Valproic acid-induced hyperammonemic encephalopathy with triphasic waves

PURPOSE

To examine a patient with valproic acid (VPA)-induced hyperammonemic encephalopathy accompanied by triphasic waves.

METHODS

A 61-year-old male patient with epilepsy experienced disturbance of consciousness after VPA dose was increased because of poor seizure control. The electroencephalogram (EEG) taken on admission revealed triphasic waves and high-amplitude delta-activity with frontal predominance. Although serum hepatic enzymes, such as AST and ALT, were normal, serum ammonium level was high at 96 microg/dl (normal range, 3-47 microg/dl). Serum amino acid analysis showed multiple minor abnormalities. Administration of VPA was discontinued immediately after admission, while other anticonvulsants were continued.

RESULTS

The patient's condition was improved on the fourth day of admission. An EEG, serum ammonium level, and amino acid profile were normal on the eighth day. Based on VPA administration, serum ammonium levels, and results of amino acid analysis, this patient had VPA-induced hyperammonemic encephalopathy.

CONCLUSIONS

Our case indicates that caution is required if triphasic waves appear in VPA-induced hyperammonemic encephalopathy.

Bone mineral density of epileptic patients on long-term antiepileptic drug therapy: a quantitative digital radiography study

In order to assess the bone atrophy lesions of epileptic patients, the bone mineral densities (BMDs) of their lumbar spines and femoral necks were measured using quantitative digital radiography (QDR). The study groups were 44 patients on long-term medication for epilepsy and 62 healthy control subjects. We selected patients who had been taking phenytoin, barbiturates, and/or acetazolamide for at least 5 years. BMDs at both sites were significantly lower in the patient group than in the control group. No sex differences were found in BMDs. There were no significant correlations with the onset or the duration of illness and BMD. We compared BMD according to the type of epileptic drug being taken and theorized that phenytoin, barbiturates, and acetazolamide reduced BMD. BMDs of the 15 patients were measured again 7 years later, and were found to be significantly lower at both sites than in the previous examination. These results confirm the presence of bone atrophy lesions in epileptic patients on long-term antiepileptic drugs. Patients on antiepileptic therapy for long periods should have their BMDs checked, because they are prone to developing bone atrophy.

Non-convulsive status epilepticus induced by antidepressants

We report on a 27-year-old woman of non-convulsive status epilepticus (NSE) very probably induced by antidepressants. She has no history of febrile convulsions, or epileptic seizures. There are no genetic factors for epilepsy in her family. As she developed depressive illness, she consulted a doctor. Clomipramine 25 mg i.v. drip/day and maprotiline 75 mg/os/day were started. Recently she began to doze, so an EEG was performed. Continuous generalized 2-3 Hz spike and wave complexes were observed. Clomipramine and maprotiline were stopped the same day, and the patient's drowsiness gradually improved. There are some case reports of NSE induced by antidepressants. However, the patients in these reports had received frequent electroconvulsive therapy (ECT) and were middle aged and may have been affected by an organic brain disorder. The present patient was young, and had not received ECT. It is therefore very likely that antidepressants may have been responsible for the occurrence of NSE in this patient. It is concluded that NSE should be considered an adverse effect of any antidepressant.

[Modification of stereotypy-producing and ambulation-increasing effects following repeated administration of methamphetamine in rats]

