João Aris Kouyoumdjian

Peripheral nerve injuries: a retrospective survey of 456 cases.

This 16‐year retrospective study reports the data on 456 consecutive patients with 557 peripheral nerve injuries (PNIs) between 1989 and 2004. Most patients were men (74%) and the mean age was 32.4 years. In 83% of cases the PNIs were isolated; combined lesions most commonly involved the ulnar and median nerves. Upper‐limb PNIs occurred in 73.5% of cases; the ulnar nerve was most often injured, either singly or in combination. Vehicle accidents affecting the brachial plexus or radial, sciatic, facial, and peroneal nerves were the most common cause of injury. Penetrating trauma commonly affected the ulnar and median nerves; falls and gunshot wounds frequently affected the ulnar, radial, and median nerves; and sports injuries, particularly soccer, affected mainly the peroneal and tibial nerves. More than half of the brachial plexus lesions after vehicular accidents were from motorcycle crashes. Muscle Nerve, 2006

Evaluation of age, body mass index, and wrist index as risk factors for carpal tunnel syndrome severity

To determine the role of personal variables as risk factors for carpal tunnel syndrome (CTS) and their relationship to severity of nerve conduction abnormality, we studied 210 consecutive symptomatic CTS patients and 320 controls subjects without CTS symptomatology or known systemic disorders. The CTS group was classified according to the severity of nerve conduction changes. The risk factors for CTS and its severity were assessed by means of univariate and multivariate analysis. Presence of CTS was significantly related to increase of body mass index (BMI) and wrist index. More severe nerve conduction abnormalities were associated with greater age and wrist index but not with higher BMI.

Reference jitter values for concentric needle electrodes in voluntarily activated extensor digitorum communis and orbicularis oculi muscles.

The aim of this study was to estimate normal jitter in voluntarily activated extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles using a disposable concentric needle electrode (CNE). The EDC of 67 normal subjects (22 males and 45 females, mean age 35.5 ± 10.2 years) and the OOc of 50 normal subjects (13 males and 37 females, mean age 37.9 ± 9.6 years) were studied. Jitter values were expressed as the mean consecutive difference (MCD) of 20 potential pairs. The mean MCD for EDC was 23.6 ± 3.1 μs (upper 95% confidence limit [CL]: 29.7 μs). The mean MCD of all potential pairs (n = 1340) was 23.5 ± 7.3 μs (95% CL: 38.2 μs). The mean MCD for the 18th highest value was 31.4 ± 4.9 μs (95% CL: 41.2 μs). The mean MCD for OOc was 24.7 ± 3.1 μs (95% CL: 31.0 μs). The mean MCD of all potential pairs (n = 1000) was 24.7 ± 7.1 μs (95% CL: 39.0 μs). The mean MCD for the 18th highest value was 32.7 ± 4.1 μs (95% CL: 40.9 μs). Our reported CNE jitter values obtained during voluntary activation represent the largest series currently available. The suggested practical limit in the EDC for mean MCD was 30 μs and for outliers was 42 μs, and in the OOc for mean MCD was 31 μs and 41 μs for outliers. The present study confirms that CNE can be used to assess jitter values, although certain precautions must be taken. Muscle Nerve 37: 694–699, 2008

Body mass index and carpal tunnel syndrome

Carpal tunnel syndrome (CTS) has been correlated to body mass index (BMI) increase. The present study was done in a Brazilian population to compare BMI values in the following groups: first, CTS vs. controls subjects, and, second CTS groups of increasing median sensory latency (MSL). According to MSL>/=3.7 ms (wrist-index finger, 14 cm), median/ulnar sensory latency difference>/=0.5 ms (ring finger, 14 cm) or median palm-to-wrist (8 cm) latency>/=2.3 ms (all peak-measured), 141 cases (238 hands) had CTS confirmation. All were symptomatic; previous surgery and polyneuropathy were excluded; mean age 50.3; 90.8% female. Controls subjects (n=243; mean age 43.0; 96. 7% female) and CTS cases had BMI calculated (kg/m2). Controls subjects had a mean BMI of 25.43+/-4.80 versus 28.38+/-4.69 of all CTS cases, a statistically significant difference (p < 0.001). The CTS groups of increasing MSL severity do not show additional increase in BMI (28.44 for incipient, 28.27 for mild, 28.75 for moderate and 29.0 for severe). We conclude that CTS cases have a significant correlation with higher BMI when compared to controls subjects; however, higher BMI do not represent a statistically significant increasing risk for more severe MSL.

