Decreased bone mass and increased bone turnover with valproate therapy in adults with epilepsy

BACKGROUND

Bone loss and hypovitaminosis D are reported in patients taking antiepileptic drugs, but little is known about changes in bone and calcium metabolism from valproic acid (VPA).

OBJECTIVE

To assess the relationship of VPA to bone mass and calcium metabolism in 40 adults with epilepsy on long-term VPA monotherapy, 40 age- and sex-matched epileptic patients taking phenytoin (PHT), and 40 healthy control subjects. Bone mineral density (BMD) of the second metacarpal was determined as T- and Z-scores.

RESULTS

BMD reduction from control values was 14% (12% in men, 16% in women) with VPA and 13% (12% in men, 15% in women) with PHT. Among patients on VPA, nine (23%) had T-scores below -2.5 SD, suggesting osteoporosis; 15 (37%) had T-scores between -1 and -2.5 SD, suggesting osteopenia. Serum concentrations of calcium were significantly higher with VPA than in PHT or control groups. Serum concentrations of bone Gla protein (a bone formation marker) and pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker) associated with either drug significantly exceeded control values. Z-scores for BMD in the VPA group correlated negatively with calcium and ICTP. High ICTP correlated positively with ionized calcium, implying that increased bone resorption caused the latter.

CONCLUSION

Long-term VPA monotherapy can increase bone resorption, leading to decreased BMD.

[Ictal visual hallucination intermittent photic stimulation: using evaluation of the clinical findings, ictal EEG, ictal SPECT, and rCBF]

A 43-year-old, right-handed woman experienced right hand paresthesias and a visual field abnormality. We attributed her symptoms to psychiatric abnormalities, due to the presence of delusions and auditory hallucinations. Upon photostimulation, she experienced left visual field hallucinations and demonstrated slow waves on the right parieto-occipital regions. The clinical and electro-encephalographic findings suggested that these episodes were epileptic seizures originating from the right occipital region. Ictal fear appeared at the end of the seizure, reflecting the spread of seizure activity to the mesial temporal region. Ictal SPECT images showed hyper-perfusion in the right occipital region and left cerebellar cortex. rCBF in the occipital lobe was significantly asymmetrical. When we encounter an epileptic patient with psychosis who has a visual hallucination, we should consider the possibility of epileptic seizure originating from the occipital lobe.

Prognosis of epilepsy withdrawn from antiepileptic drugs

Antiepileptic drugs (AED) were discontinued in 55 epileptics who had been free from seizures treated with AED, in accordance with the following criteria and procedures. (i) A reduction in AED commences when patients have been free from seizures for at least 2 years and epileptic discharges have also disappeared in repeated electroencephalogram (EEG) recordings during that period. (ii) AED are gradually reduced if no relapse is seen in clinical seizures and epileptic discharges in EEG. (iii) As a rule at least 2 years are required as the interval from the onset of a reduction to the withdrawal of AED. Forty-three patients were followed up by a questionnaire and/or by telephone and the follow-up period from the withdrawal of AED to the survey ranged from 0.9 to 8.8 years; in 38 patients (88.4%) the period was longer than 2 years. No relapse of seizures was found in any of the 43 patients. The severity of epilepsy judged by the total number of frequency of seizures, the presence of neuropsychiatric complications, the combination of different types of seizures, and the duration of epilepsy from the seizure onset to the last seizure appeared not to be risk factors for the recurrence of seizure. Normal EEG was, however, considered to be an important prerequisite for a good prognosis.