Joseph J. Melvin

Acute Disseminated Encephalomyelitis in Children: Discordant Neurologic and Neuroimaging Abnormalities and Response to Plasmapheresis

Objectives. To describe our experience with acute disseminated encephalomyelitis (ADEM), focusing on (1) the relationship between clinical course and MRI findings and (2) the response to plasmapheresis in a subgroup of patients. Methods. A retrospective record review was conducted of 13 children who were admitted as inpatients with the diagnosis of ADEM during the period 1998–2003. Results. Diagnosis was established by clinical signs and symptoms, cerebrospinal fluid changes and multifocal involvement of deep gray and white matter based on MRI. Initial therapy was high-dose methylprednisolone and intravenous immunoglobulin in 12 patients. One child improved spontaneously. Six of 12 children did not improve with corticosteroid treatment. All 6 had an acute progressive course neurologically, and 5 of them also showed a delay in the onset of neuroimaging changes, eventually developing lesions in the deep gray matter and brainstem. This latter group received 5 sessions of plasmapheresis and recovered over the course of several months with varying degrees of residual neurologic deficits. Conclusions. Presentation of ADEM with delayed development of MRI lesions in deep gray matter and brainstem may herald a prolonged clinical course and lack of response to glucocorticoid therapy. Plasmapheresis might be an effective therapeutic intervention in these patients. The role of plasmapheresis versus corticosteroids and intravenous immunoglobulin as a primary treatment of ADEM needs to be investigated further.

Intravenous Levetiracetam in Children With Epilepsy

Intravenous levetiracetam recently became available for use in patients aged >16 years. There are few data about its safety and efficacy in children. We retrospectively analyzed data from children treated with intravenous levetiracetam. Ten patients (6 female, 4 male), aged 3 weeks to 19 years, were treated with intravenous levetiracetam at a mean dose of 50.5 mg/kg/day for a mean duration of 4.9 days. Four patients received intravenous levetiracetam for acute repetitive seizures/status epilepticus, and three as replacement for oral levetiracetam because administration of oral levetiracetam was temporarily infeasible. One patient each received intravenous levetiracetam for seizure prophylaxis during brain biopsy, as maintenance treatment after acute seizures, and as substitute for sodium valproate. Three of four patients with acute repetitive seizures/status epilepticus became seizure-free; the fourth patient had a partial reduction in seizure frequency. All three patients who received intravenous levetiracetam as substitute for oral levetiracetam tolerated the switch well. The other three patients were seizure-free on intravenous levetiracetam. No serious adverse effects were observed, and all patients completed treatment with intravenous levetiracetam for the intended period. Intravenous levetiracetam may be effective in various clinical situations requiring intravenous administration of an antiepileptic drug.

Mitochondrial dysfunction in neuromuscular disorders.

This review deciphers aspects of mitochondrial (mt) dysfunction among nosologically, pathologically, and genetically diverse diseases of the skeletal muscle, lower motor neuron, and peripheral nerve, which fall outside the traditional realm of mt cytopathies. Special emphasis is given to well-characterized mt abnormalities in collagen VI myopathies (Ullrich congenital muscular dystrophy and Bethlem myopathy), megaconial congenital muscular dystrophy, limb-girdle muscular dystrophy type 2 (calpainopathy), centronuclear myopathies, core myopathies, inflammatory myopathies, spinal muscular atrophy, Charcot-Marie-Tooth neuropathy type 2, and drug-induced peripheral neuropathies. Among inflammatory myopathies, mt abnormalities are more prominent in inclusion body myositis and a subset of polymyositis with mt pathology, both of which are refractory to corticosteroid treatment. Awareness is raised about instances of phenotypic mimicry between cases harboring primary mtDNA depletion, in the context of mtDNA depletion syndrome, and established neuromuscular disorders such as spinal muscular atrophy. A substantial body of experimental work, derived from animal models, attests to a major role of mitochondria (mt) in the early process of muscle degeneration. Common mechanisms of mt-related cell injury include dysregulation of the mt permeability transition pore opening and defective autophagy. The therapeutic use of mt permeability transition pore modifiers holds promise in various neuromuscular disorders, including muscular dystrophies.

