Biomedical subjects
Publications and source records attributed to M Mikati.
Mycotic aneurysms are rare complications in patients with infective endocarditis, particularly in the pediatric population. We report a case of mycotic aneurysm of the middle cerebral artery complicating bacterial endocarditis in a child with Down's syndrome. The patient was successfully treated medically without the need for surgical intervention.
Lamotrigine is a new antiepileptic drug that is effective for a broad range of seizures in adults and children. Three children with seizures of different causes who were treated with lamotrigine and developed reversible hepatotoxicity are reported. In one child, this therapy led to relatively severe hepatic failure that required and responded to aggressive therapy. Unlike most of the previously reported six patients with similar severe hepatic involvement, this patient's liver function and blood hepatic enzymes became normal. All three patients were on multiple drugs, and two were in epilepsia partialis continua secondary to encephalitis. Two of the patients had relatively rapid medication titration schedules. The close time relationship between the initiation of the lamotrigine therapy and the reversal of the liver abnormalities with lamotrigine discontinuation argues against a cause other than the lamotrigine; however, because of the complexity of the reported cases, the causality remains an assumption. Review of the literature revealed six other previously reported patients (five adults and one child) who had hepatotoxicity during lamotrigine therapy, with or without associated multisystem failure, and similar patient profiles. Lamotrigine is generally a safe and effective medication; however, it should be used with caution in patients on polytherapy and in those with complicated acute systemic and central nervous system conditions, such as fever, status epilepticus, epilepsia partialis, and encephalitis.
We report an 8-year-old boy with complex partial seizures due to congenital stroke, treated with valproate for more than 3 years (the last 2 years were on monotherapy) with no complications during that period except for transient thrombocytopenia. His sister had uncomplicated hepatitis A. One month later, the patient became jaundiced, went into fulminant hepatic failure, and quickly became encephalopathic despite discontinuation of valproate, aggressive supportive therapy, and treatment with carmitine. He then died. He had positive hepatitis A IgM; other causes for acute hepatitis were ruled out. Liver pathology revealed distended hepatocytes with cholestasis and microvesicular changes. We could find in the literature two other articles on four cases who developed liver failure with hepatitis A while on valproate. All those cases, however, recovered. In our patient a usually benign disease became deadly, probably because of the concomitant use of a hepatotoxic medication. Immunizing, with hepatitis A vaccine, all children on valproate therapy who are living in, or traveling to, endemic areas should be considered and is probably advisable.
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Postnatal exposure to steroids has been associated with hypertrophic cardiomyopathy (HCM) in the newborn. Such an effect has not been described in infants born to mothers who received antenatal steroids. We report three newborns whose mothers were treated with betamethasone prenatally in different doses, duration of time, and who developed various degrees of HCM diagnosed by echocardiography. There was no maternal evidence of diabetes except for one infant whose mother had a normal fasting and post-prandial blood glucose prior to steroid therapy, but an abnormal one hour postprandial glucose after 8 weeks of betamethasone therapy, with a normal HbA1 C level. There was no family history of HCM, no history of maternal intake of other relevant medications, and no hypertension in all three newborns. Follow-up echocardiography revealed complete resolution of the HCM changes in all infants. We suggest that repeated antenatal maternal steroid intake may cause changes of HCM in the newborn. These changes appear to be dose- and duration-related and are mostly reversible. Further prospective controlled studies to evaluate these observations and to investigate potential mechanisms are warranted.
Adrenoleukodystrophy (ALD) is an X-linked inherited disorder of lipid metabolism usually presenting in childhood or early adolescence. It is a progressive disease with symptoms of adrenal insufficiency and central nervous system demyelination. The pathology results from the accumulation of very long-chain fatty acids and an inflammatory reaction in the brain white matter. We report a case of ALD associated with adrenal insufficiency and two autoimmune diseases: vitiligo and ulcerative colitis.
OBJECTIVE: To investigate the long-term effects of two widely used antiepileptic medications, valproate and phenobarbital, on learning and behavior in the kainic acid (KA) model of epilepsy. BACKGROUND: Prior clinical and animal studies have demonstrated that phenobarbital administered during development may result in subsequent cognitive impairment. It is unclear whether these adverse effects of phenobarbital extend to other antiepileptic drugs. METHODS: A convulsant dose of KA was administered to rats on postnatal day (P) 35. From P36-75 rats received daily injections of phenobarbital (PH), valproate (VPA), or saline and spontaneous seizure frequency was monitored with video recordings. After tapering of the drugs, the rats were tested in the water maze (a measure of visuospatial memory) and handling test (a measure of emotionality). Brains were then analyzed for histologic lesions. RESULTS: KA caused status epilepticus in all the rats. In the PH- and saline-treated groups, there was impaired learning in the water maze, increased emotionality, recurrent seizures, and histologic lesions in the hippocampal areas CA3, CA1, and dentate hilus. However, VPA-treated rats had no spontaneous seizures, abnormalities in handling, or deficits in visuospatial learning, and had fewer histologic lesions than animals receiving KA alone. CONCLUSIONS: The long-term consequences of AED treatment during development are related to the drug used. VPA treatment after KA-induced status epilepticus prevents many of the neurologic sequelae typically seen after KA.
