DOES A BANANA A DAY KEEP STROKE AWAY?

Low potassium intake and low potassium serum levels, already associated with increased stroke mortality in numerous studies, have now been linked to increased stroke incidence in a prospective cohort study investigating serum potassium levels, dietary potassium intake, and diuretic use in relation to stroke risk.

The study, composed of 5,600 men and women 65 years or older who were free of stroke at baseline, appeared in the August 13 Neurology. A medical history and physical examination were obtained, and baseline testing included fasting blood sugar, potassium, and creatinine levels, an electrocardiogram, an echocardiogram, and carotid ultrasound studies. Low serum potassium was defined as less than 4.1 mEq/L, and low potassium intake was defined as less than 2.4 g/d. The subjects were followed for four to eight years, and incident strokes were determined by questions at annual clinic visits.

During the four-to-eight-year observational period, there were 473 strokes, “404 of which were ischemic, 50 hemorrhagic (including both subarachnoid and intraparenchymal) and 19 not clearly classifiable.” The risk of stroke was associated with lower serum potassium levels only in participants on diuretics and was associated with low dietary potassium only in those not on diuretics. For individuals not taking diuretics, the lowest quintile of potassium intake (2.34 g/d or less) was associated with an increased risk for stroke when compared with the diuretics group, when potassium intake was 4.17 g/d or greater.

Researchers were unable to determine if low serum potassium or low dietary potassium intake had a direct causal relationship to increased stroke risk. Additionally, they were uncertain as to why low potassium intake affected the risk of stroke only in those patients not taking diuretics and why low serum potassium levels affected the risk of stroke only for those who were taking diuretics.

Suggested Reading
Green DM, Ropper AH, Kronmal RA, et al. Serum potassium level and dietary potassium intake as risk factors for stroke. Neurology. 2002;59:314-320.

EVALUATION AND MANAGEMENT OF REPRODUCTIVE DISORDERS IN WOMEN WITH EPILEPSY

Seizure control is the primary goal for treating epilepsy, but when treating women with epilepsy, additional factors need to be considered. Antiepileptic drugs have been shown to interfere with the hormones and reproductive cycles of women, and in an article appearing in the August Journal of Neurology, Neurosurgery, and Psychiatry, researchers suggested that in the presence of a reproductive endocrine disorder, “antiepileptic drug treatment should be reviewed to ensure that it is correct for the particular seizure type and that it is not contributing to the endocrine problem.”

The investigators described several prevalent reproductive endocrine disorders in women with epilepsy. While polycystic ovary syndrome has been reported to affect 4% to 6% of women in the general population, the prevalence of the disorder in women with temporal lobe epilepsy has been found to be between 10% and 25%. Hypothalamic amenorrhea was found in 12% of 50 women with temporal lobe epilepsy, although it is estimated to affect only 1.5% of the general population. Early menopause was reported in 14% of 50 women with temporal lobe epilepsy, compared with 4% of age-matched controls.

Researchers determined that there were four highly probable explanations for the relationship between reproductive endocrine disorders and epilepsy. The lesions that result from epilepsy or the antiepileptic drugs may alter the endocrine controls in the brain, which can cause the frequently seen “acute changes in serum prolactin and gonadotropin levels following seizures.” Antiepileptic drugs, particularly valproate, have been known to affect peripheral endocrine glands in animal models, altering sex steroid levels and increasing the number of follicular cysts in rats. Antiepileptic drugs also have a negative effect on the metabolism of hormones, decreasing or increasing biologically active serum sex hormone levels. Weight changes that result from drug treatment reduce insulin sensitivity, making women more prone to polycystic ovary syndrome.

The researchers concluded that physicians need to be aware that reproductive endocrine dysfunction may occur in women with epilepsy, and if a disorder is found, “the possible benefits of a change in treatment must be balanced against seizure control and the cumulative side effect of alternative agents.” Physicians should also monitor patients’ reproductive functions to exclude the possibility of menstrual disorders or fertility problems.

