Daniel Bocchese Nora

An evaluation of gender, obesity, age and diabetes mellitus as risk factors for carpal tunnel syndrome

OBJECTIVES The aim of this study is to identify gender, high body mass index (BMI), age and diabetes mellitus (DM) as independent risk factors (RF) for carpal tunnel syndrome (CTS) and to analyse the strength of association of these factors, both globally and in individual subgroups. METHODS We performed a case-control study with 791 CTS cases and 981 controls. Patients were selected from those referred to nerve conduction studies and electromyography in 3 university hospitals and two private services. We calculated the odds ratio between the two groups to analyse the RF. Possible sources of bias were studied using stratified and multivariate analyses. RESULTS The mean BMI and age were greater in the case group than in the control. Female gender, BMI>30, age of 41-60 years and DM were significantly more frequent in the case group. Males tend to have a more severe CTS and DM was a significant RF for bilateral lesions. Stratified analysis showed female gender, obesity and age of 41-60 years as independent RF. DM, when stratified by BMI category, was not significantly associated with CTS. CONCLUSIONS Our study confirms that female gender, obesity and age are independent RF for CTS. DM may be a weak RF, especially among women.

What symptoms are truly caused by median nerve compression in carpal tunnel syndrome

OBJECTIVE This study aims to identify the symptoms, signs and distributions which are associated with neurophysiological carpal tunnel syndrome (N-CTS), defined by the finding of a median nerve lesion at the wrist through neurophysiologic studies, and to compare them with those of patients with sensory or motor complaints in the upper limbs whose electrophysiologic investigation did not show evidence of this syndrome. METHODS A cross-sectional study was performed, with prospective gathering of data, following a predetermined protocol. We included all patients older than 12 years who were referred for nerve conduction studies and electromyography of at least one of the upper limbs between August 2001 and January 2003. The patients answered a clinicoepidemiologic questionnaire and painted the areas in which they felt pain and those in which they felt paresthesia, and were also examined to test for classical signs CTS. RESULTS A neurophysiological diagnosis of CTS was reached in 1549 upper limbs (39%). Approximately 6% of the upper limbs with N-CTS and 16% of those without median nerve lesion do not have any hand or wrist symptoms (P<0.001). Paresthesia, pain, hand weakness and cramps were the symptoms statistically associated to N-CTS, with paresthesia being the one with the greatest power of association. This is usually felt in median innervations territory, and is frequently extended to the whole hand, but without association with N-CTS when felt in proximal region. CONCLUSIONS One concludes that the most characteristic manifestation of carpal tunnel syndrome (CTS) is paresthesia. Pain also occurs very frequently but it is less specific, and weakness, meanwhile, seems to have a low frequency. We believe that the variability in the clinical presentation of CTS is largely due to the presence of associated diseases and our results provide information which could help to better define the clinical criteria used in the diagnosis of this syndrome.

Clozapine, but not typical antipsychotics, correct P50 suppression deficit in patients with schizophrenia.

OBJECTIVE To find out if there is a difference in P50 suppression between patients using typical antipsychotic drugs and those using clozapine, as well as to confirm the findings of abnormal P50 suppression in patients with schizophrenia, when compared to healthy volunteers. METHODS Fifty patients with schizophrenia and 25 healthy volunteers were divided into 3 groups: group 1 - patients using typical antipsychotics; group 2 - patients using clozapine; group 3 - controls. Before the examination, all patients were interviewed by a psychiatrist using the Brief Psychiatry Rating Scale (BPRS). RESULTS The average S2/S1 ratio was 0.82+/-0.45 in group 1, 0.57+/-0.41 in group 2, and 0.44+/-0.27 in group 3 (P=0.003). Statistical analysis showed a significant difference when the results of group 1 were compared to those of groups 2 (P=0.045) and 3 (P=0.001). There was no significant difference between groups 2 and 3 (P=0.182). There was a significant difference in the S1-S2 difference only between groups 1 and 3 (P=0.007), but a non-significant trend towards a similar difference was found between groups 1 and 2 (P=0.067). There was no correlation between the BPRS values and any P50 parameter. CONCLUSIONS The suppression of P50 among patients using clozapine was significantly greater than that obtained in patients using typical antipsychotics. SIGNIFICANCE This study confirms, in a more evident way, the improvement of the suppression of P50 potential in schizophrenics using clozapine. Additionally, it discusses the physiopathological mechanism involved.

Hypocalcemic myopathy without tetany due to idiopathic hypoparathyroidism: case report

UNLABELLED Myopathy due to idiopathic hypoparathyroidism is very unusual. We report on a 30 years-old man referred with complaints of sporadic muscle pain and mild global weakness for 10 years. His physical examination showed normal strength in distal muscle and slightly weakness in the pelvic and scapular girdles with no atrophy. Deep muscle reflexes were slightly hypoactive. Trousseaus and Chvosteks signs were absent. He had bilateral cataract and complex partial seizures. His laboratory tests showed decreased ionised and total calcium and parathyroid hormone and increased muscle enzymes. EMG and muscle biopsy was compatible with metabolic myopathy. After treatment with calcium and vitamin D supplementation he showed clinical, neurophysiological and laboratorial improvement. IN CONCLUSION patients with muscle symptoms, even when non-specific and with normal neurological examination, should have serum calcium checked, as myopathy due to idiopathic hypoparathyroidism, even being rare, is treatable and easy to diagnose.