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PURPOSE: Although several treatments have been tried for Landau-Kleffner syndrome (LKS) too many patients are refractory to known therapies. We report an 8-year-old girl who failed other therapies but who had a consistent response after treatment with intravenous (i.v.) gamma-globulin. METHODS: We monitored the girl from the age of 6 years, when she presented with a 6-month history of loss of language with normal hearing, normal brain magnetic resonance imaging (MRI), increased cerebrospinal fluid (CSF) IgG index, and an EEG showing almost continuous, predominantly left-sided spike- and slow-wave complexes. She had no clinical seizures and did not respond to consecutive trials of valproate (VPA), clonazepam (CZP), prednisone, and carbamazepine (CBZ). She received three courses of intravenous (i.v.) gamma-globulin; after each course, clinical and electrographic improvement lasted a few months. After each of the initial two courses, clinical improvement lasted 3-4 months but was followed by recurrence of the spikes on the EEG and by speech deterioration. RESULTS: However, her last remission has been continuous for the past 16 months. Her CSF IgG index became normal after the first i.v. gamma-globulin infusion. CONCLUSIONS: Based on our experience with this patient and on other investigators' experience, we believe that further research into immunologic mechanisms and therapies of this syndrome are warranted.
Because of the critical role of excitatory amino acids (EAAs) in epileptogenesis and seizure-induced brain damage, EAA antagonists are now being considered as a possible therapy for seizures. However, during development EAAs play a pivotal role in learning, memory, and brain plasticity. To evaluate the long-term effects of a short course of EAA antagonists on the developing brain, a non-NMDA antagonist, NBQX, or a NMDA antagonist, MK-801, were administered over 7 days by osmotic pumps stereotaxically implanted into the lateral ventricles of normal 10 day old rats. Alternatively, 10 and 20 day old rats received a 7 day course of intraperitoneal (i.p.) NBQX. One month later, the NBQX-, MK-801-treated rats, and controls underwent a series of behavioral studies: handling test, open field, and Morris water maze. Flurothyl inhalation was used to test seizure susceptibility in all groups. Although all of the rats treated with NBQX via osmotic pumps has spontaneous seizure, rats surviving infusion of EAAs had no deficits in learning, memory, or behavior and did not differ from controls in seizure susceptibility with flurothyl. In the developing animal, a short-term course of EAA antagonists leads to no long-term adverse effects on behavior or seizure susceptibility.
Mesial temporal sclerosis (MTS) is a common pathologic finding in patients with temporal lobe epilepsy. Rarely MTS can be detected in children during the first decade of life, but is not commonly found until adolescence. Although the etiology of MTS remains controversial, there is now a considerable amount of evidence demonstrating that MTS is both a result and a cause of seizures. Clinical studies suggest that prolonged seizures or complicated febrile seizures may result in MTS. A variety of epileptogenic agents administered to adult animals have resulted in MTS and spontaneous recurrent seizures. The mechanism of the lesions is due to excessive excitability secondary to release of excitatory amino acids, primarily glutamate. Glutamate, acting at a number of subreceptors on the postsynaptic membrane, leads to prolonged depolarization of neurons and results in the entry of cytotoxic amounts of calcium. Interestingly, the same agents that produce MTS in adult animals do not produce MTS in immature animals. Clinical and experimental evidence suggests that although prolonged seizures or complicated febrile seizures can place a child at risk for MTS, a period of time is required for the lesions to develop fully.
For patients with intractable seizures, the best surgical outcome is achieved following precise localization of the seizure focus. Scalp EEG monitoring may be insufficient and chronic subdural invasive EEG monitoring has therefore been advocated. At Children's Hospital in Boston, 31 children had chronic subdural monitoring from January 1990 through June 1994. The average age at implantation was 11 years. Most patients (22) had placement of grid electrodes combined with strip electrodes to map temporal and/or frontal regions bilaterally. Twenty of the patients eventually had a resective procedure based on the findings. During monitoring, cortical stimulations were performed to localize speech and somatosensory areas. There was only one complication, a subdural hematoma in a patient who had had previous surgery. Chronic subdural EEG monitoring is helpful in precisely localizing seizure foci in pediatric patients; it also allows motor and speech mapping and appears to be a safe modality in children.
This article reviews the preoperative evaluation of the child with intractable epilepsy. The importance of the history and the clinical manifestations of the seizures, and the results of electrophysiology, neurophysiology, and neuroimaging studies are discussed.
