Continuous, generalized, high-voltage fast activity and FIRDA in two children

Generalized and Lateralized Rhythmic Patterns

The relationship between generalized and lateralized rhythmic delta activity (RDA) and seizures is more ambiguous than the relationship between periodic discharges and seizures. Although frontally predominant generalized RDA is not associated with seizures, occipitally predominant RDA may be associated with the absence of seizures. Lateralized RDA seems to be more strongly associated with the presence of seizure activity. Appropriate recognition of generalized RDA and lateralized rhythmic delta activity may be confounded by benign etiologies of RDA, such as phi rhythm, slow alpha variant, subclinical rhythmic electrographic discharges of adults, or hyperventilation-induced high-amplitude rhythmic slowing. Angelman syndrome and NMDA-receptor antibody encephalitis can also produce morphologically distinct patterns of RDA.

Epilepsy in children with Menkes disease: a systematic review of literature

Menkes disease is a lethal multisystemic disorder of copper metabolism characterized by connective tissue abnormalities, progressive neurodegeneration and peculiar "kinky hair." Epilepsy is one of the main clinical features of this disease but it has been described in detail by only a few authors. Most patients develop seizures from 2 to 3 months of age, accompanied by a neurodevelopmental regression. The history of epilepsy is usually characterized by 3 stages: an early stage with focal clonic seizures and status epilepticus, an intermediate stage with infantile spasms, and a late stage with multifocal, myoclonic, and tonic seizures. At the onset, epilepsy can be controlled with anticonvulsant therapy, whereas with the progression of disease, it becomes extremely resistant to all antiepileptic drugs. In this article, we analyze clinical and electroencephalographic (EEG) characteristics of epilepsy in patients with this syndrome.

Frontal intermittent rhythmic delta activity (FIRDA): is there a clinical significance in children and adolescents?

BACKGROUND

Frontal intermittent rhythmic delta activity (FIRDA) has been studied extensively in adults but published literature about its clinical correlates in children and adolescents is comparatively limited.

AIMS

This study was performed to find more evidence regarding the clinical significance of this electrographic pattern in the pediatric population.

METHODS

All electroencephalograms (EEGs) with FIRDA between 07/01/2006 and 12/31/2009 at our institution were identified. Clinical data were collected from charts of patients with FIRDA. A comparison group consisting of patients matched for age and location was assembled.

RESULTS

We identified 26 EEGs in 22 patients with this electrographic pattern from a total of 4627 EEGs. All 26 EEGs were performed because of a history of seizures or to rule out seizures. Two of the 22 patients did not have evaluable clinical data. Of the remaining, 18 had seizures. The events in 2 patients were determined to be non epileptic. Amongst the 18 patients with seizures, 10 had associated epileptiform discharges and only 2 were without epileptiform activity or localizing or lateralizing features. Two patients had brain tumor. Six patients had hydrocephalus. Three patients had encephalopathy due to anoxic, metabolic or infectious etiology. There was no statistically significant difference between the study and the comparison group for occurrence of brain tumor, hydrocephalus or encephalopathy.

CONCLUSIONS

FIRDA was uncommonly observed. It was associated with a variety of conditions and was not a specific marker of brain tumor, hydrocephalus or encephalopathy.

The significance of frontal intermittent rhythmic delta activity in children

OBJECTIVE

To determine the correlation between frontal intermittent rhythmic delta activity (FIRDA) and the clinical and radiological correlates in children.

METHODS

Retrospective review of the EEG and imaging studies of 37 children with documented FIRDA.

RESULTS

FIRDA was associated with multiple neurological conditions and not necessarily with midline lesions. Patients with abnormal neurological exam had a longer FIRDA duration (average 9.5 seconds) compared to children with no reported abnormal examination (average of 6.5 seconds). FIRDA ranged from 2 to 2.5 Hz (n = 15), 3 Hz (n = 17) and from 1.5 to 3 Hz (n = 5) and there was a significant association between the duration of FIRDA and abnormal laboratory tests (p. < 0.05, Student's T test).

CONCLUSION

FIRDA was not correlated with midline brain lesions in children. FIRDA may be a non specific oscillation of an unhealthy pediatric brain with or without seizures.

Clinical correlates of frontal intermittent rhythmic delta activity in children

Frontal intermittent rhythmic delta activity is an electrographic pattern of unclear origin. Previously thought to correlate with deep midline and infratentorial pathology, rather, it appears to be associated with encephalopathy states in adults. The significance of frontal intermittent rhythmic delta activity in children has not been studied. We analyzed the electrographic characteristics and clinical associations of pediatric frontal intermittent rhythmic delta activity. This pattern was rarely detected, occurring in 20 of 1500 electroencephalographic (EEG) studies. Patients' ages ranged between 1.5 and 17 years. Most patients were awake and showed no signs of acute encephalopathy when frontal intermittent rhythmic delta activity occurred. Half of the children were cognitively impaired, and half had a history of epilepsy. Epileptiform activity was present in 55% of the EEG recordings. However, frontal intermittent rhythmic delta activity was part of the epileptiform discharge in only a minority of cases. The duration of frontal intermittent rhythmic delta activity bursts was longer in the mentally retarded group. Most patients did not have structural brain pathology. None had deep midline or infratentorial lesions. In conclusion, frontal intermittent rhythmic delta activity is rare in children, is not associated with acute encephalopathy or with deep midline or infratentorial lesions, and tends to occur during wakefulness. The electrographic characteristics of frontal intermittent rhythmic delta activity appear to differ between cognitively normal and mentally retarded children.

