Indian Write- Ups

Discussion

Epilepsy forms the largest group requiring long-term anticonvulsive therapy. Though these patients come out of agony but are predisposed to various untoward effects1. The use of antiepileptic drugs are associated with secondary changes in the levels of serum lipids with its possibleimplications of atherogenic vascular diseases like coronary artery2, ischaemic cerebrovascular3 and peripheral vascular diseases4. However, clinicians working on epilepsy have observed decreased incidence of coronary artery disease and sudden deaths in epileptics on long-term anticonvulsive therapy5, 6, 7 and proposed favorable changes in serum lipid pattern as one of the factors involved8, 9, 10.

The significant rise of HDL-C at 12 and 24 weeks of phenobarbitone therapy in our study is consistent with other observations in epileptics11, 12. Our observation of pronounced effect in female compared to male, has bot been established but female sex hormones are known to affect lipid metabolism which in turn ma be responsible for higher levels of HDL-C in female. The observations of no significant increase in levels of TC, LDL-C, VLDL-C, PL and TG with long-term phenobarbitone therapy have also been reported in epileptic patient13, 14, healthy volunteers15 and animals studies16. However, as against our study a significant rise in levels of TC, TG and LDL-C after penobarbitone therapy for 13 - 18 days have also been observed in a study, comprised of only 4 patients16. The increase in levels of TC and TG are associated with increased levels of LDL-C and vice-versa and perhaps a larger sample size with longer duration of study could have improved the statistical significance of the said study.

Presently the precise mechanism as to how phenobarbitone is implicated in the causation of increased HDL-C in epileptic is difficult to explain but induction of microsomal enzyme system in liver may be an important factor in determining plasma lipid concentration17, 18.

References

• Reynolds E. H. - Drug treatment of epilepsy, Lancet ii, 30, 721-726, 1978.
• Jenkins P. J., Harper R. W., Nestel P. J. - Severity of coronary atherosclerosis related to lipoprotein concentration. BMJ, 2, 338-394, 1978.
• Rossner S., Mettinger K. L., Kjellin K. G. et al. - Normal serum cholesterol but low HDL concentration in young patients with Ischemic cerebro-vascular disease. Lancet, 18, 577-579, March 1978.
• Bradby G. V. H., Valante A. J., Walton R. W. - Serum high-density lipoproteins in peripheral vascular diseases. Lancet, 2, 1274-1279, 1978.
• Lindin V. - Myocardial infarction in epileptics. BMJ, 2, 87-91, 1975.
• Livingston S. - Phenytoin and serum cholesterol. BMJ, 1, 586-591, 1976.
• Murronen A., Kaste M., Nikkila E. A. et al. - Mortality from Ischemic Heart disease among patients using anticonvulsive drugs: a case control study. Br. Med. J., 291, 1481-1485, 1985.
• Nikkila E. A., Kaste M., Ehnholm C. et al. - Elevation of high-density lipoprotein in epileptics treated with phenytoin. Acta Med. Scand., 204, 517-520, 1978.
• Lumoa P. V., Reunanen M. I., Sotaniemi - Changes in serum triglyceride and cholesterol levels during long-term phenytion treatment for epilepsy. Acta Med. Scand., 206, 229-231, 1979.
• Kasta M., Murronen A., Nikkila E. A. et al - Increase of low serum concentration of HDL-cholesterol in TIA patients treated with phenytoin. Stroke, 14 (4), 525-530, 1983.
• Durrington P. N. - Effect of phenobarbitone on plasma apolipoprotein B and plasma HDL-cholesterol in normal subjects. Clin Sci, 56, 501-504, 1979
• Reddy M. N. - Effect of anticonvulsant drugs on plasma cholesterol, HDL cholesterol and apolipoprotein A and B in children with epilepsy. Proc. Soc. Exp. Biol. Med., 180, 359-363, 1985.
• Linden V., Brevik J. I. and Hansen T. - Phenytoin phenobarbitone and serum cholesterol. Scand J. Soc. Med., 5, 123-127, 1977.
• Bhatia M. S., Balkrishna, Singhal P. K. and Kaur N. - Effect of Diphenylhydrantoin on serum cholesterol in epileptic patients. Ind. Med. Gaz. Jan., 8 - 9, 1988.
• Ohnhaus E. E. Kirchhof B., Peheim E. - Effect of enzyme induction on plasma lipids using antipyrine, phenobarbital and rigampicin. Clin. Pharm. Ther., 25, 519-567, 1979.
• Myabnikov A. L. - Influence of some factors on developmental cholesterol atherosclerosis. Circulation, 17, 99, 1985.
• Miller N. E., Nestel P. J. - Atteredible acid metabolism during treatment with phenobarbitone. Clin. Sci. Mol. Med., 45, 257, 1973.
• Kuntzman R. - Drugs and enzyme induction. Annual Review of Pharmacology, 9, 21-36, 1969.

Precise Radio-surgery Controls Brain Tumors

A High-precision radio-surgery technique capable of controlling a third of all brain tumors has been developed by clinicians at the Institute of Cancer Research and the Royal Marsden Hospital, in the United Kingdom.

Known as conformal stereotactic radiotherapy, the technique delivers precise irradiation treatment with surgical accuracy. It combines the latest advances in shaped - beam radiotherapy and three-dimensional scanning methods, enabling doctors to reach and treat tumors buried deep in the brain.

Although conventional radiotherapy is able to control up to 90 per cent of localised benign tumors some patients suffer brain damage. Dr. Michael Brada of the Royal Marsden claims that the technique will allow even more of these tumors to be treated with high-precision radiation without the risk of life-changing side-effects. This is of particular importance when the tumors develop in children because conventional radiotherapy can damage the developing brain and lead to severe mental impairment.

Although relatively rare, brain tumors are the most common solid tumors in children. In adults they are second only to stroke as the leading cause of death from neurological disease. About one third are localised tumors occurring deep in the brain - and treatable only with radiotherapy which can be administered much more safely and accurately with the new technique which avoids irradiating healthy brain tissue.

The first stage involves an accurate image of the patient's brain using a combination of magnetic resonance imaging and standard computerised tomography scans.

The information is fed into sophisticated computers that create an individualised treatment plan. Precise dimensions for irradiation are essential because about 95 per cent of brain tumors are not uniformly spherical.

Advanced sterepotactic radiotherapy equipment is then used to target precise radiation to tumors deep in the brain. This involves the use of a specially designed frame that is strapped to the head without the use of an anaesthetic.

A "fractionated" form of radiation beam is used and is less damaging to normal brain tissue. The treatment is particularly suitable for skull base tumors where brain stem cells are close to the malignancy.