Handbook of clinical neurology
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Anti-NMDA receptor encephalitis is a newly characterized severe neuroautoimmune syndrome with a progressive, clinical course. Most often seen in females, it usually begins with a prodromal phase suggestive of an acute or subclinical upper respiratory tract infection that lasts for up to 2 weeks. This is followed by a psychotic and seizure phase in which the child may rapidly develop seizures, behavioral changes, and, less commonly in children, psychiatric symptoms, resulting in frequent misdiagnoses. ⋯ Relapses in children may be multiple and occur in 20-25% of cases. Recovery is slow and may take 3 years or longer. Even so, the child may not always regain its premorbid level of health.
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Stroke is the major cause of long-term disability worldwide, with impaired manual dexterity being a common feature. In the past few years, noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have been investigated as adjuvant strategies to neurorehabilitative interventions. These NIBS techniques can be used to modulate cortical excitability during and for several minutes after the end of the stimulation period. ⋯ Differential modulation of cortical excitability in the affected and unaffected hemisphere of patients with stroke may induce plastic changes within neural networks active during functional recovery. The aims of this chapter are to describe results from these proof-of-principle trials and discuss possible putative mechanisms underlying such effects. Neurophysiological and neuroimaging changes induced by application of NIBS are reviewed briefly.
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Epilepsies associated with inborn errors of metabolism (IEM) represent a major challenge. Seizures rarely dominate the clinical presentation, which is more frequently associated with other neurological symptoms, such as hypotonia and/or cognitive disturbances. Although epilepsy in IEM can be classified in various ways according to pathogenesis, age of onset, or electroclinical presentation, the most pragmatic approach is determined by whether they are accessible to specific treatment or not. ⋯ Folinic acid-dependent seizures are allelic with pyridoxine dependency. Incompletely treatable IEMs include pyridoxal phosphate, serine, and creatine deficiencies. The main IEMs that present with epilepsy but offer no specific treatment are nonketotic hyperglycinemia, mitochondrial disorders, sulfite oxidase deficiency, ceroid-lipofuscinosis, Menkes disease, and peroxisomal disorders.
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Invasive stimulation of the motor (precentral) cortex using surgically implanted epidural electrodes is indicated for the treatment of neuropathic pain that is refractory to medical treatment. Controlled trials have demonstrated the efficacy of epidural motor cortex stimulation (MCS), but MCS outcome remains variable and validated criteria for selecting good candidates for implantation are lacking. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive approach that could be used as a preoperative tool to predict MCS outcome and also could serve as a therapeutic procedure in itself to treat pain disorders. ⋯ The most studied target is the precentral cortex, but other targets, such as the prefrontal and parietal cortices, could be of interest. The analgesic effects of cortical stimulation relate to the activation of various circuits modulating neural activities in remote structures, such as the thalamus, limbic cortex, insula, or descending inhibitory controls. In addition to the treatment of refractory neuropathic pain by epidural MCS, new developments of this type of strategy are ongoing, for other types of pain syndrome and stimulation techniques.
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The diagnosis of brain death should be based on a simple premise. If every possible confounder has been excluded and all possible treatments have been tried or considered, irreversible loss of brain function is clinically recognized as the absence of brainstem reflexes, verified apnea, loss of vascular tone, invariant heart rate, and, eventually, cardiac standstill. This condition cannot be reversed - not even partly - by medical or surgical intervention, and thus is final. ⋯ Generally, the concept of brain death has been accepted by all major religions. But patients' families may have different ideas and are mostly influenced by cultural attitudes, traditional customs, and personal beliefs. Suggestions are offered to support these families.