Intravenous paraldehyde for seizure control in newborn infants

DNA–Protein Cross-link Formation in Burkitt Lymphoma Cells Cultured with Benzaldehyde and the Sedative Paraldehyde

Exposure to aldehydes represents potential risks to human and animal health. Cyclic aldehydes such as benzaldehyde, 2-furaldehyde, and paraldehyde were found to induce formation of stable DNA-protein cross-links (DPXs) in cultured human lymphoma cells. A relationship between increased cytotoxicity and DPX formation was observed with each aldehyde. Paraldehyde is a sedative drug used predominately in treatment of ethanol withdrawal. Paraldehyde was the most potent cross-linking aldehyde studied, yet least cytotoxic. Although DPX formation by aliphatic aldehydes is well-known, this study confirms the potential for cyclic aldehydes to cause formation of DPXs in cultured cells at therapeutically relevant doses.

Drug treatment of neonatal seizures by neonatologists and paediatric neurologists

OBJECTIVE

To survey anti-epileptic drug (AED) treatment of early-onset neonatal seizures by neonatologists and paediatric neurologists.

METHODS

A self-administered questionnaire was posted to Australian and New Zealand neonatologists and paediatric neurologists. Participants were given the hypothetical case of a full-term infant with early-onset seizures following perinatal asphyxia and asked to nominate their preferred AED for treatment of three seizure episodes during the first 24 h.

RESULTS

One hundred and seven (57%) of 187 individuals answered the questionnaire: neonatologists responded more often than neurologists (chi(2) (1,187) = 7.18, P = 0.007). Phenobarbitone was used by 95% of the respondents to treat the first episode of seizures and 75% of them used an appropriate loading dose (20 mg/kg). Phenobarbitone was used by 84 and 40% of the respondents to treat the second- and third-seizure episodes, respectively. Neonatologists used phenobarbitone, phenytoin and a benzodiazepine with equal frequency to treat a third episode of seizures, whereas neurologists rarely used a benzodiazepine. Neonatologists used significantly larger total doses of phenobarbitone than neurologists. Very few respondents used pyridoxine to treat recurrent seizures that were historically linked to perinatal asphyxia and hypoxic-ischaemic encephalopathy. Neonatologists were more likely than neurologists to discontinue AED within a few days of seizure cessation (chi(2) (1,106) = 11.60, P = 0.0006).

CONCLUSIONS

Australian and New Zealand neonatologists and paediatric neurologists generally use phenobarbitone to treat neonatal seizures presumed to be owing to hypoxic-ischaemic encephalopathy, though they do not always use appropriate doses. Neonatologists use phenobarbitone, phenytoin or a benzodiazepine for second and third episodes of seizures, whereas neurologists tend not to use benzodiazepines. Neonatologists use larger total doses of phenobarbitone than neurologists in pursuit of seizure control. Neonatologists discontinue AED earlier than neurologists.

Determination of paraldehyde by gas chromatography in whole blood from children

A rapid, sensitive and selective gas chromatographic method with flame ionization detection was developed for the determination of paraldehyde in small blood samples taken from children. Whole blood samples (300 microl) collected in a 3 ml Wheaton glass sample vial were spiked with acetone (internal standard: 15 ng) followed by addition of concentrated hydrochloric acid. The mixture was heated in the sealed airtight sample vial in a water bath (96 Celsius; 5 min) to depolymerize paraldehyde to acetaldehyde. A 2 ml aliquot of the headspace was analyzed by gas chromatography with flame ionization detector using a stainless steel column (3 m x 4 mm i.d.) packed with 10% Carbowax 20 M/ 2% KOH on 80/100 Chromosorb WAW. Calibration curves were linear from 1.0-20 microg (r2>0.99). The limit of detection was 1.5 microg/ml, while relative mean recoveries at 2 and 18 microg were 105.6 +/- 8.4 and 101.2 +/- 5.9%, respectively (n = 10 for each level). Intra- and inter-assay relative standard deviations at 2, 10 and 18 microg were <15%. There was no interference from other drugs concurrently used in children with severe malaria, such as anticonvulsants (diazepam, phenytoin, phenobarbitone), antipyretics/analgesics (paracetamol and salicylate), antibiotics (gentamicin, chloramphenicol, benzyl penicillin) and antimalarials (chloroquine, quinine, proguanil, cycloguanil, pyrimethamine and sulfadoxine). The method was successfully applied for pharmacokinetic studies of paraldehyde in children with convulsions associated with severe malaria.