Suggested Reading
Bauer J, Isojarvi JIT, Herzog AG, et al. Reproductive dysfunction in women with epilepsy: recommendations for evaluation and management. J Neurol Neurosurg Psychiatry. 2002;73:121-125.

MORE CALORIES AND FATS ASSOCIATED WITH HIGHER RISK OF ALZHEIMER’S DISEASE

Consuming more calories and fats may contribute to an increased risk of Alzheimer’s disease in people with the apolipoprotein E (APOE) epsilon4 allele. Researchers believe that the relationship between caloric restriction and a longer life span is a result of the production of fewer free radicals—destructive molecules formed during the breakdown of food and oxygen in cells. Free radicals damage cells and may increase the damage done by beta amyloids.

Investigators studied the association between caloric intake and Alzheimer’s disease in 980 elderly subjects (average age, 75.3) with no clinical diagnosis of dementia at baseline. The researchers followed the patients for an average of four years and recorded how many calories they consumed. The average daily caloric intake of the women studied was 1,267 kcal, while men consumed an average of 1,316 kcal per day. The average daily fat consumption in both groups was 38 grams.

The researchers divided the participants into four groups according to how many calories were consumed daily. During the study, 242 patients developed Alzheimer’s disease. Investigators determined that the relationship between a diet high in calories and fat and the development of Alzheimer’s disease was not statistically significant.

However, 263 of the participants were homozygous or heterozygous for the APOE epsilon4 gene, and among them, those who consumed the most calories had a 2.3 times greater chance of developing Alzheimer’s disease compared to those who ingested the fewest calories. Researchers determined that a high intake of total calories and fats in elderly individuals is associated with a higher risk of Alzheimer’s disease only in carriers of the APOE epsilon4 allele. The results of the study were published in the August Archives of Neurology.

Suggested Reading
Luchsinger JA, Tang MX, Shea S, Mayeux R. Caloric intake and the risk of Alzheimer disease. Arch Neurol. 2002;59:1258-1263.

UNDERSTANDING ANTHRAX MENINGOENCEPHALITIS

Even with aggressive polydrug treatment, the survival rate for anthrax meningoencephalitis remains very poor. Survival is most likely if the meningoencephalitis develops from cutaneous anthrax and if treatment begins before the disease is clinically advanced. Douglas J. Lanska, MD, MS, MSPH, Chief of Staff for the Veterans Affairs Medical Center, Tomah, Wisconsin, conducted a retrospective review of articles reporting cases of anthrax meningoencephalitis during the previous 50 years. He sought to describe the clinical findings, diagnostic test results, treatment, and outcome of these cases in the August 13 Neurology.

Reports were selected if they “provided patient-specific clinical information, with confirmation of meningoencephalitis, and either microbiological or pathologic confirmation of anthrax infection.” Dr. Lanska identified 70 cases from 34 reports. Of these 70 cases, 77% were male, and the age of cases ranged from 2 to 72. A probable source of exposure was reported in 49 cases (70%). Dr. Lanska determined that meningoencephalitis could develop with any type of anthrax; however, it is most prevalent in cases of cutaneous anthrax because the majority of anthrax cases are cutaneous.

Treatment was reported in 39 patients, of which 19 received penicillin only, 19 received penicillin in combination with other antibiotics, and one received antianthrax serum only. Dr. Lanska believes it is “important to treat anthrax meningoencephalitis with a polydrug antibiotic regimen” and that “ampicillin or penicillin G alone are not recommended for initial therapy.” Despite aggressive treatment, 75% of the patients died within 24 hours of presentation, and only four patients survived. Of these four patients, three had contracted cutaneous anthrax. In general, surviving patients were younger than those who died, and their cerebral spinal fluid was either normal or less severely abnormal compared to the deceased patients. Although “there is limited information on long-term outcomes among the survivors,” most have reportedly fully recovered.

NR

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