Clinical and radiologic correlates of frontal intermittent rhythmic delta activity

To assess the clinical and radiologic correlates of frontal intermittent rhythmic delta activity (FIRDA), the authors reviewed the hospital charts of patients whose EEGs depicted this EEG finding, and recorded their past medical and neurologic history, the reason for hospital admission, and their neurologic status both on admission and during EEG recordings. Laboratory results on admission and concomitant to the EEG recording, computed tomography, or MRI findings during hospital admission were also reviewed. Sixty-eight patients were assessed. The gender ratio was 1:1; mean age was 56 years. Chronic disease occurred in 78% of patients, including hypertension (34%), diabetes (32%), and renal failure (18%). On admission, renal failure (n = 34) and hyperglycemia (n = 22) were most prominent. The majority of patients had at least one abnormal laboratory result. Thirty-eight of 51 patients in whom the level of consciousness was stated during EEG were described as awake. More than half of 58 patients whose EEG background activity was stipulated demonstrated diffuse slowing, mostly in the theta range. MRI was abnormal in 15 of 17 patients. Intrahemispheric lesions, particularly ischemic and hemorrhagic, were most common (n = 10), followed by basal ganglia lacunae (n = 4). Computed tomography was abnormal in 29 of 44 patients. Hemispheric pathology, diffuse or localized, occurred in 22 patients. Frontal intermittent rhythmic delta activity is associated with mild to moderate encephalopathy and is detected principally in awake patients. Most patients in this series had chronic systemic illness. Old ischemic structural brain lesions may predispose some patients to develop FIRDA during acute metabolic derangement, such as uremia and hyperglycemia. Frontal intermittent rhythmic delta activity was not associated with EEG epileptiform activity. Deep midline lesions, posterior fossa tumors, and hydrocephalus were not detected in this series of patients with FIRDA.

Central nervous system involvement in gyrate atrophy of the choroid and retina with hyperornithinaemia

In gyrate atrophy of the choroid and retina with hyperornithinaemia (GA), a genetically determined deficiency of ornithine delta-aminotransferase activity leads to high ornithine concentrations in body fluids. GA is characterized by centripetally progressing retinal and choroidal destruction and selective atrophy with tubular aggregates in type II skeletal muscle fibres. These findings have been suggested to be mediated by hyperornithinaemia-induced deficiency of high-energy creatine phosphate. As abnormal brain magnetic resonance images and electroencephalograms are found in another disorder of creatine metabolism, guanidinoacetate methyltransferase deficiency, we investigated the central nervous system involvement in GA, which seems to be associated with a milder degree of phosphocreatine deficiency. We compared 23 untreated GA patients with age-matched healthy controls, and with 9 patients who had received creatine or creatine precursor supplementation daily for several years. The mean age of the patients (32 +/- 18 years) was similar to that of the controls (36 +/- 22 years). The MRI or EEG findings of the patients on creatine supplementation did not differ from those of the untreated group. Brain MRI revealed degenerative lesions in the white matter in 50% of the GA patients, and 70% of the patients had premature atrophic changes, with a striking increase in the number of Virchow's spaces. Of the patients whose EEG was recorded, 58% had abnormal slow background activity, focal lesions or high-amplitude beta rhythm (> 50 microV). The EEG findings were not associated with the MRI changes or with the age or the sex of the patients. Early degenerative and atrophic brain changes and abnormal EEG are thus features of GA, in addition to the well-characterized eye and muscle manifestations.

Frontal intermittent rhythmic delta activity (FIRDA) in pituitary adenoma

We report a case of FIRDA in the EEG of a patient diagnosed as major depression with pituitary adenoma and hyponatremic encephalopathy. The pituitary adenoma appeared to be a major factor responsible for FIRDA in this case. Although other factors associated with this case, i.e., diffuse encephalopathy and administration of antipsychotic drugs, have been reported to be causative, FIRDA remained in the EEG after these other factors diminished. Although size of the pituitary adenoma that might be associated with FIRDA in the EEG recording was not identified in this study, FIRDA may be associated with a small pituitary adenoma less than 10 mm in diameter. We think a diligent search for additional pathology is recommended if FIRDA is seen in the EEG of an otherwise normal patient.