Visual-evoked potentials : Assessment of retrobulbar and peribulbar anesthesia

Purpose: To assess the effects of retrobulbar and peribulbar anesthesia on nerve function as detected by visual‐evoked potentials (VEPs). Setting: University hospital in southern Brazil. Methods: In a prospective study, 7 patients had peribulbar anesthesia and 9 had retrobulbar anesthesia for extracapsular cataract extraction. Visual‐evoked potentials with pattern reversal and flash stimulation were performed at least 1 month before and 1 month after surgery. Study participants did not have ocular pathology other than cataract. The Lens Classification System III was used to grade the opacities before surgery. Results: No significant difference was found between preoperative and postoperative evaluations in VEP flash and pattern‐reversal amplitude and latency in either group (P > .05). Postoperative amplitude and latency was not significantly different between the peribulbar and retrobulbar groups. Two cases in the peribulbar group had altered wave morphology without clinical manifestation postoperatively. All patients had a final best spectacle‐corrected visual acuity of 20/20. Conclusion: Block anesthetic procedures were safely used in cataract surgery, with no clinical sequelae to the optic nerve.

Evoked potentials for the evaluation of latent hepatic encephalopathy in pediatric liver transplant candidates

Background Visual evoked potentials (VEPs) and brain stem auditory evoked potentials (BAEPs) have been proposed as tools in the diagnosis of subclinical hepatic encephalopathy (HE). However, little information exists to determine their usefulness in pediatric patients. This study was undertaken to evaluate both methods in the detection of subclinical HE in pediatric liver transplant candidates. Methods VEPs and BAEPs were recorded in 15 pediatric liver transplant candidates with no clinical signs of HE. The wave latencies found in these examinations were then compared with those in 16 healthy controls of similar age. Laboratory data on liver function and electroencephalographic data from the patients were also recorded to examine their correlation with the evoked potentials results. Results No differences were found in the BAEP results between patients and controls. However, in the VEPs, the liver transplant candidates had significantly prolonged N1 (N75) latencies when compared with controls; no significant delay was found in the other waves. In contrast, among the children with liver disease, higher BAEP peak latencies correlated positively with electroencephalographic abnormalities, but this correlation was not observed in VEPs. Conclusions Evoked potentials might be of use in detecting alterations related to HE in children. However, further studies are necessary to determine their sensitivity and specificity in this situation.

Peripheral neuropathy in patients with hepatitis virus C infection in the Amazon region

INTRODUCTION Hepatitis virus C (HCV) infection is considered a health problem in the State of Acre localized in the Brazilian Amazon which has a prevalence rate of 5.9%. Peripheral neuropathy is a common extra-hepatic manifestation in patients with HCV. OBJECTIVE To determine the prevalence of peripheral neuropathies using clinical and neurophysiological parameters. METHOD A cross sectional study was performed in patients assisted by a specialized center of infectious diseases in the State of Acre. All patients completed a clinicoepidemiological questionnaire, physical examination and nerve conduction studies (NCS). RESULTS We studied 78 patients with mean age 45.5 years (range from 10 to 76 years), two thirds were male, 51% had at least 8 years of formal education and 96% lived in the capital city of Acre State. Roughly 34% of patients complained about paresthesias mainly in upper limbs. The NCS diagnosed multiple mononeuropathy in 11 (14.1%; IC95% 7.6-23.2) patients and carpal tunnel syndrome in 4 (5.1%) patients. CONCLUSION Subclinical involvement of peripheral nerves seems common in patients with HCV, with multiple mononeuropathy the main manifestation of nerve injury in this region as suggested by electrophysiological studies.

Modifications of the sympathetic skin response in workers chronically exposed to lead

The long-term effects of low-level lead intoxication are not known. The sympathetic skin response (SSR) was evaluated in a group of 60 former workers of a primary lead smelter, located in Santo Amaro, BA, Brazil. The individuals participating in the study were submitted to a clinical-epidemiological evaluation including questions related to potential risk factors for intoxication, complaints related to peripheral nervous system (PNS) involvement, neurological clinical examination, and also to electromyography and nerve conduction studies and SSR evaluation. The sample consisted of 57 men and 3 women aged 34 to 69 years (mean +/- SD: 46.8 +/- 6.9). The neurophysiologic evaluation showed the presence of lumbosacral radiculopathy in one of the individuals (1.7%), axonal sensorimotor polyneuropathy in 2 (3.3%), and carpal tunnel syndrome in 6 (10%). SSR was abnormal or absent in 12 cases, representing 20% of the sample. More than half of the subjects (53.3%) reported a history of acute abdominal pain requiring hospitalization during the period of work at the plant. A history of acute palsy of radial and peroneal nerves was reported by about 16.7 and 8.3% of the individuals, respectively. Mean SSR amplitude did not differ significantly between patients presenting or not the various characteristics in the current neurological situation, except for diaphoresis. The results suggest that chronic lead intoxication induces PNS damage, particularly affecting unmyelinated small fibers. Further systematic study is needed to more precisely define the role of lead in inducing PNS injury.