Seizures, ataxia, developmental delay and the general paediatrician: glucose transporter 1 deficiency syndrome.

AIM: Glucose transporter 1 deficiency syndrome (GLUT1-DS) is an important condition for the general paediatrician's differential armamentarium. We describe a case series of eight patients in order to raise awareness of this treatable neurometabolic condition. The diagnosis of GLUT1-DS is suggested by a decreased absolute cerebrospinal fluid (CSF) glucose value (<2.2 mmol/L) or lowered CSF: plasma glucose ratio (<0.4). METHODS: This is a review of eight Queensland patients with GLUT1-DS. The clinical presentation, clinical course, laboratory investigations and treatment outcomes are discussed. RESULTS: The clinical features noted in our patient cohort include combinations of ataxia, developmental delay and a severe seizure disorder that is refractory to anticonvulsant medications. Seizures are the most common clinical manifestation and may be exacerbated by phenobarbitone. The paired CSF: plasma glucose results ranged from 0.2 to 0.39 (normal <0.6) with an average of 0.33. 3-O-Methyl-D-Glucose uptake and GLUT1 Genotyping analysis have been performed on five patients thus far. Rapid and impressive seizure control was observed in 100% of our patients once the ketogenic diet was instituted, with half of the cohort being able to wean completely from anticonvulsants. CONCLUSION: Children presenting with a clinical phenotype consisting of a refractory seizure disorder, ataxia and developmental delay should prompt the consideration of Glucose transporter 1 deficiency syndrome. While the diagnostic test of lumbar puncture is an invasive manoeuvre, the diagnosis provides a viable treatment option, the ketogenic diet. GLUT1-DS displays clinical heterogeneity, but the value of early diagnosis and treatment is demonstrated by our patient cohort.

Tolerability of topiramate in children and adolescents.

OBJECTIVE: To examine the tolerability of topiramate (TPM) in paediatric practice. METHODOLOGY: A retrospective cohort study of patients aged less than 18 years commenced on TPM by paediatric neurologists. Patients were identified from the dispensing databases of two paediatric tertiary referral hospitals and from the authority prescription records of four paediatric neurologists. The clinical data were obtained from the patients' medical records. RESULTS: There were 159 patients who were identified as having been commenced on TPM and follow-up data were available for 127 (80%) patients. The median (range) age at commencement of TPM was 8.1 (0.5-17.9) years, with 12 patients aged less than 2 years. After 4 years, 60% of patients had ceased the medication. Treatment limiting adverse effects included aggression/psychosis (n = 10), cognitive impairment/sedation (n = 6), anorexia/weight loss (n = 4) and desquamation (n = 1). Prior aggression (hazard ratio 5.91 (2.12-16.44)) and female gender (hazard ratio 2.94 (1.02-8.41)) were risk factors for ceasing TPM because of an adverse event. Thirty percent of children commenced on TPM experienced a treatment limiting adverse effect within 2 years of commencement. CONCLUSIONS: The frequency of treatment limiting adverse events in children receiving topiramate is higher than previously reported.

The effect of body size on the metabolic clearance of carbamazepine.

OBJECTIVES: To examine the profile of the known pathways of carbamazepine (CBZ) metabolism in a group of children and adolescents, and to test for associations with physical measurements, age and plasma hormonal levels. STUDY DESIGN: Cross-sectional study of children and adolescents attending a neurological outpatients department who were medicated with CBZ. Partial clearances of CBZ to CBZ-epoxide (CBZ-ep), CBZ-10,11-trans-diol (CBZ-diol), 2-hydroxy-CBZ (CBZ-2-OH), 3-hydroxy-CBZ (CBZ-3-OH), CBZ-acridan (CBZ-acr) and their respective glucuronides were calculated by relating 24-h recovery of these metabolites from urine to trough steady-state serum CBZ levels. CBZ and its metabolites were measured by a gradient high performance liquid chromatography (HPLC) method. Serum CBZ-ep, LH, FSH, prolactin, IGF-I, and testosterone or oestradiol and progesterone were also measured. Surface area (SA) and liver volume (LV) were calculated from height and weight. RESULTS: Twelve males and nine females with an age range of 6-17 years participated in the study. Partial clearance to each of the metabolites was most strongly correlated with the calculated size of the liver relative to body weight. These associations persisted when corrected for potential confounders using multiple regression analysis. CONCLUSION: In the age group studied, urinary clearance of CBZ to its known metabolites is proportional to the size of the liver relative to body weight.

