A ten-year-old error in the medical literature continues to cause doctors to improperly treat a potentially life-threatening condition affecting tens of thousands of hospital patients a year, a new study has shown.
The malady, called hyponatremic encephalopathy, involves brain swelling and other symptoms, killing a fourth of all patients who develop it if not treated properly. Its cause is low salt concentrations in the blood, a condition which can be quickly and easily remedied, leading almost always to a full recovery if treated properly, a medical team reports.
This conclusion, based on a study of the treatment received by 53 hospitalized postmenopausal women with the condition, is published in the June 23 issue of the Journal of the American Medical Association (JAMA). The authors are J. Carlos Ayus, MD, professor of medicine at Baylor College of Medicine, and Allen I. Arieff, professor of medicine at the University of California, San Francisco (UCSF).
Their hospital-based study, backed up by a review of all available reports in the medical literature, estimates that the condition is incorrectly treated almost half of the time.
The correct treatment, they report, is the simple procedure of increasing patients' salt concentration intravenously within recommended guidelines, usually only for about two days. But about half of medical professionals nationwide mistakenly believe that such a sodium chloride IV infusion may cause brain damage, they report.
Instead, Ayus and Arieff say, it is withholding salt IV that actually causes the patients to suffer brain seizures. If untreated, this can be followed by respiratory failure and death.
"This belief that the salt IV will lead to brain damage has been in the literature for more than a decade," said UCSF's Arieff. "Our study shows that it is mistaken. Every patient treated with the IV as the paper describes fully recovered, and was fine a year later."
By contrast, all those not given the IV treatment died or were permanently incapacitated, Arieff and Ayus found.
The JAMA issue which carries their report also contains an editorial on the study and its importance for medical treatment, by James Kanochel, MD, professor of medicine at the University of Texas.
The study was based on outcomes of patients treated at hospitals associated with UCSF and Baylor College of Medicine, but the mortality rates among the women with the condition at the two medical centers were almost identical to those from all other patients with this condition reported nationwide, Arieff and Ayus found. This indicates that the study is representative of the situation nationwide, Arieff said.
People suffering from hyponatremic encephalopathy show lower-than- normal blood levels of sodium chloride, along with early symptoms of nerve system damage: headache, nausea, vomiting and weakness, Arieff explained. If salt levels continue to drop, patients can develop swelling of the brain, seizures, respiratory failure and death.
The older literature suggests that treating patients with infusions of salt - even within accepted guidelines -- can cause brain damage. But this is based more on supposition than actual data, Arieff and Ayus conclude.
Interestingly, a number of the women in the study had been hospitalized following brain seizures and hip fractures. Arieff suggests that they may have suffered their seizures precisely because low salt concentrations in the blood had caused brain swelling. Further, he says, their hip fractures may well have been the result of falls following the seizures.
"The importance of hyponatremic encephalopathy both as a cause of seizures and injury at home, as well as a dangerous complication in the hospital should not be underestimated," he says, particularly when such a simple and effective treatment is readily available.
The study was funded by the National Institute of Aging.
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