MRI findings in people with epilepsy and nodding syndrome in an area endemic for onchocerciasis: an observational study

Background

Onchocerciasis has been implicated in the pathogenesis of epilepsy. The debate on a potential causal relationship between Onchocerca volvulus and epilepsy has taken a new direction in the light of the most recent epidemic of nodding syndrome.

Objective

To document MRI changes in people with different types of epilepsy and investigate whether there is an association with O. volvulus infection.

Methods

In a prospective study in southern Tanzania, an area endemic for O. volvulus with a high prevalence of epilepsy and nodding syndrome, we performed MRI on 32 people with epilepsy, 12 of which suffered from nodding syndrome. Polymerase chain reaction (PCR) of O. volvulus was performed in skin and CSF.

Results

The most frequent abnormalities seen on MRI was atrophy (twelve patients (37.5%)) followed by intraparenchymal pathologies such as changes in the hippocampus (nine patients (28.1%)), gliotic lesions (six patients (18.8%)) and subcortical signal abnormalities (three patients (9.4%)). There was an overall trend towards an association of intraparenchymal cerebral pathologies and infection with O. volvulus based on skin PCR (Fisher''s Exact Test p=0.067) which was most pronounced in children and adolescents with nodding syndrome compared to those with other types of epilepsy (Fisher''s Exact Test, p=0.083). Contrary to skin PCR results, PCR of CSF was negative in all patients.

Conclusion

The observed trend towards an association of intraparenchymal cerebral pathological results on MRI and a positive skin PCR for O. volvulus despite negative PCR of CSF is intriguing and deserves further attention.     

Contemporary Role of Systematic Prostate Biopsies: Indications,Techniques, and Implications for Patient Care

Context

Prostate cancer (PCa) screening to detect early stage PCa has resulted in increased identification of small-volume, low-grade PCa, many of which meet criteria for clinically indolent disease. Nevertheless, there remains some degree of underdetection of high-risk PCa in substantial numbers of men despite current diagnostic strategies.

Objective

To discuss the contemporary role of prostate biopsy (PB), focusing on the indications, techniques, and limitations of current PB techniques and evolving techniques affecting patient care.

Evidence acquisition

A comprehensive Medline search was performed using the medical subject heading search terms prostate cancer, detection, prostate biopsy, significant cancer, and diagnosis, with restriction to the English language. Emphasis was given to publications within the past 5 yr.

Evidence synthesis

Because abnormal digital rectal examination (DRE) and prostate-specific antigen (PSA) tests alone lack specificity for cancer, there is no universal indication for PB. This lack has inspired exploration for a cancer-specific biomarker and prediction tools such as risk calculators. Indication for biopsy should involve a balance between the underdiagnosis of high-risk cancers and the potential risks for the overdetection of clinically insignificant cancers as well as biopsy-related morbidity. Evidence supports the inclusion of laterally directed cores during transrectal ultrasound (TRUS) PB in addition to the traditional sextant pattern, which significantly improves cancer detection without a demonstrable increase in morbidity. These data indicate that such PB templates, typically 12 cores, represent the optimal template in initial PB. Optimised techniques and templates for repeat PB remain controversial. However, debate continues regarding indications, sampling number, and location as well as on the potential of modern image-guided approaches or three-dimensional (3D) mapping biopsy in this unique setting. Additional limitations of repeat PB techniques include associated procedural risks if general anaesthesia is required and inherent sampling errors of template-based techniques that are not targeted to the specific tumour site.

Conclusions

Current data support the utility of extended PB templates for initial TRUS PB intended to detect clinically significant PCa. Repeat PB in the setting of prior negative PB on the grounds of clinical suspicion or for risk-stratified approaches to management of low risk PCa requires balancing overdetection of low-risk cancer with the potential to miss significant cancer. Several options, including modern image-guided targeting, biomarker development, transrectal saturation PB, and 3D template mapping PB, are changing the clinical paradigms for evaluation and management. Evidence to support adopting approaches other than the current established standards should be tested through appropriately designed prospective studies.     

Primary Immunodeficiency Diseases in Latin America: The Second Report of the LAGID Registry

This is the second report on the continuing efforts of LAGID to increase the recognition and registration of patients with primary immunodeficiency diseases in 12 Latin American countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Honduras, Mexico, Panama, Paraguay, Peru, Uruguay, and Venezuela. This report reveals that from a total of 3321 patients registered, the most common form of primary immunodeficiency disease was predominantly antibody deficiency (53.2%) with IgA deficiency reported as the most frequent phenotype. This category was followed by 22.6% other well-defined ID syndromes, 9.5% combined T- and B-cell inmunodeficiency, 8.6% phagocytic disorders, 3.3% diseases of immune dysregulation, and 2.8% complement deficiencies. All countries that participated in the first publication in 1998 reported an increase in registered primary immunodeficiency cases, ranging between 10 and 80%. A comparison of the estimated minimal incidence of X-linked agammaglobulinemia, chronic granulomatous disease, and severe combined immunodeficiency between the first report and the present one shows an increase in the reporting of these diseases in all countries. In this report, the estimated minimal incidence of chronic granulomatous disease was between 0.72 and 1.26 cases per 100,000 births in Argentina, Chile, Costa Rica, and Uruguay and the incidence of severe combined immunodeficiency was 1.28 and 3.79 per 100,000 births in Chile and Costa Rica, respectively. However, these diseases are underreported in other participating countries. In addition to a better diagnosis of primary immunodeficiency diseases, more work on improving the registration of patients by each participating country and by countries that have not yet joined LAGID is still needed. Latin American Group for Primary Immunodeficiency Diseases