Myoclonus and epilepsies

Top of the basilar artery embolic stroke and neonatal myoclonus

Cerebellar stroke has been virtually unreported in the living newborn infant. A term newborn male weighing 3380g at birth suffered myoclonic seizures within 24 hours of birth by spontaneous vaginal delivery. Apgar scores were 3 and 4 at 1 and 5 minutes. Myoclonus persisted for 9 days, responding poorly to step-up anticonvulsant treatment including lidocaine, midazolam, and clonazepam. Imaging documented arterial ischaemic stroke within the left posterior cerebral and both superior cerebellar arteries, compatible with top of the basilar artery stroke. There was no electrographic correlate for the seizures. Disturbed oscillation within the dentato-rubro-olivary circuitry was the likely mechanism. The probable cause was embolism from an in-utero-onset inferior caval vein thrombosis. At 22 months the child was sitting unsupported. Scores on the Bayley Scales of Infant Development II were equivalent to those of a 12-month/year-old. He showed ataxic motor behaviour. Embolism can cause neonatal top of the basilar artery stroke, which may present with myoclonus due to cerebellar injury.

Pathophysiology of pediatric movement disorders

Pediatric movement disorders constitute a relatively small cluster of symptoms that can be associated with many different underlying diseases. To provide effective treatment, it is essential to understand the relationship between etiology and clinical expression. This article reviews the recent literature on several common pediatric movement disorders, including spasticity, dystonia, chorea, myoclonus, bradykinesia, and tics, and it discusses current models of physiology that may help link the cellular pathology of specific diseases to the expression of clinical symptoms.

Myoclonus in childhood

The term "myoclonus" sounds esoteric, yet it is part of our normal physiology, occurring as a muscle jerk on drowsiness or falling asleep, during rapid eye movement (REM) sleep, and as hiccoughs. Myoclonus is also a developmental feature of the human nervous system, comprising some of the earliest fetal movements. In pathologic settings, myoclonus may be the only neurologic abnormality, as in essential myoclonus, but more often it is one symptom of a larger neurologic problem. The vast etiologic spectrum of symptomatic myoclonus can be bewildering, but defining the underlying problem may provide the opportunity to develop specific therapies. Otherwise, treatment is merely symptomatic. The approach to the patient should be to verify the nature of the movement disorder and establish a specific etiologic diagnosis. A battery of neurophysiologic, neuroradiologic, and other laboratory studies is needed to localize the origin of the myoclonus and identify causative lesions. Drug treatment is largely empiric but must be systematic and aimed at restoring activities of everyday living. Unlike in epilepsies, in myoclonus multiple drugs usually must be combined to attain functional improvement.

West syndrome and other infantile epileptic encephalopathies--Indian hospital experience

Children with infantile epileptic encephalopathies comprising 3.5% of the Pediatric Neurology Clinic registrations in a tertiary care hospital were retrospectively analyzed. Data were retrieved from case records and analyzed for seizure semiology, prenatal and perinatal insults, developmental status and relevant investigations. The various therapeutic modalities and their influence on spasm frequency, long-term development and final seizure status were compared. The two primary outcome variables analyzed included final seizure status and developmental outcome. Of the 94 infantile epileptic encephalopathies, West syndrome was the commonest (55.3%), of which two thirds were symptomatic. Etiological factors were prenatal in 66.6% and perinatal in 33.3%. The initial response to ACTH was good in 54.5% with subsequent relapse in 27.8% and for prednisolone was 52.9 and 44.4%, respectively, compared to 25.3% spasms control with conventional antiepileptic drugs. Disease category of infantile epileptic encephalopathies evolved in 4, i.e. early myoclonic encephalopathy to West syndrome 1, early infantile epileptic encephalopathy to West syndrome 1, West syndrome to Lennox-Gastaut syndrome 2. Psychomotor retardation was seen in 88.2%, with 16.1% having normal development at onset of spasms. Microcephaly was associated with delayed development but did not influence final seizure outcome. Final seizure outcome was poor in children with delayed development at onset (adjusted odds ratio [OR] = 4), delay in diagnosis >12 months (OR = 2.27) and in children with Lennox-Gastaut syndrome (OR = 4.75). ACTH/prednisolone and antiepileptic treatment versus antiepileptics alone showed a good final seizure response in 36.6% versus 20%. Development on follow up was delayed in children with initial psychomotor retardation (OR = 23.4) and abnormal electroencephalogram (OR = 7.46). Perinatal factors constituted one third of symptomatic West syndrome. The use of ACTH/corticosteroids resulted in good initial spasm control though final seizure outcome and development were unaffected. Prednisolone had similar response to ACTH in spasm control but higher subsequent relapse rate. Vigabatrin was useful though often unaffordable. The identification of a neurometabolic etiology, though uncommon, has significant therapy implications. Delay in diagnosis was common and negatively influenced final seizure outcome.

West syndrome and other infantile epileptic encephalopathies--Indian hospital experience

Children with infantile epileptic encephalopathies comprising 3.5% of the Pediatric Neurology Clinic registrations in a tertiary care hospital were retrospectively analyzed. Data were retrieved from case records and analyzed for seizure semiology, prenatal and perinatal insults, developmental status and relevant investigations. The various therapeutic modalities and their influence on spasm frequency, long-term development and final seizure status were compared. The two primary outcome variables analyzed included final seizure status and developmental outcome. Of the 94 infantile epileptic encephalopathies, West syndrome was the commonest (55.3%), of which two thirds were symptomatic. Etiological factors were prenatal in 66.6% and perinatal in 33.3%. The initial response to ACTH was good in 54.5% with subsequent relapse in 27.8% and for prednisolone was 52.9 and 44.4%, respectively, compared to 25.3% spasms control with conventional antiepileptic drugs. Disease category of infantile epileptic encephalopathies evolved in 4, i.e. early myoclonic encephalopathy to West syndrome 1, early infantile epileptic encephalopathy to West syndrome 1, West syndrome to Lennox-Gastaut syndrome 2. Psychomotor retardation was seen in 88.2%, with 16.1% having normal development at onset of spasms. Microcephaly was associated with delayed development but did not influence final seizure outcome. Final seizure outcome was poor in children with delayed development at onset (adjusted odds ratio [OR]=4), delay in diagnosis >12 months (OR=2.27) and in children with Lennox-Gastaut syndrome (OR=4.75). ACTH/prednisolone and antiepileptic treatment versus antiepileptics alone showed a good final seizure response in 36.6% versus 20%. Development on follow up was delayed in children with initial psychomotor retardation (OR=23.4) and abnormal electroencephalogram (OR=7.46). Perinatal factors constituted one third of symptomatic West syndrome. The use of ACTH/corticosteroids resulted in good initial spasm control though final seizure outcome and development were unaffected. Prednisolone had similar response to ACTH in spasm control but higher subsequent relapse rate. Vigabatrin was useful though often unaffordable. The identification of a neurometabolic etiology, though uncommon, has significant therapy implications. Delay in diagnosis was common and negatively influenced final seizure outcome.