Common causes of uncommon seizures

Pediatric Metronidazole-Induced Encephalopathy: A Case Report and Review of the Literature

Metronidazole-induced encephalopathy is a rare toxic encephalopathy secondary to the common use to this antimicrobial drug. It has been reported mainly in adult patients but only rarely in children. Owing to possible devastating complication of this disease, clinicians should have a higher index of suspicion for encephalopathic patients on metronidazole therapy. Here, we report a 5-month-old infant with metronidazole-induced encephalopathy presenting with nonconvulsive status epilepticus. A review of the literature in pediatric, as well as adult metronidazole-induced encephalopathy, is also provided.

Metronidazole Encephalopathy EEG Features: A Case Report with Systematic Review of the Literature

Metronidazole-induced encephalopathy (MIE) is a rare and often under-recognized iatrogenic condition. The diagnosis should be considered in metronidazole-treated patients presenting with acute encephalopathy, unprovoked seizures and cerebellar signs. While typical magnetic resonance imaging (MRI) findings strongly support the diagnosis, electroencephalography (EEG) features have been rarely reported and poorly described. We present a longitudinal EEG assessment in one patient with encephalopathy due to metronidazole toxicity who presented a peculiar EEG pattern presentation and evolution. During the acute phase of encephalopathy, the EEG showed a monomorphic, sharply contoured theta activity symmetrically represented over frontal regions with an anterior-posterior progression which evolved in parallel with clinical worsening. Together with a systematic review of the literature, we discuss whether this EEG activity may represent a distinct neurophysiological correlate of 'cerebellar encephalopathy'.

Pharmacological potential of methylxanthines: Retrospective analysis and future expectations

Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.

Theophylline potentiates lipopolysaccharide-induced NO production in cultured astrocytes

Elucidation of the functions of astrocytes is important for understanding of the pathogenic mechanism of various neurodegenerative diseases. Theophylline is a common drug for bronchial asthma and occasionally develops side-effects, such as acute encephalopathy; although the pathogenic mechanism of the side-effects is unknown. The lipopolysaccharide (LPS)-induced nitricoxide (NO) production is generally used for an index of the activation of astrocyte in vitro. In this study, in order to elucidate the effect of theophylline on the astrocytic functions, we examined the LPS-induced NO production and the expression of iNOS in cultured rat cortex astrocytes.Theophylline alone could not induce the NO production; however, NO production induced by LPS was enhanced by theophylline in a dose-dependent manner; and by isobutylmethylxanthine, a phosphodiesterase inhibitor. The theophylline enhancement of LPS-induced NO production was further increased by dibutyryl cyclic AMP, a membrane-permeable cAMP analog; and by forskolin, an adenylate cyclase activator. When the cells were preincubated with Rp-8-Br-cAMP, an inhibitor of protein kinase A, the theophylline enhancement of LPS-induced NO production was decreased. The extent of iNOS protein expression induced by LPS was also enhanced by theophylline.It is likely that phosphodiesterase inhibition is a major action mechanism for the theophylline enhancement of LPS-induced NO production in astrocytes. Theophylline-induced acute encephalopathy might be due to the hyper-activation of astrocytes via cAMP signaling to produce excess amount of NO.

Nonconvulsive status with metronidazole

OBJECTIVE

To expand the adverse events associated with metronidazole to include nonconvulsive status epilepticus (NCSE).

DESIGN

Observational single case report of a rare association.

SETTING

Hospitalized lung transplant recipient treated with metronidazole for prevention of infection.

PATIENT

A 56-year-old man with systemic symptoms, peripheral neuropathy, generalized seizure, and a subsequent acute deterioration of mental status due to NCSE.

INTERVENTIONS

Administration of midazolam was successful in terminating status epilepticus.

MAIN OUTCOME MEASURES

Abrupt termination of NCSE was evident on continuous bedside electroencephalogam associated with clinical resolution of mental status.

RESULTS

Recovery occurred from NCSE eventually deteriorating to a fatal outcome.

CONCLUSIONS

Metronidazole may be associated with successfully treated NCSE.

Acute symptomatic seizures and systemic illness

PURPOSE OF REVIEW

This article addresses the occurrence of acute symptomatic seizures in the setting of many medical illnesses.

RECENT FINDINGS

Many medical illnesses can cause seizures. Metabolic derangements, such as disorders of serum glucose metabolism, cause seizures, as well as other neurologic manifestations. Many medicines (such as antibiotics, antivirals, antidepressants, and antipsychotics), whether used at typical doses or in overdosage, can lead to acute symptomatic seizures.