Migrating partial seizures in infancy: two new cases.

Two infants presented at 3 weeks and 3 months of age with intractable partial seizures. Extensive investigations failed to identify an underlying cause. There was no response to antiepileptic drug therapy and no developmental progress following the onset of the seizures. In both infants there was a distinctive pattern of seizures that arose independently from multiple regions of both hemispheres. Interictal electroencephalograms revealed multifocal epileptiform activity. The infants died aged 9 and 12 months. One underwent postmortem examination, which was normal with no hippocampal sclerosis. These infants fulfill the diagnostic criteria of the syndrome of migrating partial seizures in infancy described by Coppola and colleagues in 1995.

Myoclonic encephalopathy of infancy: a 10 year review.

Myoclonic encephalopathy of infancy (MEI) is a unique cause of acute ataxia in infants and is a rare presentation of neuroblastoma. Five cases presenting to a tertiary referral children's hospital during a 10 year period are reviewed. Two cases were associated with a neuroblastoma. All children were treated with intramuscular injections of adrenocorticotropic hormone, with symptomatic improvement. One child died from an opportunistic infection following chemotherapy for neuroblastoma. The four survivors have mild to moderate clinical and intellectual deficits. Investigation and continuing observation for occult neural crest tumours is emphasized for all cases of MEI, though no underlying cause was found in 60% of children in this study.

Chronic diaphragmatic pacing in a quadriplegic boy.

Diaphragmatic pacing is a method of long-term artificial ventilation that is preferable to other forms of ventilation in suitable patients. Its use is described in a 14 year old quadriplegic boy who was previously hospital dependent and required continuous positive pressure ventilation.

Plasma vigabatrin enantiomer ratios in adults and children.

The new anticonvulsant vigabatrin (gamma-vinyl-gamma-aminobutyric acid) is normally supplied as a racemate, but its anticonvulsant effect is thought to reside in its [S]-enantiomer only. The plasma concentration ratio of the [R] to [S] enantiomers appears to remain constant across the vigabatrin dosage interval in adult volunteers, and in the present study this has also proved to be the case in 12 chronically treated adult epileptic patients. However, in 8 epileptic children chronically treated with other anticonvulsants and given add-on vigabatrin therapy because of failure to control seizures, plasma [R]:[S]-vigabatrin ratios changed across the drug dosage interval, the [R]-vigabatrin levels tending to be relatively higher soon after intake, and to fall more rapidly than the [S]-vigabatrin concentrations over the next few hours (mean half-lives 2.52 +/- SD 0.49 and 6.53 +/- SD 6.62 hours). The reason for the shorter half-life of [R]-vigabatrin in children remains to be elucidated, but it appears that measurement of racemic vigabatrin plasma concentrations in children, though not in adults, may lead to somewhat misleading conclusions as regards the amount of the circulating anticonvulsant [S]-vigabatrin.

Melioidosis with multiple cerebral abscesses.

Melioidosis from Pseudomonas pseudomallei is common in endemic areas (particularly southeast Asia) and is being recognized with increasing frequency in developed countries. Central nervous system involvement is a rare complication with a high mortality. A patient with multiple cerebral abscesses caused by this organism is presented to demonstrate that successful treatment is possible when a high index of clinical suspicion leads to early diagnosis.

Pleomorphic xanthoastrocytoma: report of two cases.

Two cases of pleomorphic xanthoastrocytoma are presented to draw attention to this relatively benign variant of glioma. The circumscribed tumors, each with a cystic component, were located superficially, one in the mesial right temporal lobe and one in the right temporoparietal region. The patients were aged 12 and 14 years, and it is now almost 7 years since the onset of symptoms in the 12-year-old boy. The optimal plan of management is discussed.

Some specific neurological complications of acute lymphocyte leukaemia of childhood.

Aggressive chemotherapy and prophylactic central nervous system irradiation have increased the survival time of children with acute lymphatic leukaemia. As a result of treatment complex neurological problems are appearing. Computerized axial tomography allows more definite elucidation of these problems. 7 of 11 treated patients studied by this technique showed the presence of intracranial calcification and patchy cerebral atrophy, raising the questions of the quality of survival and the relationship of the findings to the cytotoxic drugs used.

Tay Sachs disease in a child and management of a subsequent pregnancy.

A case is reported illustrating the typical features of Tay-Sachs disease, the light microscopy and ultrastructure of the stored material in the condition, and the feasibility of prenatal diagnosis of the disorder.