Clotrimazole (CLT) has recently been shown to be a potent and specific inhibitor of the Ca(2+)-activated K+ channel and to thereby prevent K+ loss and cellular dehydration of sickled erythrocytes. This evidence suggests that oral CLT may be a useful new therapy for sickle cell disease. Here, we describe the development of an HPLC assay to measure CLT, a method we used to study the pharmacokinetics and transport of CLT in normal volunteers. The assay's linear range extended to 10 mumol/L; the detection limit was 0.1 mumol/L, analytical recovery 97.7%, and run-to-run imprecision (CV) < 4.7%. In unaffected subjects, CLT concentration peaked within 6 h of oral administration and returned to close to baseline by 24 h. High-density lipoproteins appear to be the main carriers of this drug in both normo- and hypertriglyceridemic plasma. We conclude that the method described here is ideally suited for therapeutic monitoring of CLT concentrations.
The National Institutes of Health sponsored a randomized, double-blind, multicenter, placebo-controlled trial of flunarizine (FNR) in epileptic patients receiving concomitant phenytoin (PHT) or carbamazepine (CBZ). Because of FNR's long half-life (up to 7 weeks), a parallel rather than crossover design was used. Each patient received an individualized loading dose and maintenance dosage targeted at a 60-ng/ml plasma FNR concentration. Of 93 patients randomized, 92 provided seizure data for the full 25-week treatment period; one placebo-treated patient dropped out for personal reasons. Fifty-four patients received CBZ only, nine received PHT only, and 30 received both CBZ and PHT. Eighty-seven patients had a history of complex partial seizures, and 60 had secondarily generalized seizures. Eight patients discontinued FNR prematurely, all because of adverse neurologic or psychiatric signs or symptoms; depression was the specific cause in three cases. Calculated maintenance dosages, based on single-dose pharmacokinetic profiles, ranged from 7 to 138 mg/day (mean, 40 mg/day). Plasma FNR concentrations generally exceeded the target, with the highest concentrations observed immediately after loading; excluding the first three treatment weeks and all concentrations after a FNR dosage change, the median plasma FNR concentration was 71.7 ng/ml. The percent reduction from baseline seizure rate was statistically greater (p = 0.002) in the FNR-treated group (mean, 24.4%) than in the placebo-treated group (mean, 5.7%).
Felbamate, a newly developed antiepileptic agent, has been demonstrated to control partial and generalized seizures effectively. We have developed a gas-chromatographic method for the determination of felbamate, using a wide-bore capillary column, a flame ionization detector, and a simple extraction procedure. The assay day-to-day precision (n = 20) was 5.2% and 3.6% for drug concentrations of 50 and 150 mg/L, respectively; average recovery over a wide range of felbamate concentrations was 95%; the detection limit was 5 mg/L; and assay linearity extended to 300 mg/L. Although 9 of the 27 drugs tested were coextracted with felbamate, they exhibited significantly different retention times and showed no interference. A short-term stability study showed that plasma felbamate is stable at 4, -20, or -78 degrees C for at least 1 month. Plasma felbamate concentrations in 66 pediatric patients ranged from 7 to 154 mg/L (mean +/- SD 44 +/- 24.7). We consider the method ideally suited for therapeutic monitoring of plasma felbamate concentration.
The effects of body temperature on kainic acid-induced seizures and seizure-related brain damage were examined in rats. In rats with status epilepticus induced by intraperitoneal injection of 12 mg/kg of kainic acid (KA), ictal discharges were decreased by 50% when body temperature was lowered to 28 degrees C and nearly abolished when body temperature was lowered to 23 degrees C. In rats with mild hypothermia (28 degrees C), the duration of ictal discharges following KA injection was significantly lower than in rats with normal body temperature. No detectable hippocampal cell loss was observed in rats with hypothermia to 28 degrees C whereas gross cell loss in the hippocampus was observed in all rats with KA injection at normal body temperature. In contract to hypothermia, hyperthermia markedly aggravated the seizures and hippocampal damage induced by KA. Following elevation of body temperature to 42 degrees C KA (12 mg/kg) resulted in severe seizures and all rats died of tonic seizures within 2 h. Furthermore, 6 mg/kg of KA administered to rats with a body temperature of 41-42 degrees C, resulted in up to 4 h of continuous ictal discharges whereas no continuous ictal discharges were observed after the same injections in rats with normal body temperature. Histological examination in rats receiving 6 mg/kg of KA revealed severe cell loss in the hippocampus in rats with hyperthermia but not in rats with normal temperature. These results demonstrate that body temperature plays an important role in the control of epileptic seizures and seizure-related brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)
Basic fibroblast growth factor (bFGF) has been shown to have neuroprotective effects in animal models of ischemia. To determine whether bFGF is protective against seizure-induced brain damage, we administered bFGF through osmotic pumps prior to, and after treatment with kainic acid (KA). Recombinant bFGF, CS23, a modified human bFGF, was infused into the lateral ventricles in rats for 2 days before and 5 days after the injection of KA. Control rats received equal volumes of phosphated saline over the same period of time. Infusion of 5 micrograms/ml of bFGF (0.5 microliter/h) did not modify the latency and duration of seizures induced by intraperitoneal injections of KA. However, bFGF prevented cell loss in the hippocampus in 80% of the rats. In control rats, cell loss in the hippocampus was found in all rats. These results indicate that bFGF has a substantial neuroprotective effect.