SUMMARY

Acute symptomatic seizures occur most often in illnesses that directly injure the brain. Trauma, stroke, CNS tumors, and CNS infection very commonly cause seizures. However, many medical illnesses do not directly injure the brain but lead to neurologic signs and symptoms, such as seizures. Recognizing these effects, especially in critically ill patients, is important for optimizing medical care.

Neurologic complications and outcomes of pandemic (H1N1) 2009 in Korean children

Neurologic complications of children with influenza A H1N1 2009 pandemic, diagnosed in two consecutive influenza seasons were retrospectively reviewed to seek better outcomes in future outbreaks. Patient demographics, clinical manifestations and neurologic outcomes were reviewed. A total of 1,389 children were diagnosed with influenza A H1N1 by real-time reverse transcriptase-polymerase chain reaction. Of these, 23 (1.7%) patients had neurologic involvement. Their mean age was 5.9 ± 3.6 yr (range, 6 months to 11 yr) and 16 (69.9%) were boys. None of the 23 patients had been vaccinated for influenza A H1N1 and seasonal influenzas. Twenty-two of the 23 patients presented with seizures. Clinical features included febrile convulsion (n = 19), afebrile convulsion (n = 1), aseptic meningitis (n = 1), encephalopathy (n = 1), and acute necrotizing encephalopathy (n = 1). They all were treated with Oseltamivir twice daily for 5 days immediately after nasal and throat swab testing. Twenty-one of the subjects recovered fully, but the youngest two infants experienced severe neurological sequelae. The results indicate that neurologic complications associated with influenza A H1N1 2009 pandemic were mostly mild, but rarely were serious. Prompt intervention leads to a better outcome and vaccination may prevent the disease, thus staving off serious neurological complications following influenza, especially in young infants.

Hospitalizations associated with pandemic influenza A (H1N1) 2009 in asthmatic children in Japan

BACKGROUND

The pandemic influenza A (H1N1) 2009 [pdm (H1N1) 2009] spread through the world in 2009, producing a serious epidemic in Japan. Since it was suggested early that asthma is a risk factor for an increased severity of the infection, the Japanese Society of Pediatric Allergy and Clinical Immunology (JSPACI) organized a working group for countermeasures, and investigated asthmatic children admitted to the hospitals for pdm (H1N1) 2009 infection.

METHODS

An appeal was made on the home page of the JSPACI to medical practitioners to input clinical information about asthmatic and non-asthmatic children (0-19 years) admitted to the hospital with pdm (H1N1) 2009 infection.

RESULTS

A total of 862 children (390 with asthma, and 472 without asthma) from 61 medical centers were registered, and the data of 333 asthmatic children and 388 non-asthmatic children in all were entered in the analyses. The mean age was 7.4 ± 2.9 years in the asthma group and 6.9 ± 3.8 years in the non-asthma group. The percentage of children admitted for respiratory symptoms was significantly higher in the asthma group than in the non-asthma group (p < 0.001). There was no significant difference in the frequency of admission to the ICU or need for mechanical ventilation support between the two groups. No definite trend was detected in the relationship between the severity of asthma and the intensity of asthma attack. Antiviral drugs were administered within 24 hours in about 85% of the patients in both groups.

CONCLUSIONS

Asthma may not be a risk factor for severe pdm (H1N1) 2009 infection in children.

Relationship between the population incidence of febrile convulsions in young children in Sydney, Australia and seasonal epidemics of influenza and respiratory syncytial virus, 2003-2010: a time series analysis

Background

In 2010, intense focus was brought to bear on febrile convulsions in Australian children particularly in relation to influenza vaccination. Febrile convulsions are relatively common in infants and can lead to hospital admission and severe outcomes. We aimed to examine the relationships between the population incidence of febrile convulsions and influenza and respiratory syncytial virus (RSV) seasonal epidemics in children less than six years of age in Sydney Australia using routinely collected syndromic surveillance data and to assess the feasibility of using this data to predict increases in population rates of febrile convulsions.

Methods

Using two readily available sources of routinely collected administrative data; the NSW Emergency Department (ED) patient management database (1 January 2003 - 30 April 2010) and the Ambulance NSW dispatch database (1 July 2006 - 30 April 2010), we used semi-parametric generalized additive models (GAM) to determine the association between the population incidence rate of ED presentations and urgent ambulance dispatches for 'convulsions', and the population incidence rate of ED presentations for 'influenza-like illness' (ILI) and 'bronchiolitis' - proxy measures of influenza and RSV circulation, respectively.

