Maria da Penha Ananias Morita

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.

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.

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.

Wrist and palm indexes in carpal tunnel syndrome

According to median sensory latency >/= 3.7 ms (wrist-index finger [WIF], 14 cm), median/ulnar sensory latency difference to ring finger >/= 0.5 ms (14 cm) or median midpalm (8 cm) latency >/= 2.3 ms (all peak-measured), 141 Brazilian symptomatic patients (238 hands) have CTS confirmation. Wrist ratio (depth divided by width, WR) and a new wrist/palm ratio (wrist depth divided by the distance between distal wrist crease to the third digit metacarpophalangeal crease, WPR) were measured in all cases. Previous surgery/peripheral neuropathy were excluded; mean age 50.3 years; 90.8% female. Control subjects (486 hands) have mean age 43.0 years; 96.7% female. The mean WR in controls was 0.694 against 0.699, 0.703, 0.707 and 0.721 in CTS groups of progressive WIF severity. The mean WPR in controls was 0.374 against 0.376, 0.382, 0.387 and 0.403 in CTS groups of WIF progressive severity. Both were statistically significant for the last two groups (WIF > 4.4 ms, moderate, and, WIF unrecordable, severe). BMI increases togetherwith CTS severity and WR. It was concluded that both WR/WPR have a progressive correlation with the severity of CTS but with statistically significance only in groups moderate and severe. In these groups both WR and BMI have progressive increase and we believe that the latter could be a risk factor as important as important WR/WPR.

Myasthenia gravis in children: analysis of 18 patients

Myasthenia gravis (MG) in childhood is rare comprising 10 to 20 % of all myasthenic patients. We studied 18 patients with MG whose first symptoms started from 1 to 12 years of age, followed at the Department of Neurology of the UNIFESP-EPM, from January 1983 to August 1997. There were 10 girls and 8 boys (1.2:1). Eleven patients (61%) presented moderate or severe generalized disease and 4 (22%) had at least one myasthenic crisis. EMG with supramaximal repetitive nerve stimulation was diagnostic in 8 (47%) out of 17 patients, and chest CT was normal in 14 patients. Seropositivity to acetylcholine receptor antibodies was found in 81.6% (9 out of 11 tested) and the levels had no relation to clinical severity. Nine out of 16 patients (56%) worsened with pyridostigmine alone and were treated with prednisone. Four out of those nine continued worsening despite steroids and were subjected to thymectomy (all showed thymic lymphoid follicular hyperplasia). Three patients (75%) improved markedly after thymectomy and one (25%) worsened, eventually getting better with intravenous immunoglobulin and oral azathioprine. MG treatment, using all resources available, has to be individualized for each child.

Paralisia periódica: estudo anátomo-patológico do músculo esquelético de 14 pacientes

Periodic paralysis is a rare disease, characterized by transient weakness associated with abnormal levels of serum potassium. Muscle biopsy may show a wide range of abnormalities, vacuoles being more specifically linked to the disease. We analysed 17 muscle biopsies from 14 patients with periodic paralysis (14 hypokalemic, 2 hyperkalemic). All of them showed at least one histological abnormality. Fourteen specimens showed vacuoles that were peripheral, single, frequent and preferentially found in type I fibers. Frequency or severity of attacks did not correlate with the presence of vacuoles but those were more easily found in patients with long term disease. Ten biopsies showed tubular aggregates, specially on the patients with frequent crises or long term disease. A second biopsy was done in three patients and in two we observed a worsening of the histopathologic picture. One patient manifested interictal weakness with evident myopathic changes on the muscle biopsy. Nonspecific changes were found in variable degrees in 15 biopsies. Our study shows that vacuoles and tubular aggregates are frequent changes in periodic paralysis and therefore helpful for the diagnosis. Important myopathic findings in the muscle biopsy suggest a permanent myopathy which probably develops after severe crises or long term disease.Periodic paralysis is a rare disease, characterized by transient weakness associated with abnormal levels of serum potassium. Muscle biopsy may show a wide range of abnormalities, vacuoles being more specifically linked to the disease. We analysed 17 muscle biopsies from 14 patients with periodic paralysis (14 hypokalemic, 2 hyperkalemic). All of them showed at least one histological abnormality. Fourteen specimens showed vacuoles that were peripheral, single, frequent and preferentially found in type I fibers. Frequency or severity of attacks did not correlate with the presence of vacuoles but those were more easily found in patients with long term disease. Ten biopsies showed tubular aggregates, specially on the patients with frequent crises or long term disease. A second biopsy was done in three patients and in two we observed a worsening of the histopathologic picture. One patient manifested interictal weakness with evident myopathic changes on the muscle biopsy. Nonspecific changes were found in variable degrees in 15 biopsies. Our study shows that vacuoles and tubular aggregates are frequent changes in periodic paralysis and therefore helpful for the diagnosis. Important myopathic findings in the muscle biopsy suggest a permanent myopathy which probably develops after severe crises or long term disease.