Presence of Oligoclonal T Cells in Cerebrospinal Fluid of a Child with Multiphasic Disseminated Encephalomyelitis following Hepatitis A Virus Infection

ABSTRACT We have investigated the clonality of β-chain T-cell receptor (TCR) transcripts from the cerebrospinal fluid (CSF) and peripheral blood from a 7-year old child who developed a multiphasic disseminated encephalomyelitis following an infection with hepatitis A virus. We amplified β-chain TCR transcripts by nonpalindromic adaptor (NPA)-PCR–Vβ-specific PCR. TCR transcripts from only five Vβ families (Vβ13, Vβ3, Vβ17, Vβ8, and Vβ20) were detected in CSF. The amplified products were combined, cloned, and sequenced. Sequence analysis revealed in the CSF substantial proportions of identical β-chain of TCR transcripts, demonstrating oligoclonal populations of T cells. Seventeen of 35 (48%) transcripts were 100% identical, demonstrating a major Vβ13.3 Dβ2.1 Jβ1.3 clonal expansion. Six of 35 (17%) transcripts were also 100% identical, revealing a second Vβ13 clonal expansion (Vβ13.1 Dβ2.1 Jβ1.2). Clonal expansions were also found within the Vβ3 family (transcript Vβ3.1 Dβ2.1 Jβ1.5 accounted for 5 of 35 transcripts [14%]) and within the Vβ20 family (transcript Vβ20.1 Dβ1.1 Jβ2.4 accounted for 3 of 35 transcripts [8%]). These results demonstrate the presence of T-cell oligoclonal expansions in the CSF of this patient following infection with hepatitis A virus. Analysis of the CDR3 motifs revealed that two of the clonally expanded T-cell clones exhibited substantial homology to myelin basic protein-reactive T-cell clones. In contrast, all Vβ TCR families were expressed in peripheral blood lymphocytes. Oligoclonal expansions of T cells were not detected in the peripheral blood of this patient. It remains to be determined whether these clonally expanded T cells are specific for hepatitis A viral antigen(s) or host central nervous system antigen(s) and whether molecular mimicry between hepatitis A viral protein and a host protein is responsible for demyelinating disease in this patient.

Aggravation of Seizures and/or EEG Features in Children Treated with Oxcarbazepine Monotherapy

Purpose: Exacerbation of epilepsy may occur following initiation of therapy with antiepileptic drugs (AEDs). The aim of this study is to analyze the clinical and EEG characteristics of a group of pediatric patients with worsening of seizures and/or EEG deterioration while on oxcarbazepine (OXC).

Efficacy and safety of lamotrigine monotherapy in children and adolescents with epilepsy.

Lamotrigine (LTG) has shown to confer broad-spectrum, well-tolerated control of epilepsy. Monotherapy is preferable over polytherapy because of better compliance, fewer adverse events, less interactions, lower teratogenicity and lower cost. The aim of this study is to evaluate the efficacy and safety of LTG monotherapy on seizure control in a cohort of children and adolescents with epilepsy. We retrospectively reviewed the records of children and adolescents treated with LTG monotherapy at our institution between 2001 and 2006. Data collected included demographics, seizure type, etiology of seizures, age at onset of seizures and at initiation of LTG treatment, number of antiepileptic drugs (AEDs) prior to LTG, dose of LTG, length of follow-up, treatment response, and adverse events. Seventy-two children and adolescents were identified (mean age 12.1 years); 37.5% had mental retardation. Age at onset of epilepsy was 5.7 years (0-16). Twenty three percent had symptomatic focal epilepsy, 15.5% idiopathic focal epilepsy, 19.4% symptomatic generalized epilepsy and 41.6% idiopathic generalized epilepsy. LTG was used as first-line monotherapy in 26.4% of patients and as a second-line monotherapy in 73.6%. Age at initiation of LTG therapy was 10 years (2.8-19). Mean number of AEDs tried prior to LTG was 1.3 (0-6). Mean dose of LTG was 5.5mg/kg/day (1.1-13.7). Mean follow-up period was 33 months (3 weeks to 11.5 years). The degree of seizure reduction was as follows: seizure free in 42%, 75-90% reduction in 17.4%, 50-74% in 11.6%, 25-49% in 10%. Sixteen percent had no change in seizure control and 3% became worse. The most common adverse event was rash (6.9%). Six (8.3%) patients discontinued LTG because of the adverse events. No patient had Stevens-Johnson syndrome. In conclusion, LTG was effective and well-tolerated as monotherapy in children and adolescents for both focal and generalized epilepsies.

