Multiple sclerosis in childhood: understanding and caring for children with an "adult" disease.

Multiple sclerosis (MS) is rare in childhood but may occur more frequently than originally believed. In light of the complex nature of MS, the expanding availability of new MS treatments, and the developmental needs of pediatric patients, multidisciplinary care of pediatric patients with MS is a necessity. Our review of MS in childhood aims to increase the awareness of neuroscience nurses about MS in children and adolescents, and to expand the knowledge of pediatric nurses concerning this "adult" disease. Our experience in developing a multidisciplinary pediatric MS clinic that addresses both health and developmental needs of children with MS is presented and discussed. The nurse's role in the care of these children and their families through assessment, support, education, advocacy, referral and coordination of care is emphasized.

Amplitudes of sural and radial sensory nerve action potentials in orthodromic and antidromic studies in children.

Several previous studies of adults have reported that the amplitudes of the sural and superficial radial nerve action potentials (SN and SRN SNAP respectively) are larger with antidromic than with orthodromic recordings. However, this difference has not been documented in children. This study evaluated the amplitudes of SN and SRN SNAPs obtained with antidromic and orthodromic recordings in children with and without neuropathy and compared these data with findings in adults. The SN or SRN or both of 10 neurologically normal children, 6 children with neuropathy and 7 healthy adults were studied with surface stimulation and recording. The position of the stimulating and recording electrodes for the orthodromic recordings was the reverse of that for the antidromic recordings. Peak-to-peak SNAP amplitudes were measured and analyzed. The mean of the SRN SNAP amplitude was significantly higher with the antidromic than the orthodromic technique for the first and third groups (p < 0.05). The mean SN SNAP amplitude was higher in the three groups, but not statistically significant when the data for the children and adult normal groups were combined and reanalyzed (p < 0.05). Consistent responses were obtained with both techniques. However, the antidromic technique was superior to the orthodromic technique because of the greater amplitude of responses. We recommend the use of the antidromic technique because of its greater amplitudes, ease of use and potential reduction of discomfort to the patient.

Somatosensory evoked potentials and nerve conduction studies in patients with Guillain-Barré syndrome.

Somatosensory evoked potentials, F-waves, and nerve conduction studies (NCS) were performed to determine their usefulness in detecting electrophysiologic abnormalities in 23 children in the acute stage of Guillain-Barré syndrome. The studies were performed on average 8.3 days after the onset of neurological symptoms, before the period of maximal weakness. All patients had at least one abnormal test. Somatosensory evoked potentials (SEP) showed most abnormalities: 91% abnormal recordings with posterior tibial nerve (PTN) stimulation and 68% with median nerve (MN) stimulation. The nerve conduction velocities were abnormal in 76% and 67% with PTN and MN stimulation, respectively. The F-waves were abnormal in 66% (PTN) and 56% (MN). The SEP studies were helpful in detecting proximal and central conduction abnormalities in 26% of patients, and they were more sensitive in detecting an abnormality when compared with F-wave recordings. Furthermore, in one patient with normal NCS and F-waves the prolonged lumbar potential-P35 conduction time of the PTN-SEP was the only abnormality found. SEP can detect an abnormality and thus support the clinical diagnosis of Guillain-Barré syndrome in the acute stage when the results of more conventional tests are inconclusive.

VEPs in normal full-term and premature neonates: longitudinal versus cross-sectional data.

VEPs have been shown to change with CNS maturation in children, yet few studies had documented maturational changes in the premature infant. Using LED goggles, VEPs were studied in 75 neurologically normal infants of 22-42 weeks gestational age (GA) within the first 3 days of life. Twenty of these (22-32 weeks GA) were also followed longitudinally. The 22-23 week GA neonates had no identifiable waves. In all infants greater than 24 weeks a large negative wave is seen with a latency around 300 msec (N300). After 27 weeks GA a late positive wave was present (P400), but with more variable latency and morphology. Between 30 and 35 weeks GA a small positive wave (P200) was seen in over one-third of the neonates; this component was present in all infants greater than 36 weeks GA. The consistency of the N300 across the ages studied suggests that it might arise from the basilar dendrites in the visual cortex, which are well developed by 24 weeks GA and undergo relatively little further development between 24 weeks and term. The P200 is suggested to arise from the apical dendrites which develop in the last trimester, explaining the emergence of P200 after 30 weeks GA. The infants followed longitudinally showed the same components, emerging in the same order, but with more rapid development (particularly of P200) compared to the cross-sectional studies. These data suggest that there are differences in the maturation of the visual system in the extrauterine versus intrauterine environment.

Prognostic utility of visual evoked potentials in term asphyxiated neonates.

The prognosis for term infants with birth asphyxia is variable and does not correlate well with the acute clinical state. Diagnostic tools such as electroencephalography or imaging techniques have not been satisfactory predictors of outcome. Visual evoked potentials (VEPs) have changed acutely in birth asphyxia and may provide information for long-term prognosis. We studied VEPs serially in 25 term infants with documented birth asphyxia. The VEPs were classified into three categories: normal, mildly abnormal, or severely abnormal, and then compared to each infant's acute clinical state and outcome at age six months. Eight of the nine infants with normal or mildly abnormal VEPs were normal when examined subsequently. All the patients with severely abnormal VEPs died, or suffered severe neurologic sequelae. The VEPs demonstrated good correlation with neurodevelopmental outcomes in infants with birth asphyxia and may be useful prognostically.

Endogenous and pharmacological mechanisms for the regulation of human platelet cytosolic free Ca2+.

Because they inhibit the processes that promote elevation of [Ca2+]i and augment the processes that promote removal of Ca2+ from the cytosol, receptor antagonists, agents that mimic or elevate cAMP, cGMP or 1,2-Diacylglycerol (DG), and both inorganic and organic Ca2+ channel blockers can be considered to act as 'Ca2+ antagonists' on human platelets. Agonist-induced elevation of [Ca2+]i is associated with phosphoinositide hydrolysis. Unlike agents that mimic or elevate cAMP, cGMP or DG, receptor antagonists and organic Ca2+ influx, mobilisation of internal Ca2+ and inositol lipid hydrolysis. Lanthanides apparently inhibit only Ca2+ influx. Thus La3+ but not Verapamil or Diltiazem block receptor-operated Ca2+ channels on human platelets. The endogenous processes that promote extrusion or sequestration of cytosolic Ca2+ may be augmented by cAMP, cGMP, DG and by Ca2+. DG, via activation of protein kinase C, may serve as a bi-directional regulator of platelet reactivity.