A novel myopathy-associated mitochondrial DNA mutation altering the conserved size of the tRNAGln anticodon loop

We report a novel mitochondrial DNA alteration in a 12-year-old boy with myopathy. We identified a single nucleotide insertion (an adenine) in the mitochondrial tRNA-glutamine gene. This addition of an additional adenine in a polyadenine stretch (at mitochondrial DNA positions 4366-4369), alters the length of the evolutionary conserved anticodon loop from seven to eight bases. The nt-4370 addition was heteroplasmic and was abundant in the patients muscle. Lower proportions of mutated mitochondrial DNA were observed in skin fibroblasts, but were below detectable levels in white blood cells. A muscle biopsy of the patient showed ragged red fibers and an unusually high percentage of cytochrome c oxidase-deficient fibers (89%). The pathogenicity of the mutation was also evident by the fact that fibers harboring lower levels of the mutation showed normal cytochrome c oxidase activity. The insertion in the anticodon loop of tRNA(Gln) gene identified in our patient may provide a unique tool to study protein synthesis in human mitochondria.

Comparison of nerve conduction techniques in 95 mild carpal tunnel syndrome hands

Electrodiagnosis of carpal tunnel syndrome (CTS) were prospectively studied in 95 hands. The following techniques were studied in all hands and when at least one abnormal value was found (onset-measured), it was included on results: 1. wrist-index finger latency (WIF), abnormal > or = 2.8 ms, 140 mm; 2. palm-wrist latency (PW), abnormal > or = 1.8 ms, 80 mm; 3. comparison median/ulnar palm-wrist latency (CPW), abnormal > or = 0.4 ms; 4. comparison median/ulnar latency, wrist-ring finger (CMU), abnormal > or = 0.5 ms, 140 mm; 5. comparison median/radial latency, wrist-thumb (CMR), abnormal > or = 0.4 ms, 100 mm. All 95 CTS hands selected have the WIF < or = 3.5 ms (mild CTS). We found the CMR (97.8%) technique the most sensitive for mild CTS electrodiagnosis and the only comparative method with all potentials recordable when compared to CPW (88.4%), PW (84.2%), CMU (72.6%) and WIF (68.4%).

Análise da expressão do colágeno VI na distrofia muscular congênita

Congenital muscular dystrophy (CMD) composes a group of disorders characterized by hypotonia and muscular weakness noticed in the first year of life. The Ullrichs form is characterized by proximal joint contractures and distal hiperextensibility. About 40% of these patients present mutations in one of the genes that codify the sub-units of the collagen VI protein (COL6), producing total or partial deficiency of the protein expression. We analyzed, through immunohistochemistry, the expression of COL6 in muscle fragments of 50 patients with CMD; 20 of them presented merosin expression deficiency. We identified 4 cases with total COL6 deficiency (8% of the total), representing 13% of the cases with normal merosin expression. The histological findings of patients with deficiency of COL6 were indistinguishable from other forms of CMD, but milder than that abnormalities observed in merosin deficient patients. In three COL6 deficient patients were observed hypotonia and weakness in the neonatal period, delayed of motor milestones, muscular retractions of knees and elbows, distal joint hiperextensibility and congenital hip dislocation (two patients). One patient lost the ability to walk; and one died due to respiratory problems. The analysis of COL6 expression, as well as merosin expression, in the muscle tissue from CMD patients, can be important for identification and phenotypic characterization of different CMD subtypes.

Usefulness of additional nerve conduction techniques in mild carpal tunnel syndrome

This study was done to assess the percentage of abnormality in additional nerve conduction techniques after normal median distal latency (routine) in mild carpal tunnel syndrome (CTS). Bilateral nerve conduction studies were carried out in 116 consecutive symptomatic CTS patients (153 hands). Mild cases were based on normal routine (< 3.7 ms, peak-measured, 14 cm) and at least one technique abnormal of the following: sensory median-radial difference (MR); sensory median-ulnar difference (MU4); mixed palm median-ulnar difference (MUP); median palm latency (PW); and motor median distal latency (MDL). After normal cut-off values for routine, 3.1 to 3.6 ms (< 3.7 ms), we found an abnormal MR, ranging from 86.6 to 93.4%, followed by MU4 (40 to 81.7%), MUP (20 to 71.2%), PW (0 to 41.1%), and MDL (0 to 19.6%). The most frequent abnormal association were MR plus MU4 in 90.1%, followed by MR plus MUP and MU4 plus MUP. The most frequent abnormal additional nerve conduction technique for mild CTS electrodiagnosis was MR, followed by MU4 and MUP. Percentage of MR abnormality was very high regardless of the median routine latency cut-off (< 3.1 to < 3.6 ms).