Mitochondrial activity in pompe’s disease

Mitochondrial oxidative metabolism was examined in two infants with Pompes disease. The clinical diagnosis was confirmed by the demonstration of intralysosomal glycogen accumulation and a deficiency of acid alpha-D-glucosidase in muscle biopsies. Light and electron microscopy studies demonstrated a normal number of mitochondria with normal ultrastructure. Spectrophotometric measurements revealed that the specific activities of citrate synthase and the partial reactions of electron transport were markedly elevated in the skeletal muscle homogenates prepared from both infants with Pompes disease when calculated as micromoles per minute per gram wet weight of tissue. However, when respiratory chain enzyme activities were expressed relative to citrate synthase as a marker mitochondrial enzyme, a different pattern emerged, in which all Pompe muscle respiratory enzymes, except complex IV, were decreased relative to control subjects. These observations demonstrate that caution should be exercised when analyzing and interpreting data obtained from tissue homogenates in general and, in particular, in those prepared from tissues in which the wet weight of tissue may be altered, for example, by pathologic accumulation of carbohydrate or lipid.

Efficacy and Tolerability of Topiramate in Pediatric Migraine

About 5-10% of school-age children manifest migraine headaches. Treatment options for pediatric migraine are limited. Topiramate is approved for migraine prophylaxis in adults, but its use in children is limited. We retrospectively reviewed the records of 37 patients, i.e., 22 (60%) girls and 15 (40%) boys (mean age, 14 years; range, 7.3-20.5 years), diagnosed with migraine without aura in 30 (81%), with aura in four (11%), and abdominal, ophthalmoplegic, and catamenial in one each. The mean follow-up was 12 +/- 5 months standard deviation (S.D.). Clinical response was qualified as excellent, good, no change, or worse. Numbers of headaches per month were 15 +/- 7 S.D. prior to treatment and 3 +/- 3.4 S.D. (P < 0.001) after treatment. An excellent or good response (>50% migraine reduction) was attained in 28 patients (76%). Ten (27%) patients exhibited adverse effects. Patients taking >2 mg/kg/day were more likely to demonstrate side effects. The mean dose for patients without adverse effects was 1.27 +/- 0.7 mg/kg/day S.D. Those who reported adverse effects were taking a mean dose of 2.8 +/- 1.5 mg/kg/day S.D. This study demonstrated that topiramate is an effective, safe alternative for the prophylaxis of pediatric migraine. An acceptable risk/benefit maintenance dose was < or =2 mg/kg/day.

Infantile leukoencephalopathy owing to mitochondrial enzyme dysfunction.

Mitochondrial disease is classically associated with deep gray-matter lesions. When white matter is involved, the lesions are typically subcortical and overshadowed by more significant disease in the gray matter. We report six infants in five families who developed neurodegenerative diseases characterized primarily by abnormalities in deep white-matter structures such as the periventricular region, internal capsule, and corpus callosum. Five patients had impairments of mitochondrial enzymes, including a pre-electron transport chain defect and defects in respiratory chain complexes I, III, and IV (cytochrome-c oxidase). One patient, the sibling of one of the others, was diagnosed clinically with complex III deficiency. These six patients, along with others in the literature, appear to represent a distinct syndrome of mitochondrial infantile leukoencephalopathy. Our observations suggest that infants with leukoencephalopathies, especially leukodystrophies, who do not have one of the more common causes of white-matter disease should be evaluated for mitochondrial dysfunction. (J Child Neurol 2002;17:421-428).

Mitochondrial enzyme dysfunction in autism spectrum disorders; a novel biomarker revealed from buccal swab analysis

AIM Mitochondrial function studies in autism spectrum disorders (ASD) have detected skeletal muscle mitochondrial enzyme deficiencies in respiratory complex (RC) activities. As a muscle biopsy is expensive and invasive, we assessed RC-I and RC-IV activities in buccal swabs. METHODS 92 children with ASD and 68 controls were studied with immunocapture for RC-I and microspectrophotometry for RC-IV. RESULTS Significant RC activity deficiencies were found in 39 (42%) ASD patients (p < 0.01) and more prevalent in more severe cases. Aberrant RC overactivity was seen in 9 children. RC-I/RC-IV activity ratio was significantly increased in 64% of the entire ASD cohort including 76% of those more severely affected (p < 0.05). CONCLUSION Buccal swab analysis revealed extensive RC abnormalities in ASD providing a noninvasive biomarker to assess mitochondrial function in ASD patients.