children (P<0.001). There were no significant differences in the clinical features between adults and children. Imaging characteristics revealed no major differences except that diffuse hypodense lesions involving the whole brainstem accounted for 41.2% of the lesions in children and only 11.1% of adults (P<0.001). A stereotactic biopsy was performed in 92 patients and an open biopsy or partial excision in 9 patients. Histopathological examination showed that the majority of gliomas were diagnosed as grade II astrocytomas in both groups. Survival was significantly shorter in children when compared to adults (P<0.01). While the tumour grade was a significant factor in predicting survival in adults, in children it did not correlate with outcome. Therefore, determination of the grade of a brain stem glioma may be of prognostic significance in adult patients.