Pervasive seizures caused by hypoxic-ischemic encephalopathy: treatment with intravenous paraldehyde

Seizures are commonly associated with hypoxic-ischemic encephalopathy. Although the majority of cases are controlled with first- or second-line therapy, others develop pervasive seizures, requiring multiple anticonvulsants. To provide data on the incidence of seizures and response to anticonvulsant therapies, a cohort of 90 term infants with hypoxic-ischemic encephalopathy treated at our institution between January 1, 1995, and July 1, 1999, was reviewed. Of the 60 infants who developed seizures, 59 received phenobarbital initially; in 29 cases, the seizures resolved. The remaining 30 infants received phenytoin as a second-line anticonvulsant, and seizures stopped in 10 cases. The 20 infants with ongoing pervasive seizures were treated with intravenous paraldehyde.

Neonatal seizures and neonatal epileptic syndromes

The neonatal period is defined as the first 28 days of life of a term infant; for premature infants the limit of this period is 44 completed weeks of the infant's conceptional age (CA)-defined as the chronological age plus gestational age (GA) at birth. The clinical and electroencephalographic (EEG) manifestations of seizures during this period are determined primarily by the development features of the immature brain at the time of seizure onset, but are also related to the type and diversity of etiologies and risk-factors for seizures neonates may face early in life. Neonatal seizures may be strikingly different from the clinical and electrical seizures of older children and adults. In addition, findings from basic science investigations suggest that immature animals are more likely to experience seizures in response to injury than more mature animals, although the developing brain is less susceptible to seizure-induced injury.

Efficacy of lamotrigine in refractory neonatal seizures

A newborn infant with seizures of unknown etiology that were refractory to treatment with phenobarbitone, phenytoin, midazolam, clonazepam, and vigabatrin is reported. The introduction of the new antiepileptic drug lamotrigine was followed by rapid and sustained control of the seizures.

Multiple sclerosis: multiple etiologies, multiple genes?

Multiple sclerosis is a chronic inflammatory disease characterized by multifocal damage of the central nervous system myelin. Both humoral and cell-mediated immune abnormalities have been observed in patients with multiple sclerosis, but their relation to the demyelination process is not understood. The etiology of the disease is still unknown; however, evidence exists for an interplay between environmental and genetic factors. Several genes are involved in determining the disease susceptibility, at least one of them encoded within human leukocyte antigen gene complex. Other genomic regions coding for components of the immune system or myelin have also been suggested. Clinical, immunological and genetic data suggest that multiple sclerosis may turn out to be a heterogeneous disease. Therefore, molecular genetic dissection of this complex disease should provide important clues to its pathogenesis as well as unravel metabolic pathways for potential therapeutic or preventive strategies. This review will give an overview of recent progress and future challenges in identifying susceptibility genes for multiple sclerosis.

Epidemiologic evidence for multiple sclerosis as an infection

The worldwide distribution of multiple sclerosis (MS) can be described within three zones of frequency: high, medium, and low. The disease has a predilection for white races and for women. Migration studies show that changing residence changes MS risk. Studies of persons moving from high- to low-risk areas indicate that in the high-risk areas, MS is acquired by about age 15. Moves from low- to high-risk areas suggest that susceptibility is limited to persons between about ages 11 and 45. MS on the Faroe Islands has occurred as four successive epidemics beginning in 1943. The disease appears to have been introduced by British troops who occupied the islands for 5 years from 1940, and it has remained geographically localized within the Faroes for half a century. What was introduced must have been an infection, called the primary MS affection (PMSA), that was spread to and from successive cohorts of Faroese. In this concept, PMSA is a single widespread systemic infectious disease (perhaps asymptomatic) that only seldom leads to clinical neurologic MS. PMSA is also characterized by a need for prolonged exposure, limited age of susceptibility, and prolonged incubation. I believe that clinical MS is the rare late outcome of a specific, but unknown, infectious disease of adolescence and young adulthood and that this infection could well be caused by a thus-far-unidentified (retro)virus.

Epidemiology of multiple sclerosis in U.S. veterans: V. Ancestry and the risk of multiple sclerosis

Self-reported ancestry data for the U.S. population from the 1980 decennial census and multiple sclerosis (MS) risk data derived from a large series of World War II white male veterans with MS and matched controls were aggregated on a state level and analyzed to determine the relationship between ancestry and MS risk. A significant portion of the state-by-state variation in MS risk is explainable statistically by differences in ancestry among state populations, even when geographic latitude is included in analyses. In the main, Swedish and other Scandinavian ancestry is most consistently associated with places with increased MS risk. In some analyses, Italian, French, and (to a lesser extent) Scottish ancestries are also associated with increased risk, whereas English and Dutch ancestries are each associated with decreased risk, but most of these non-Scandinavian correlations may reflect predominantly geography per se. These findings provide evidence that ancestry of the resident population, a confounded measure of genetic susceptibility and cultural environment, is part of the complicated picture of MS as a disease of place.

