Deficiencies in medical care of hyponatremic patients identified

Reduced plasma sodium concentration (hyponatremia) is the most common electrolyte disturbance, affecting up to 15 % of hospitalized patients. There are many possible causes and the identification of cause is often important for the management of the severely hyponatremic patient. There is some evidence to suggest that this is an area of medicine where optimal clinical care is not always delivered. 

A recent study was designed to assess the quality of the clinical assessment and management of hyponatremia in a large UK teaching hospital. During a six-month period, all 104 patients with a serum sodium of 125 mmol/L or less were identified.

A consultant endocrinologist with a special interest in hyponatremia retrospectively reviewed the case notes of each of these 104 patients. In order to make the required clinical judgments, standards were set by the group. These standards were judged to reflect best practice in three areas: investigation of hyponatremia, criteria for diagnosis of the cause of hyponatremia, and management of hyponatremia. 

For example, all of the following laboratory tests were considered necessary for adequate assessment of the hyponatremic patient: plasma sodium; creatinine and osmolality; urine osmolality and sodium; and assessment of adrenal function, preferably using the short Synacthen test.

The review of case notes revealed inadequacies in all three areas; by the standards set, none of the patients were adequately investigated, a cause for hyponatremia was not established for half of the patients, and serious errors of management occurred in a third of cases. 

The results of the study have persuaded the authors to conclude that investigation and evaluation of hyponatremia is "often inadequate". They also found evidence that treatment of hyponatremia is sometimes "arbitrary and illogical" and may have contributed to the death of some patients.