H. Huntley Hardison

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.

Mitochondrial Dysfunction in Migraine

Migraine is the most frequent type of headache in children. In the 1980s, scientists first hypothesized a connection between migraine and mitochondrial (mt) disorders. More recent studies have suggested that at least some subtypes of migraine may be related to a mt defect. Different types of evidence support a relationship between mitochondria (mt) and migraine: (1) Biochemical evidence: Abnormal mt function translates into high intracellular penetration of Ca(2+), excessive production of free radicals, and deficient oxidative phosphorylation, which ultimately causes energy failure in neurons and astrocytes, thus triggering migraine mechanisms, including spreading depression. The mt markers of these events are low activity of superoxide dismutase, activation of cytochrome-c oxidase and nitric oxide, high levels of lactate and pyruvate, and low ratios of phosphocreatine-inorganic phosphate and N-acetylaspartate-choline. (2) Morphologic evidence: mt abnormalities have been shown in migraine sufferers, the most characteristic ones being direct observation in muscle biopsy of ragged red and cytochrome-c oxidase-negative fibers, accumulation of subsarcolemmal mt, and demonstration of giant mt with paracrystalline inclusions. (3) Genetic evidence: Recent studies have identified specific mutations responsible for migraine susceptibility. However, the investigation of the mtDNA mutations found in classic mt disorders (mt encephalomyopathy with lactic acidosis and stroke-like episodes, myoclonus epilepsy with ragged red fibers, Kearns-Sayre syndrome, and Leber hereditary optic neuropathy) has not demonstrated any association. Recently, 2 common mtDNA polymorphisms (16519C→T and 3010G→A) have been associated with pediatric cyclic vomiting syndrome and migraine. Also, POLG mutations (eg, p.T851 A, p.N468D, p.Y831C, p.G517V, and p.P163S) can cause disease through impaired replication of mtDNA, including migraine. Further studies to investigate the relationship between mtDNA and migraine will require very large sample sizes to obtain statistically significant results. (4) Therapeutic evidence: Several agents that have a positive effect on mt metabolism have shown to be effective in the treatment of migraines. The agents include riboflavin (B2), coenzyme Q10, magnesium, niacin, carnitine, topiramate, and lipoic acid. Further study is warranted to learn how mt interact with other factors to cause migraines. This will facilitate the development of new and more specific treatments that will reduce the frequency or severity or both of this disease.

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.

Sleep Study Abnormalities in Children With Attention Deficit Hyperactivity Disorder

The study objective was to describe polysomnographic findings in children with attention deficit hyperactivity disorder (ADHD) with diverse sleep problems. Polysomnographic data were retrospectively analyzed for 33 children (age 3-16 years) with ADHD who had sleep studies performed for diverse sleep complaints. Eight patients (24%) had obstructive sleep apnea, 10 (30%) had periodic limb movements of sleep, 8 (24%) had upper airway resistance syndrome, and 5 (15%) had obstructive hypoventilation. The ADHD group showed decreased sleep efficiency, increased arousal index, increased wake after sleep onset, decreased oxygen saturation nadir, and increased snoring, compared with control subjects. Compared with ADHD children without sleep disordered breathing, those who had sleep disordered breathing were significantly more obese and had more sleep architectural abnormalities (including increased sleep latency, increased rapid eye movement latency, increased wake after sleep onset, and increased arousal index with more oxygen desaturations), although total sleep time and sleep efficiency were not significantly different. Sleep disordered breathing and periodic limb movements of sleep appear to be common among children with ADHD who have symptoms of disturbed sleep.

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.

Efficacy and tolerability of topiramate in children younger than 2 years old

To evaluate the efficacy and tolerability of topiramate in children with epilepsy younger than 2 years of age, we retrospectively reviewed the records of patients treated at our institution between 2001 and 2003. Thirteen children ages 5 to 23 months, five boys and eight girls, were identified. Seizure types were partial (five), generalized tonic-clonic (three), myoclonic (one), and infantile spasms (four). The mean age at seizure onset was 9.7 months. Topiramate was started at a mean age of 11.4 months (4—23 months). The number of antiepileptic drugs prior to topiramate therapy ranged from zero to four. One patient had been on the ketogenic diet. Topiramate was used as monotherapy in seven children and as poly-therapy in six children. Mean follow-up was 14 months. The mean dose of topiramate was 8.8 mg/kg/day (2.5—18 mg/kg/day). The degree of seizure reduction was as follows: > 75% in five (38.5%) children, 50% to 75% in three (23%) children, and 0 to 25% in five (38.5%) children. Three of four (75%) patients with infantile spasms had a > 75% reduction in seizures. Adverse effects occurred in two children, including lethargy, hyperthermia, and anorexia. In children younger than 2 years of age, for whom the antiepileptic drug armamentarium is limited, topiramate appears to be an efficacious and safe therapeutic alternative for a variety of seizure types. (J Child Neurol 2005;20:667—670).

Efficacy of Lacosamide as Adjunctive Therapy in Children With Refractory Epilepsy

Lacosamide is a US Food and Drug Administration (FDA)–approved antiepileptic drug for patients 17 years or older with partial epilepsy. There are sparse data on children. The objective of our study was to evaluate its efficacy/safety in children with refractory epilepsy. Forty children (mean age 14.3 years) were treated with lacosamide at our institution (adjunctive therapy in 36, monotherapy in 4). Fifteen patients had symptomatic focal epilepsy, 2 had cryptogenic focal epilepsy, 20 had symptomatic generalized epilepsy, and 3 had cryptogenic generalized epilepsy. Two had juvenile myoclonic epilepsy and 5 had Lennox-Gastaut syndrome. Forty-two percent had at least >50% reduction in seizure frequency, and 6 became seizure free. Average dose was 7 mg/kg/d and average follow-up was 9.2 months. Responders had a 76.5% mean decrease in seizures. Fifteen children experienced an adverse reaction and 7 discontinued lacosamide (4: Ineffective, I: insurance denial, 1: tremor, 1: behavior). Lacosamide is effective and well-tolerated in children with refractory epilepsy.

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.

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.

Immunomodulatory Treatments in Epilepsy

The role of immunity and inflammation appears to be an integral part of the pathogenic processes associated with some seizures, particularly with refractory epilepsy. Prompt treatment with immunotherapy may lead to better outcomes. Immune treatment options for treatment of epilepsy include therapies such as corticosteroids, immunoglobulins, plasmapheresis, or steroid-sparing drugs such as azathioprine. Recent alternatives have included even more aggressive treatment with cyclophosphamide, anti-pre-B-lymphocyte monoclonal antibody rituximab, and monoclonal antibodies such as efalizumab or natalizumab, which are presently used for other inflammatory disorders. Randomized controlled trials of immunotherapy in presumed autoimmune epilepsy are needed to provide further support for the rapid use of immunotherapy in patients with immune mediated epilepsy.