Transcranial magnetic stimulation and acoustic trauma or hearing loss in children.

Transcranial magnetic stimulation is a non-invasive method used to assess motor function in humans; however, some reports suggest it may cause internal ear damage (cochlear). Eighteen patients with normal auditory function (ages 2 months to 16 years, mean 6.8 years), two medical doctors and two technicians who performed the studies were tested with brain stem auditory evoked potentials, otoacoustic emissions, acoustic reflex and a pure tone audiometric and logoaudiometric test when possible, before and after transcranial magnetic stimulation for central motor conduction studies in different neurological conditions. All the tests were repeated two weeks and two months later. Patients had no auditory protection nor history of seizures. Motor evoked potentials and silent periods were recorded from the right abductor pollicis brevis and the first dorsal interosseous muscles at rest and during weak voluntary contraction when possible. A mean of 48 transcranial magnetic stimulations with 50%-75% Tesla intensity were used. Natural logarithmic transformation of latency and amplitude data had a normal distribution. There were no significant differences in auditory function testing.

Contribution of the MHC class II antigens to the etiology of infantile spasm in Mexican Mestizos.

PURPOSE: Infantile spasms (ISs) are age-dependant epileptic seizures, which may be flexor, extensor, lightning or nods, or mixed. The aim of this study was the analysis of genetic factors within the human leukocyte antigen (HLA) complex associated with ISs. METHODS: Sixty-five patients diagnosed according to the established international criteria were compared with 229 healthy individuals; all of them were Mexican Mestizos. Five families were also analyzed (seven affected and five healthy sibs); HLA class I and class II antigens were typed using the standard microlymphocytotoxicity methods. RESULTS: The findings showed female gender preference (2:1). Two thirds were symptomatic, and prevalent seizures were of mixed type (67%). A strong association with HLA-DR17 was detected in the IS group (pc < 0.01; OR = 3.6; EF = 0.20). DR17 was also found increased in the symptomatic patients (p = 0.009; OR = 3.16) and in those with other types of seizures (p = 0.001; OR = 2.0). Conversely, HLA-DQ6 was significantly decreased (pc < 0.002; PF = 0.37) in the total and in the symptomatic groups (p < 0.01). Haplotype linkage was not confirmed in the families; however, those with more than one affected sib shared at least one haplotype. CONCLUSIONS: These findings suggest the contribution of DR locus to the susceptibility and the participation of DQ region in the resistance to IS. Severity seems also to be influenced by HLA-DR17, and therefore class II typing may be a helpful tool for disease prognosis.

Brain death in children: clinical, neurophysiological and radioisotopic angiography findings in 125 patients.

The objective of this study was to determine the main clinical, neurophysiological and angiographic findings in brain death (BD) in children seen at the Instituto Nacional de Pediatría, a third-level facility in Mexico City, between 1991 and 1996. The following variables were retrospectively analyzed: sex, age, etiology, associated morbidity, duration of stay in hospital, and the results of two of three confirmatory studies (electroencephalogram, evoked potentials, radioisotopic angiography). In all, 125 patients were studied 78 male, median age 2 years (range: 18 days to 17 years)[. The most frequent etiology was infection (34%); 57% of the children developed associated morbidity. In 111 of 122 patients electrocerebral silence was observed; 100 of 107 had brain stem and somatosensory evoked potentials affording conclusive evidence of BD; and 83 of 90 patients had a positive radioisotopic angiography indicating BD. In 76 patients all three confirmatory studies were performed: for 15 there was at least one false-negative test result. Our age cohort showed a predominance of children less than 2 years old. BD etiologies in developing countries differ from those reported in developed countries.

Early detection of neurological manifestations in achondroplasia.

Achondroplasia (ACh) is the most frequent bone dysplasia. The mode of inheritance is autosomal dominant. The incident of neurological complications ranges between 20% and 47%; frequently the symptoms are subtle but are due to such serious conditions as cervicomedullary compressive syndromes, syringomyelia or hydrocephalus; thus, the early identification of this disorder is very important. We made a prospective study of 39 patients (20 female, 19 male) with ACh; their ages ranged from 3 months to 17 years (mean 4 years and 6 months). All patients had hypotonia and psychomotor delay; 3 had recurrent apnea, 1 developed radicular syndrome and 1 had leg paresthesias. The CT scan was normal in 5, 20 had cortical atrophy and 18 communicating hydrocephalus; we identified foramen magnum abnormalities in 28 patients, and reduced craniocervical junction with cervicomedullary compression in 6. Myelography and myelotomography demonstrated spinal compression in 12 patients. The MRI showed cervicomedullary infarct in 1, syringomyelia in 2 and diastematomyelia in 1. The somatosensory evoked responses (SSER) were very useful in the early identification of brain stem and spinal abnormalities. We concluded that the neurological manifestations of pediatric patients with ACh are frequent and very important, demanding comprehensive clinical evaluation even in asymptomatic patients, especially those with severe hypotonia or SSER alterations.

