Antidyskinetic drug therapy for pediatric movement disorders

Neurometabolic disorders are treatable causes of dystonia

A broad range of rare inherited metabolic disorders can present with dystonia. For clinicians, it is important to recognize dystonic features, but it can be complicated by the mixed and complex clinical picture seen in many neurometabolic patients. Careful phenotyping is the first step towards the diagnosis of the underlying condition and subsequent targeted treatment, further supported by imaging, biochemical diagnostics and the availability of modern diagnostic techniques such as next generation sequencing. As several neurometabolic disorders are treatable causes of dystonia, these should have priority in the diagnostic process. In the symptomatic treatment of dystonia, several therapeutic options are available. Awareness for the occurrence and optimal treatment of dystonia and other movement disorders in neurometabolic conditions is important because these symptoms can have a substantial impact on the quality of life and daily functioning; this effect is not only exerted by the dystonia itself, but also by the frequently associated non-motor features. In this paper, the highlights and key concepts of neurometabolic forms of dystonia are discussed, with a focus on phenomenology, the diagnostic approach, the most important neurometabolic aetiologies, co-occurring non-motor features and therapeutic options.

Selection of treatment modalities in children with spastic cerebral palsy

The purpose of this report was to outline the various options currently used for treatment of spastic cerebral palsy (CP) and to discuss factors involved in selecting the appropriate treatment modalities for the individual child. In a review of the literature and his personal observations, the author presents an outline of treatment options and the criteria for using each. Therapeutic options include the following: physiotherapy; occupational therapy; oral spasmolytic and antidystonic drugs; botulinum toxin injections; orthopedic procedures; continuous infusion of intrathecal baclofen (ITB); selective dorsal rhizotomy (SDR); and selective peripheral neurotomy. The most commonly used neurosurgical procedures are ITB pump placement and SDR, and these are discussed in the most detail. The author's personal schema for assessment of the child to determine the nature of the hypertonia, the impact of the hypertonia, and the appropriate therapeutic intervention is presented. There are factors that help guide the optimal treatment modalities for the child with spastic CP. The treatment of these children is optimized in the setting of a multidisciplinary team.

A forward look at therapy for pediatric movement disorders

The mainstay of current therapy for pediatric movement disorders is oral symptomatic medication, unless a reversible etiology can be found. However, this approach is apt to pale in comparison with innovative strategies on the clinical forefront. Classical pharmacotherapy is restricted by the blood-brain barrier, which prevents access to the brain of potentially therapeutic molecules. Recent developments in molecular biotechnology include antibody-mediated drug release, feedback-responsive delivery systems, carrier-mediated transport, microspheres composed of polymers and liposomes, permeabilizers, and selective delivery to localized sites and vectors. Neuroprotective strategies for delivering neurotrophic factors and antiapoptotic and antioxidant molecules in neurodegenerative disorders are currently under study in clinical trials. Stem cell transplantation has great potential for tissue engineering and also as a carrier for gene therapy, although its use raises complex societal issues. These approaches, together with a plethora of transgenic knockout animal models of neurodegenerative disorders, offer real promise for a previously untreatable group of movement disorders.

Chloral hydrate for progressive myoclonus epilepsy: a new look at an old drug

This study demonstrates that chloral hydrate can be used to control daytime myoclonic exacerbations. It reports on four patients with progressive myoclonus epilepsy--three with Unverricht-Lündborg disease (EPM1) and one with progressive external ophthalmoplegia (PEO)--all of whom were taking more than one antiepileptic drug. Response to the liquid formulation was faster than response to the capsule and was preferred by the patients. The unusual feature was less than expected sedation or development of tolerance even at daily doses above 500 mg administered for years. Because chloral hydrate helped to improve quality of life, it should be made available to patients with progressive myoclonus epilepsy as adjunctive therapy. Recent evidence of interactions with various excitatory and inhibitory amino acid neurotransmitter-operated ion channels as a mechanism of action may provide insight into altered neurotransmission in progressive myoclonus epilepsy.

