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Biomedical subjects

R O Robinson

Publications and source records attributed to R O Robinson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Molybdenum cofactor deficiency-phenotypic variability in a family with a late-onset variant.

In a family with molybdenum cofactor deficiency, the onset in the index case was delayed until 1 year of age, when the patient presented with an episode of lethargy and inconsolable crying culminating in a seizure. By 17 months she showed mild motor delay, regression in language skills, and feeding difficulties. Progressive global deterioration followed, associated with sustained irritability, dystonic posturing, and further seizures, before her condition subsequently plateaued. Low plasma uric acid, raised urinary xanthine and hypoxanthine, and positive urinary sulphite were found, which, coupled with assay of sulphite oxidase activity in cultured fibroblasts, confirmed the diagnosis. A sibling had isolated lens dislocation and an identical biochemical profile. MRI in both children was strikingly abnormal. Molybdenum cofactor deficiency may present as a late-onset variant with considerable phenotypic variability.

Age of Onset↗
PubMed1998

Inappropriate use of carbamazepine and vigabatrin in typical absence seizures.

Carbamazepine and vigabatrin are contraindicated in typical absence seizures. Of 18 consecutive referrals of children with resistant typical absences only, eight were erroneously treated with carbamazepine either as monotherapy or as an add-on. Vigabatrin was also used in the treatment of two children. Frequency of absences increased in four children treated with carbamazepine and two of these developed myoclonic jerks, which resolved on withdrawal of carbamazepine. Absences were aggravated in both cases where vigabatrin was added on to concurrent treatment. Optimal control of the absences was achieved with sodium valproate, lamotrigine, or ethosuximide alone or in combination.

Anticonvulsants↗
PubMed1998

Neuroimaging and spectroscopy in children with epileptic encephalopathies.

AIMS: To investigate the nature of the unifocal cortical abnormalities on FDG positron emission tomography (PET) in children with an epileptic encephalopathy but no focal abnormality on electroencephalogram or standard magnetic resonance imaging (MRI). METHODS: Repeat FDG PET, surface rendered high resolution MRI, and single voxel magnetic resonance proton spectroscopy of the areas of abnormal metabolism compared to the contralateral side in 11 children aged 2 to 12 years. Imaging was repeated after a median of 13 months. RESULTS: Visual analysis of repeat FDG PET revealed similar abnormalities in 10 of 11 children. Semiquantitative analysis revealed similar sited abnormalities in eight children. One child with ictal hypermetabolism initially had an inconsistent second scan. Magnetic resonance spectra in three children showed the N-acetyl-aspartate/choline ratio was lower in the hypometabolic focus than in the reciprocal area on the opposite side, in two children it was higher, and in one child it was equal. Surface rendered MRI was normal in seven of eight children, and showed temporal lobe asymmetry in one. CONCLUSION: In children with established epileptic encephalopathies most hypometabolic areas on FDG PET are stable over time. While focal neuronal loss is likely in these areas in some children, microdysplasias or other focal cortical dysplasias are probable in others.

Brain↗
PubMed1997

Salla disease--rare or underdiagnosed?

Salla disease is described in two English children. Eighty-seven of the 89 cases so far reported come from Finland. It may be genuinely rare outside Finland or possibly underdiagnosed. Although a lysosomal disorder, it lacks many of their more characteristic features. Deterioration, for example, in the paediatric age range is rare. The clinical features are, however, consistent and specific. Definitive diagnosis is achieved by demonstrating increased amounts of free sialic acid in cultured skin fibroblasts. If the colorimetric method in widespread use is employed for this, a false negative result may be obtained. High-pressure liquid chromatography is sufficiently sensitive. It is possible therefore that Salla disease is under-reported, both from lack of clinical awareness and from lack of appropriate laboratory confirmation.

Child↗
PubMed1997

Adaptive and maladaptive behaviour in children with epileptic encephalopathies: correlation with cerebral glucose metabolism.