Concentric needle jitter on stimulated Orbicularis Oculi in 50 healthy subjects

OBJECTIVES The aim of this study was to estimate the jitter parameters in healthy controls in stimulated Orbicularis Oculi (OOc) muscle using concentric needle electrode (CNE). METHODS Fifty healthy subjects, 13 males and 37 females (21-56 years, mean age of 38±9.2 years) were studied. The zygomatic branch of facial nerve was stimulated with a bar electrode. Jitter was expressed as the mean consecutive difference (MCD). Filter settings 1000 Hz-10 kHz. RESULTS The mean MCD from individual studies (n=50, Gaussian distribution) was 21.5±1.99 μs (median=21 μs), ranging from 17.8 to 26 μs (upper limit, 97.5%, 25.5 μs). The mean and median MCD from all potentials (n=1500, non-Gaussian distribution) were 21.6 and 21 μs, ranging from 7.1 to 39 μs (upper limit, 97.5%, 33.4 μs). CONCLUSIONS Suggested practical limits in the OOc for mean MCD was 26 μs and for outliers 34 μs. SIGNIFICANCE Stimulation jitter recordings with CNE could be used in practice but borderline findings should be judged with great caution until larger database obtained with uniform setting available.

Fatal rhabdomyolysis after acute sodium monensin (Rumensin®) toxicity: case report

Myoglobinuria or rhabdomyolysis occurs when myoglobin escapes into the blood and then into the urine after acute muscle necrosis. It can be a serious medical condition leading to renal failure and death. There are many causes including exertion, crush syndromes, ischaemia, metabolic disorders, exogenous toxins and drugs, heat stroke and hereditary disorders such as malignant hyperthermia. We report the case of a 17 year-old boy who developed myoglobinuria, renal failure and death 11 days after ingesting sodium monensin, possibly with the intention of developing muscles. Sodium monensin, the active principle of Rumensin(R), is a dietary additive used as a growth promoter for confined cattle. There are no previous reports of human intoxication. Accidental or experimental sodium monensin intoxication in animals produces similar findings to those seen in this case.

Concentric needle single fiber electromyography: Comparative jitter on voluntary-activated and stimulated Extensor Digitorum Communis

OBJECTIVE To compare the jitter values in voluntarily activated (v-CNE) and stimulated (s-CNE) techniques for Extensor Digitorum Communis muscle using a disposable concentric needle electrode (CNE). Quantifying jitter using a CNE in conjunction with a stimulated technique has not been reported previously. METHODS Forty-one normal subjects were studied, 15 male and 26 female with a mean age of 34.1+/-10.7 years (19-55). The jitter values were expressed as the mean consecutive difference (MCD) of 20 analyzed potential pairs using v-CNE and 30 isolated potentials using s-CNE. RESULTS The mean MCD (n=41) was 23.0+/-2.8 micros for v-CNE and 18.2+/-2.2 micros for s-CNE. The mean jitter of all recorded potentials was 22.9+/-6.7 micros for v-CNE (n=820) and 18.3+/-5.2 micros for s-CNE (n=1230). Upper limits for the 18th (v-CNE) and 27th highest (s-CNE) MCD were 38.9 and 30 micros, respectively (95% confidence limit). The jitter decrease in s-CNE compared to v-CNE was 1:0.79. CONCLUSIONS Our findings of the jitter values using CNE were similar to other published reports using the voluntarily activated technique; however, these are the first described for the stimulated technique using CNE. SIGNIFICANCE The present study confirms that CNE can be used for the stimulated jitter acquisition and measurement, although certain precautions must be taken regarding signal quality, e.g., observing minimal summation.