Gabapentin treatment in a child with delayed-onset hemichorea/hemiballismus

A 13-year, 6-month-old female was evaluated for subacute onset of left-sided hemichorea/hemiballismus, with an old, right parietal, cortical, and subcortical stroke as the presumed cause. Treatment with gabapentin was initiated, with good results at 6-month follow-up. Discussion of the differential diagnosis and evaluation of delayed-onset movement disorders in children and the mechanism of action of gabapentin is included.

Treatment of childhood myoclonus with botulinum toxin type A

Because of inadequate response to or intolerable side effects of oral medication, nine patients with segmental, generalized, and focal myoclonus were treated with intramuscular botulinum toxin type A. All patients were evaluated with neuroimaging, routine and limb-monitored electroencephalography, electromyography, evoked potentials and appropriate biochemical studies. Patients were aged 2 to 22 years, with duration of myoclonus from 1 month to 10 years. Multiple medication trials included antiepileptic drugs, benzodiazepines, tryptophan, L-dopa/carbidopa, baclofen, and dantrolene. Patients were injected with botulinum toxin in their affected area with electromyographic guidance to affected muscles with different doses (8 to 20 units/kg), except two patients who were injected with 32 and 45 units/kg, respectively, at 4- to 8-month intervals. One patient did not complete botulinum toxin treatment because of subjective weakness, although there were virtually no side effects reported in patients completing therapy. Patients reported a dramatic reduction in painful myoclonus. In addition, patients exhibited improved functional skills, as demonstrated by markedly improved use of affected extremities and improvements in ambulation. One patient, who was nonambulatory prior to treatment, was able to walk afterward. Long-term benefits could be related to higher dosage used or negative feedback effect.

An aggressive approach to limb dystonia: a case report

A 15-year-old boy presented with a severe fluctuating foot and ankle dystonia resulting from a basal ganglia insult at the age of 4. This followed an embolic event related to an undiagnosed prolapsed mitral valve. Functionally, the patient was ambulatory with rocker bottom crutches and an ankle-foot orthosis, but there were periods of up to a year when pain and increased dystonic deformity required him to use a wheelchair. A new orthotic was made nearly every month because the orthotist could find no material that would withstand his tone without breaking, yet he could not ambulate without one. Multiple interventions, including biofeedback, contrast baths, stretching and strengthening, oral lioresal (Baclofen), diazepam (Valium), benztropine mesylate (Cogentin), carbidopa-levodopa (Sinemet), carbamazepine (Tegretol), and injections of botulism toxin (BOTOX) were tried, all with minimal effects. Amputation was recommended, based on anatomic and functional considerations. The patient and his family adjusted well to this decision, although not all orthopedists and therapists adjusted easily to the choice. The patient is now functionally independent with a prosthesis and has a normal teenage lifestyle for the first time.

Oral pharmacotherapy for the movement disorders of cerebral palsy

Movement disorders are a well-recognized feature of some patients with cerebral palsy and often require treatment. However, treatments have been symptomatic and empiric, and there have been few pharmacologic studies. The major movement disorders in cerebral palsy are dystonia and the hyperkinesias choreoathetosis and myoclonus. They may occur in combination, often accompanied by spasticity and sometimes by epilepsy. Some drugs are useful treatments for all of these problems, but others may improve one while worsening another. Pitfalls in management include not diagnosing metabolic/degenerative disorders, which may mimic cerebral palsy, or not recognizing reversible complications of cerebral palsy, which may exacerbate symptoms. This review attempts to summarize empiric drug use and recommendations for therapy, drug studies in extrapyramidal cerebral palsy, and prospects for new drugs or models for the problem. Many new pharmacologic agents are available for study in cerebral palsy. Better methods of detecting basal ganglia injury after perinatal injury in asymptomatic infants may allow early intervention in the biologic process of recovery and adaptation.