In the childhood epileptic encephalopathies mental impairment is common and severe. Traditional cognitive assessment is difficult because of the low level of performance, autistic features, and the unpredictable effect of seizures. An alternative is to measure adaptive and maladaptive behaviour using instruments administered to the caregivers. Adults with different types of dementia have characteristic patterns of cortical glucose hypometabolism. Thirty-two children were studied using visual and semiquantitative analysis of 18fluorodeoxyglucose positron emission tomographic (PET) scans. The Vineland Scales and the Conners' Questionnaires were used to assess adaptive and maladaptive behaviour. The mean adaptive behaviour composite score was 37.3+/-15.6; all but one subject had a low adaptive level. A profile of relative strength in socialisation and weakness in daily living skills emerged. Up to two-thirds of children had abnormal behaviour patterns, particularly attention-deficit disorders and hyperactivity. Adaptive and maladaptive behaviour was not related to the presence or absence of focal cortical PET abnormalities. However, adaptive behaviour scores showed an inverse correlation with the degree of metabolic abnormality in the frontal lobes.

Adaptation, Psychological↗
PubMed1997

Early-onset benign occipital seizure susceptibility syndrome.

PURPOSE: Childhood epilepsy with occipital paroxysms (CEOP) is characterised by ictal visual hallucinations and occipital epileptiform activity on interictal EEG. A variant has been described with nonvisual symptoms including tonic head and eye deviation, vomiting, and episodes of partial status epilepticus. We fully documented the electroclinical features of such patients to determine whether classification separate from CEOP is justified. METHODS: This was a multicentre study with participating investigators submitting details of patients with idiopathic occipital seizures characterised by ictal head or eye deviation and vomiting. RESULTS: One hundred thirteen patients were recruited. Seizures began in early childhood (mean, 4.6 years) and occurred infrequently (mean total seizures, 3); 30% of patients had only a single seizure. Two thirds of seizures were nocturnal. Ictal eye deviation occurred in 79%, vomiting in 70%, and head deviation in 35%. Seizures were predominantly complex partial in type. Partial status epilepticus occurred in 44% of patients. Seventy-four percent of patients had occipital interictal EEG epileptiform activity, predominantly right sided, with fixation-off sensitivity. Extraoccipital EEG abnormalities occurred in 35% of patients. Prognosis was excellent: the mean duration of active seizures was 1 year. CONCLUSIONS: Although the two groups shared identical EEG features, the distinct clinical symptoms probably justify separate classification. Early-onset benign occipital seizure syndrome (EBOSS) is suggested as an appropriate name for the variant group.

Adolescent↗
PubMed1997

Cortical and subcortical glucose metabolism in childhood epileptic encephalopathies.

OBJECTIVES: Nearly one third of children with cryptogenic epileptic encephalopathies have been reported to have focal cortical defects on 18fluorodeoxyglucose (FDG) PET. As diffuse cortical dysfunction and involvement of subcortical structures, particularly the thalami, is postulated to underlie the propensity to seizures in these conditions, the aim was to determine the frequency of bilateral and diffuse cortical metabolic defects and of subcortical metabolic abnormalities in the same patients. METHODS: The interictal uptake of FDG was studied in 32 children with epileptic encephalopathies. Using a semiquantitative technique, the ratio of uptake in cortical regions and subcortical structures to that in the cerebellum was compared with that of age matched historical controls. Uptake more than 2 SD above ("hypermetabolic") or below ("hypometabolic") that of age matched controls was considered abnormal. RESULTS: Diffusely abnormal cortical up-take (nearly always hypometabolic) occurred in almost two thirds of patients; in all but two of the remaining patients at least one cortical region showed significantly decreased uptake bilaterally. When analysed as age cohorts, the mean cortical:cerebellar FDG uptake was significantly lower than that of controls in all cortical regions (P<0.005). Ninety per cent of patients had evidence of relative thalamic hypometabolism and in each age group there was a significant reduction in relative thalamic FDG uptake compared with that of controls (P<0.005). In nine out of 11 patients with unilateral cortical hypometabolic defects thalamic FDG up-take was lower ipsilateral to the cortical abnormality. CONCLUSIONS: Diffuse cortical dysfunction is common in the epileptic encephalopathies and may reflect the underlying cause of the condition or arise as a consequence of uncontrolled seizures. Altered thalamic glucose metabolism is further evidence of subcortical involvement in these conditions.

Cerebellum↗
PubMed1997

Visual and semiquantitative analysis of cortical FDG-PET scans in childhood epileptic encephalopathies.