Acidentes ofidicos causados por Bothrops moojeni: correlação do quadro clínico com o tamanho da serpente

During a period of 19 months (March 1986-September 1987), 22 cases of snake bites caused by Bothrops moojeni in São José do Rio Preto, São Paulo (South-east Brazil) were studied. The animals have their length measured and two groups were constituted: group I - 9 cases with length between 30 and 53 cm and group II - 13 cases with length between 80 and 147 cm. Our results revealed: 1. the local effects--pain and swelling--were frequently mild in group I; 2 - non-clotting blood (bed-side test) occurred in two groups, a little more frequently in group I; 3. local complications--necrosis, compartment syndrome and infection--occurred in more than a half and exclusively in group II, in spite of larger and faster antivenom therapy. We have concluded that larger Bothrops moojeni produced great increment in swelling, necrosis and infection and mild decrement in coagulation action.During a period of 19 months (March 1986 - September 1987), 22 cases of snake bites caused by Bothrops moojeni in Sao Jose do Rio Preto, Sao Paulo (South-east Brazil) were studied. The animals have their lenght measured and two groups were constituted: group I - 9 cases with lenght between 30 and 53 cm and group II - 13 cases with lenght between 80 and 147 cm. Our results revealed: 1. the local effects - pain and swelling - were frequently mild in group I; 2 - non-clotting blood (bed-side test) occured in two groups, a little more frequently in group I; 3. local complications - necrosis, compartment syndrome and infection - occured in more then a half and exclusively in group II, in spite of larger and faster antivenom therapy. We have concluded that larger Bothrops moojeni produced great increment in swelling, necrosis and infection and mild decrement in coagulation action.

Carpal tunnel syndrome: age, nerve conduction severity and duration of symptomatology

Median sensory and motor distal latencies (SDL/MDL) were correlated with age and duration of symptomatology in 1498 carpal tunnel syndrome (CTS) patients (17-90 years old, 87.6% female). Patients were distributed in four groups according to distal latencies severity. There was an increase in age as long as SDL/MDL became more severe, ranging from 47.5 to 67 years old (mild to severe-absence potentials in both hands groups, respectively). There was a less dramatic increase in duration of complaints as long as SDL/MDL became more severe, ranging from 12 to 30.7 months (mild to severe-absence potentials in both hands groups, respectively). Aging correlates more positively than duration of complaints with severity of SDL/MDL in CTS. The effects of increasing median blockage in CTS are more severe as long as patients become older regardless duration of symptomatology.

Concentric needle single fiber electromyography: normative jitter values on voluntary activated Extensor Digitorum Communis

Single fiber electromyography (SFEMG) is the most sensitive clinical neurophysiological test for neuromuscular junction disorders, particularly myasthenia gravis. Normal values for jitter obtained with SFEMG electrode have been published, but there are few publications for concentric needle electrode (CNE). The aim of this study was to discuss the possibilities to analyse the jitter in CNE recordings and to get normal values of jitter for voluntary activated Extensor Digitorum Communis using disposable CNE. Fifty normal subjects were studied, 16 male and 34 female with a mean age of 37.1+/-10.3 years (19-55). The jitter values of action potentials pairs of isolated muscular fibers were expressed as the mean consecutive difference (MCD) after 20 analysed potential pairs. The mean MCD (n=50) obtained was 24.2+/-2.8 micros (range of mean values in each subject was 18-31). Upper 95% confidence limit is 29.8 micros. The mean jitter of all potential pairs (n=1000) obtained was 24.07+/-7.30 micros (range 9-57). A practical upper limit for individual data is set to 46 micros. The mean interpotential interval (MIPI) was 779+/-177 micros (range of individual mean values was 530-1412); there were no potentials with impulse blocking. The present study confirms that CNE is suitable for jitter analysis although certain precautions must be mentioned. Our findings of jitter values with CNE were similar to some other few reports in literature.