Effects of repeated administration of methamphetamine (MAP: 1.25, 2.5 and 5 mg/kg, sc) at an interval of 4 days for 10 times on stereotyped behaviors as well as ambulatory activity in adult male rats of Wistar strain were investigated. In the first administration of MAP 1.25 mg/kg, marked ambulation-increasing effect was observed mixing with simple stereotyped behaviors such as sniffing and head-bobbing. The stereotypy-producing effect of MAP was apparently observed in a dose-dependent manner, and complicated stereotyped behaviors such as head-weaving and licking simultaneously with sniffing and head-bobbing were frequently demonstrated when 5 mg/kg of MAP was first administered. Furthermore, the ambulation-increasing effect after the drug showed biphasic pattern, i.e. pre-stereotypic and post-stereotypic increases in ambulatory activity, because the activity was interfered by the stereotyped behaviors. When MAP was administered repeatedly, the sniffing- and head-bobbing-producing effects were selectively enhanced at any dose, showing sensitization phenomenon (reverse tolerance), and the pre-stereotypic increase in ambulatory activity was inhibited, while the post-stereotypic increase was progressively enhanced. Although the sensitized stereotypy-producing effect was observed more markedly in the 10th administration of MAP 2.5 mg/kg than that in the first administration of MAP 5 mg/kg, the complicated stereotyped behaviors were hardly seen. It is suggested that the sensitization effects are not always identical qualitatively with the effects observed after increase in MAP-dose.

Enhancement of prolactin-secreting effect produced by repeated administration of haloperidol in the avoidance situation and dopamine neurons in rats

Male Wistar strain rats subcutaneously administered haloperidol at the dose of 0.035 mg/kg at 3-4 days interval, 10 times, in the avoidance situation. Enhancement of the prolactin-secreting effect of haloperidol was observed when it was given in the home cages at the 10th day after termination of the repeated administration. In these animals, 3H-spiperone binding sites in the pituitary significantly increased, while the DOPAC/DA ratio in the hypothalamus significantly decreased. The enhancement phenomenon may be produced by a decrease in the activity of dopamine neurons in the hypothalamus.

Contributions of baroreceptor reflex to the hypothermic effect of intraventricular angiotensin II in rats

The mechanisms of the hypothermic effect of angiotensin II (AII) injected into the lateral ventricle were investigated in unanesthetized rats at an ambient temperature of 18 degrees C. Mean blood pressure (BP), heart rate (HR), metabolic rate (M), colonic temperature (Tcol), and temperatures of the interscapular brown adipose tissue (TBAT), and the tail skin (Tsk) were continuously monitored. AII at a dose of 5 micrograms produced a sharp and marked elevation in BP accompanied by bradycardia, and a decrease of M and Tco1 in the sinoaortic baroreceptor intact rats. The difference between TBAT and Tcol decreased significantly, which suggests a suppression of nonshivering thermogenesis of the BAT. Tsk was not changed by the AII injection. After sinoaortic denervation, however, the decrease in Tcol and M with AII injection was significantly reduced despite a marked elevation in BP. In addition, intravenous arginine-vasopressin antagonist pretreatment suppressed the elevation in BP and the decrease in HR, Tcol, and M after AII injection. From these results, it is concluded that the hypothermia which occurred after AII injection into the lateral ventricle can be largely attributed to the baroreflexive suppression of M, and to some extent to the direct effect on the thermoregulatory center in rats.

Baroreflexive suppression of heat production and fall in body temperature following peripheral administration of vasopressin in rats

Intravenous injection of vasopressin (lysin-8-vasopressin, LVP) in unanesthetized rats at an ambient temperature of 18 degrees C caused a decrease in heat production (M) followed by a fall in colonic temperature (Tco1). These changes were preceded by an elevation of aortic blood pressure (BP) and bradycardia, and were related to the dosage of LVP administered. Temperature of the interscapular brown adipose tissue (BAT) significantly fell after LVP injections. Therefore, it can be said that the decrease in metabolism by the peripheral LVP is at least partly due to suppression of BAT thermogenesis. After bilateral sino-aortic deafferentation, however, the changes in these variables were greatly but not completely reduced except for the elevation of BP. LVP of 0.25 micrograms, more than sufficient to cause a significant elevation of BP when administered peripherally, had no effect on M and Tco1 when injected into the anterior hypothalamus. From these results, we conclude that the hypothermic effect of vasopressin administered peripherally is largely attributed to the baroreflexive suppression of nonshivering thermogenesis, and is not due to the action on the temperature regulatory centers. The slight but insignificant suppression of metabolism in the sinoaortic denervated rats following injection of LVP may be caused by a decreased blood flow to the thermogenic tissues.