UNLABELLED: The optimal method for analyzing PET scans in children being considered for epilepsy surgery is unresolved: Fully quantified methods are invasive, and the required controls are generally unavailable. We sought to compare visual inspection with semiquantitative analysis for the detection of cortical metabolic defects. METHODS: Thirty-two children with cryptogenic epileptic encephalopathies were studied prospectively with 18F-fluorodeoxyglucose (FDG) PET. Visual inspection was performed on separate occasions by independent observers. Four-millimeter circular regions of interest were used to sample radiotracer uptake in selected cortical regions. Asymmetry between homologous regions were calculated to detect focal abnormalities. Bilateral and diffuse abnormalities were assessed by comparing the ratio of cortical-to-cerebellar uptake in patients with historical age-matched controls. The sensitivity and specificity of visual inspection was compared with that of semiquantitative analysis for the detection of focal, bilateral and diffuse cortical metabolic abnormalities. RESULTS: Visual inspection revealed full inter-rater agreement for the presence of major focal abnormalities. The sensitivity and specificity for visual inspection compared to semiquantitative analysis were 77% and 92%, respectively, with semiquantitative analysis often revealing abnormalities to be more extensive than had been suspected visually. Compared with semiquantitative analysis, visual inspection had a low sensitivity but high specificity for the detection of bilateral and diffuse hypometabolism. CONCLUSION: Semiquantitative analysis gives clinically useful information additional to that obtained from visual inspection.

Brain↗
PubMed1996

Psychotic and severe behavioural reactions with vigabatrin: a review.

Behavioural disturbances and psychotic reactions are commoner in patients with epilepsy than in the general population and may be precipitated by the majority of antiepileptic drugs, including the newer ones. These reactions may be more frequent in patients with complex partial seizures, reflecting underlying temporal lobe pathology. A review of the literature on vigabatrin found an incidence of severe abnormal behaviour in controlled trials in adults of 3.4%. In children open studies gave an incidence of around 6%. This may be related to dosage and speed of introduction. Such reactions may be related to changes in seizure control, either unaccustomed good control (force normalisation) or breakdown in control, implying non-specific causative mechanisms. Alternatively, any relationship to control may be fortuitous and specific, unknown pharmacological mechanisms may be involved. Appropriate risk reduction measures include slow introduction, limiting the dose to that required for seizure control, slow withdrawal and increased vigilance in those on polytherapy or with psychiatric histories. Such advice is pertinent to all antiepileptic medications. Additionally, vigabatrin is probably contraindicated in idiopathic generalised epilepsies. Behavioural reactions are uncommon with vigabatrin, and have not been shown to be greater with it than with other antiepileptic agents. Therefore, it maybe inappropriate to withhold the drug from those who may benefit from it.

Adult↗
PubMed1996

Focal abnormalities detected by 18FDG PET in epileptic encephalopathies.

A prospective study of 32 children with epileptic encephalopathies 12 years or younger revealed a high incidence of focal cortical metabolic defects on 18-fluorodeoxyglucose positron emission tomography (PET) not suspected from clinical, EEG, or magnetic resonance imaging findings. PET scans were normal in all five children with typical de novo Lennox-Gastaut syndrome but showed cortical metabolic abnormalities in three out of four with atypical de novo Lennox-Gastaut syndrome, five out of six with Lennox-Gastaut syndrome following infantile spasms, six out of eight with severe myoclonic epilepsy in infancy, one out of two with epilepsy with myoclonic-astatic seizures, and four out of six with an unclassified epileptic encephalopathy. This suggests that some children with epileptic encephalopathies previously thought to have primary generalised seizures or seizures due to multifocal pathology may have unifocal cortical origin for their seizures. Such an origin may be amenable to surgery.

Child↗
PubMed1996

Difficulties in diagnosing intrinsic spinal cord tumours.

Thirteen children with intrinsic spinal cord tumours were seen between 1984 and 1995. In only one was this the presumptive diagnosis at referral, despite a high incidence of characteristic features. Eight had presented to their local paediatrician, four to local orthopaedic teams, and one to a general surgeon. Eleven had back pain. Eleven had either spinal curvature or change in gait. The interval between onset of symptoms and diagnosis ranged from one week to six years, with a mean of 17.5 months. In nine children symptoms had been present for four or more months. In nine, unrewarding investigations had been carried out. This paper highlights typical presenting features of these tumours and how earlier diagnosis can be achieved.

Back Pain↗