Clinical pharmacokinetics of albendazole in children with neurocysticercosis.

The pharmacokinetics of albendazole sulphoxide, the main metabolite of albendazole, were studied in eight children with brain cysticercosis. Albendazole was given as a single oral dose of 15 mg per kg body weight (Zentel suspension; Smith Kline & Beecham, Philadelphia, PA). Blood samples were taken during 24 h and analyzed by high performance liquid chromatography. Plasma levels showed great interindividual variation. Maximum plasma levels for albendazole sulphoxide ranged from 0.2-1.0 microg/mL. A double peak was found in four children. The half-life for albendazole sulphoxide was from 2.3-8.3 hours and mean residence time values were from 5. 1-13.6 hours. These values are shorter than those found in adults. The results suggest that when treating children with neurocysticercosis, albendazole should be administered three times a day rather than twice daily as is currently done in Mexico.

Neurocysticercosis in children. Clinical experience in 122 patients.

Cysticercosis is the most frequent parasitic disease of the central nervous system in the world and is endemic in such developing countries as Mexico. There is insufficient information about neurocysticercosis in children. The purpose of this study was to collect information on the main social factors associated with neurocysticercosis, the clinical picture, diagnosis and treatment, and the final outcome in 122 Mexican children. The ages of the patients ranged from 14 months to 17 years, with a mean of 8 years; 51 male (41.8%) and 71 female (51.8%) patients were seen; half of these patients (61) lived in well-urbanized areas; the parents of 77 families (57.3%) had only an elementary school grade average, and 46 (37.7%) lived in close proximity to animals. The most common features were seizures, intracranial hypertension and learning disabilities. The diagnosis of neurocysticercosis was supported by computed tomography or magnetic resonance imaging studies and cerebrospinal fluid analysis. The treatment was varied, with anti-convulsives, steroids, and albendazole, and only 8 patients underwent ventriculo-peritoneal shunts for hydrocephalus. The follow-up ranged from 6 months to 5 years; 90 patients became asymptomatic; 6 developed refractory epilepsy; 14, learning disabilities; and 10, a chronic type of the disease with repeated episodes of intracranial hypertension; 2 died because of chronic arachnoiditis.

A novel mitochondrial DNA point mutation associated with mitochondrial encephalocardiomyopathy.

A novel mitochondrial DNA (mtDNA) mutation at position nt 4320 in the tRNA(Ile) gene was associated with severe encephalopathy in a 7-month-old infant, who died of intractable hypertrophic cardiomyopathy. The mutation was present in heteroplasmic fashion (88%) in muscle and fulfills accepted criteria for pathogenicity. This is the fourth pathogenic mutation identified in this gene, which appears to be a "hotspot" for deleterious mutations affecting the heart. This report adds to the evidence of genetic heterogeneity in hypertrophic cardiomyopathies.

Characterization of a 5025 base pair mitochondrial DNA deletion in Kearns-Sayre syndrome.

We characterized a mitochondrial DNA deletion in a patient with Kearns-Sayre syndrome. Southern blot hybridization showed that 86 to 93% of the mitochondrial genome harbored a 5.0 kb deletion. The percentage of affected genomes is higher than in previously described cases. Direct sequencing of the breakpoint region revealed that the deletion extended 5025 bp from nt 10,050 in the tRNA Gly gene to nt 15,076 in the cytochrome b gene, thus 30% of the total mitochondrial genome was lost by this deletion. A pair of extremely short mirror sequences flanking the mitochondrial DNA breakpoints were identified. These flanking sequences differ from previously published consensus 'hot-spots', known to give rise to deletions in human mitochondrial DNA.

[Status epilepticus in children. Study of 70 cases]. / Estado epiléptico en niños. Estudio de 70 casos.

We presented the experience at the Emergency Unit of the National Institute of Pediatrics with children with Status Epilepticus (SE). This series studied 70 patients, the greatest frequency was seen among infants (55%), followed by preschool children (17%). The most frequent type of SE was generalized tonic clonic (54%) also being the most critical. The simple partial status or epilepsia partialis continua was found to be another frequent variety. In newborns babies the most common type of SE was generalized tonic. Sixty percent originated as acute process, their main causes were central nervous infections, ischemic-hypoxic encephalopathy, intracranial hemorrhages and intoxications. The remaining 40% were due to chronic processes, the most important was secondary epilepsy. Among these children the main cause was the irregular use of antiepileptic drugs. Other factors were intercurrent infections with fever, head trauma and hyponatremia. Only 12.8% of the cases were idiopathic. Fifteen percent of the SE were successfully treated with diazepam; 44% with phenytoin plus phenobarbital, in 34.2% we used generalized anesthesia with thiopental. In 33% of the acute cases os SE there were sequelae, there were nine deaths (12.8%) all of them with serious illness of the central nervous system.