Results

During the study period, when the weekly all-age population incidence of ED presentations for ILI increased by 1/100,000, the 0 to 6 year-old population incidence of ED presentations for convulsions increased by 6.7/100,000 (P < 0.0001) and that of ambulance calls for convulsions increased by 3.2/100,000 (P < 0.0001). The increase in convulsions occurred one week earlier relative to the ED increase in ILI. The relationship was weaker during the epidemic of pandemic (H1N1) 2009 influenza virus.

When the 0 to 3 year-old population incidence of ED presentations for bronchiolitis increased by 1/100,000, the 0 to 6 year-old population incidence of ED presentations for convulsions increased by 0.01/100,000 (P < 0.01). We did not find a meaningful and statistically significant association between bronchiolitis and ambulance calls for convulsions.

Conclusions

Influenza seasonal epidemics are associated with a substantial and statistically significant increase in the population incidence of hospital attendances and ambulance dispatches for reported febrile convulsions in young children. Monitoring syndromic ED and ambulance data facilitates rapid surveillance of reported febrile convulsions at a population level.

Epileptogenic potential of carbapenem agents: mechanism of action, seizure rates, and clinical considerations

Antimicrobials are the most frequently implicated class of drugs in drug-induced seizure, with β-lactams being the class of antimicrobials most often implicated. The seizure-inducing potential of the carbapenem subclass may be directly related to their β-lactam ring structure. Data on individual carbapenems and seizure activity are scarce. To evaluate the available evidence on the association between carbapenem agents and seizure activity, we conducted a literature search of the MEDLINE (1966-May 2010), EMBASE (1974-May 2010), and International Pharmaceutical Abstracts (1970-May 2010) databases. Reference citations from the retrieved articles were also reviewed. Mechanistically, seizure propensity of the β-lactams is related to their binding to γ-aminobutyric acid (GABA) receptors. There are numerous reports of seizure activity associated with imipenem-cilastatin, with seizure rates ranging from 3-33%. For meropenem, doripenem, and ertapenem, the seizure rate for each agent is reported as less than 1%. However, as their use increases and expands into new patient populations, the rate of seizures with these agents may increase. High-dose therapy, especially in patients with renal dysfunction, preexisting central nervous system abnormalities, or a seizure history increases the likelihood of seizure activity. Although specific studies have not been conducted, data indicate that carbapenem-associated seizure is best managed with benzodiazepines, followed by other agents that enhance GABA transmission. Due to the drug interaction between carbapenems and valproic acid, resulting in clinically significant declines in valproic acid serum concentrations, the combination should be avoided whenever possible. Clinicians should be vigilant regarding the possibility of carbapenem-induced seizures when selecting and dosing antimicrobial therapy.

Theobromine and the pharmacology of cocoa

The effects of theobromine in man are underresearched, possibly owing to the assumption that it is behaviourally inert. Toxicology research in animals may appear to provide alarming results, but these cannot be extrapolated to humans for a number of reasons. Domestic animals and animals used for racing competitions need to be guarded from chocolate and cocoa-containing foods, including foods containing cocoa husks. Research ought to include caffeine as a comparative agent, and underlying mechanisms need to be further explored. Of all constituents proposed to play a role in our liking for chocolate, caffeine is the most convincing, though a role for theobromine cannot be ruled out. Most other substances are unlikely to exude a psychopharmacological effect owing to extremely low concentrations or the inability to reach the blood-brain barrier, whilst chocolate craving and addiction need to be explained by means of a culturally determined ambivalence towards chocolate.

Subsequent afebrile seizure in children who have a first seizure with fever after 6 years of age

The objective was to evaluate the risk and the risk factors associated with subsequent afebrile seizures in 31 children who experienced their first seizure with fever after 6 years of age. The children were classified into two groups. Group I comprised children with their first seizure with fever after 6 years of age (n = 15). Group II comprised children who had febrile seizures before 5 years of age and who had recurrent seizures with fever after 6 years of age (n = 16). Of these 31 children, 7 (22.5%) had subsequent afebrile seizure. The cumulative probability of subsequent afebrile seizure was 13.3% at 6 months and 36 months in group I; in group II, the cumulative probability was 12.5% at 6 months, 18.8% at 18 months, 25% at 24 months, and 31.3% at 36 months. There was no significant difference in the risk for subsequent afebrile seizures between the two groups. There were no risk factors associated with an increased risk of subsequent afebrile seizures. If the first seizure with fever occurred after 6 years of age, this was a significant risk for subsequent afebrile seizure; the risk of seizure recurrence in this group appears to be similar to children who have persistent febrile seizures after 6 years of age, but far below that of children with first epileptic seizure.