Clinical Briefs

Chronic Hyponatremic Encephalopathy

Most chronic hyponatremia occurs in postmenopausal women, either as a result of thiazide treatment or as a syndrome of inappropriate secretion of antidiuretic hormone. The best therapy for women with hyponatremia is controversial, with some sources suggesting intravenous sodium chloride treatment, and others suggesting fluid restriction. This study evaluated 53 consecutive postmenopausal women with symptomatic chronic hyponatremia, defined as a serum sodium less than 130 mmol/L accompanied by CNS manifestations.

Patients were divided into three groups. In group I, treatment consisted of IV saline prior to the onset of respiratory insufficiency; group two received IV saline after the onset of respiratory insufficient, and group 3 received only fluid restriction.

At 24 hours, the mean plasma sodium in the IV NACL groups (= 125) was substantially greater than that of fluid restriction recipients (= 112). Group 1 required a mean time to correction of 35 hours, and group 2 of 41 hours; but in group 3 (fluid restriction), 10 patients died within the first day. The mean cerebral performance category, a 5-point scale ranging from normal function or only slight disability to persistent vegetative state and death, showed clear benefits of early IV saline: the average cerebral performance category score was 1 for early IV saline, 3.0 for IV saline after onset of respiratory insufficiency, and 4.6 for fluid restriction. No patient who received early IV saline suffered brain damage after up to one year of follow-up, in contrast to patients who received delayed IV saline or fluid restriction. Ayuis and associates conclude that early administration of IV saline is preferred treatment for symptomatic chronic hyponatremia in postmenopausal women, and includes substantial preservation of life and cerebral function.

Ayuis JC, Arieff AA. JAMA 1999;281: 2299-2304.

Incidental Findings on Brain MRI

In a variety of investigational protocols used at the NIH, MRI databases from normal, healthy individuals are required for comparison. This report analyzed brain MRI scans from 1000 healthy volunteers during the May 1996—June 1997 time period. Findings were categorized as: 1) no referral needed or commonly seen in asymptomatic persons (e.g., sinusitis); 2) nonurgent referral needed; 3) urgent referral needed (within weeks); and 4) immediate referral required (e.g., subdural hematoma).

Eighty-two percent of brain MRIs were normal. No finding among these studies required immediate referral. Indeed, more than 90% of the abnormalities found were category 1, with only about 10% requiring any referral and about 7% requiring urgent referral.

Findings included within the routine referral category included (partial listing) old lacunar infarct, pineal cyst, and empty sella; In the urgent category were seen arachnoid cyst, cavernous angioma, astrocytoma, and suspected aneurysm. More than 13% of the study participants manifest sinusitis. Katzman and colleagues note the discovery of several unsuspected CNS neoplasms in persons who, even after repeat thorough scrutiny manifest no related symptoms, may herald additional diagnostic yield and opportunity for early intervention as MRI studies are more widely used.

Katzman GL, et al. JAMA 1999;282: 36-39.

Systemic Glucocorticoids on Exacerbations of COPD

Steroid therapy is commonly administered to patients with COPD at times of exacerbation, especially when exacerbation is sufficient to warrant hospitalization. Despite this practice being routinely applied, there is scant literature to support its efficacy either on immediate or long-term clinical end points. The current study (n = 271) evaluated the difference between treatment of COPD exacerbations requiring hospitalization with and without steroids. Outcomes assessed included first treatment failure, defined as death from any cause, need for intubation or mechanical ventilation, need for readmission due to COPD, or requirement for greater levels of pharmacologic therapy (e.g., adding theophylline, high-dose inhaled glucocorticoids, adding open-label systemic steroids). Also evaluated were changes in FEV-1, length of hospital stay, and death from any cause over a six-month follow-up period.

At admission, steroid was administered as IV methylprednisolone 125 mg q6h ´ 72 hours, followed by either a two-week or an eight-week progressively tapering course of once-daily prednisone, beginning with 60 mg/d.

Steroids significantly reduced the rate of first failure in the first 90 days of the study. Length of hospital stay was significantly longer in the placebo group, and FEV1 improved more quickly in glucocorticoid recipients. Niewoehner and associates conclude that systemic steroids reduce treatment failure in the 90 days after an exacerbation, and that a two-week regimen is as effective as an eight-week regimen.

Niewoehner DE, et al. N Engl J Med 1999;340:1941-1947.