Neonatal seizures: diagnosis and treatment

Neonatal seizures are a frequent problem encountered in neonatal nurseries, but their significance is controversial. Some investigators regard newborn seizures as simply epiphenomena and reflective of brain injury, whereas others note associated metabolic and physiologic aberrations suggesting that seizures per se are injurious to the central nervous system. The proper approach to the treatment of neonatal seizures depends on the etiology because treatment differs if seizures are of metabolic, toxic, or structural origin. Most studies reporting the efficacy of anticonvulsant agents neither define the seizure characteristics being treated nor use electroencephalographic documentation of seizure activity. The choice of anticonvulsants has been based on tradition rather than on the proven superiority of one agent over another. Although several anticonvulsants are available, phenobarbital remains the drug most frequently chosen as the initial agent in treatment. The important pharmacologic considerations of anticonvulsants include route of administration, ability to achieve therapeutically efficacious and predictable plasma levels rapidly, drug distribution, the availability and affinity of receptor sites, protein-binding characteristics, effects on brain growth, and cardiovascular toxicities. At the present time, critical questions remain regarding the effects of both seizures and anticonvulsants on the developing central nervous system.

Multiple sclerosis in Australia and New Zealand: are the determinants genetic or environmental?

The prevalence of multiple sclerosis (MS) has been recently reported from nine regions of Australia and New Zealand. There is a marked variation of prevalence with latitude. MS is seven times more common in southern New Zealand than in tropical Queensland. On current evidence, it is suggested that in both countries this variation is predominantly due to environmental rather than genetic factors.

The effect of paraldehyde on intravenous tubing sets

Paraldehyde is used in the treatment of status epilepticus, alcohol withdrawal, and delirium tremens. Because it is a solvent, concerns have been raised about infusing it through plastic intravenous tubing sets. In a three-phase study, 4% paraldehyde in 5% dextrose solution was analyzed over 24 hours for photodegradation, adsorption to polyvinylchloride- (PVC) and polyethylene- (PE) lined intravenous tubing, and the presence of di(2-ethylhexyl) phthalate (DEHP). Paraldehyde and DEHP samples were quantified by gas chromatography, and DEHP was confirmed by mass spectral analysis. On exposure to light for 24 hours, the concentration of paraldehyde decreased from 100 to 97%. This decrease is statistically significant but clinically insignificant. A 24-hour continuous infusion of paraldehyde through the two types of tubing revealed a decrease in concentration attributable to adsorption of 4% with PE and 13% with PVC tubing at 2 hours. In addition, there was no appreciable leaching of DEHP over 24 hours with either type of tubing. Concerns about paraldehyde's light instability and effects on tubing integrity appear to be unwarranted with commercially available intravenous administration sets.

Recent advances in the diagnosis, treatment, and prognosis of neonatal seizures

Current knowledge about the diagnosis, treatment, and prognosis of neonatal seizures is reviewed. The pitfalls in establishing the diagnosis are emphasized and the usefulness of new electrodiagnostic techniques is discussed. A protocol for treating neonatal seizures is suggested. Finally, the clinical and electroencephalographic variables which are relevant in determining neurologic outcome are discussed.

Lidocaine for treatment of severe seizures in newborn infants. I. Clinical effects and cerebral electrical activity monitoring

The anticonvulsive effect of lidocaine was evaluated in 46 newborn infants with severe, recurrent seizures. Before the lidocaine all infants were being given phenobarbital, and 22 infants were also treated with diazepam. Different dosages of lidocaine were tested. A loading dose of 2 mg/kg followed by i.v. infusion of 6 mg/kg/hour was the most effective dosage and had an immediate anticonvulsive effect in 18 of 25 infants; within 30 min the same effect was attained in another five of the infants, with an overall seizure control in 92% of the sample population. During the lidocaine treatment cerebral electrical activity was followed continuously with a cerebral function monitor (CFM), which also enabled evaluation of the treatment. No serious side effects on blood-pressure, heart-rate or cerebral electrical activity were registered. For newborn infants with severe recurrent seizures not responding to other drugs, lidocaine is an effective additional mode of treatment.

Neonatal seizures: a commentary on selected aspects

Despite the immaturity of the newborn brain, the neonatal period is reported to have a very high frequency of seizures. This review concludes that many of the neonatal events that are called seizures probably originate from subcortical structures, have little in common with cortical seizures seen in older individuals, and may not benefit from conventional anticonvulsant treatment. Many studies of anticonvulsants in the newborn have important methodologic problems, compounded by the fact that the seizures tend to spontaneously remit with the resolution of the acute hypoxic-ischemic encephalopathy that is most often the cause. Randomized trials of anticonvulsants in this setting have not been carried out. Even in many of these seizures do not originate in the cortex, they still imply profound cortical disturbance and are associated with high mortality and morbidity. It is unknown if the type and duration of treatment influence the long-term, overall outcome. The seizures usually stop in the newborn period, and anticonvulsants beyond hospital discharge seem unwarranted because they are unlikely to prevent subsequent epilepsy. Newer investigations, including video-EEG and nuclear magnetic resonance studies, may clarify the real significance of neonatal seizures.