[The refeeding-syndrome in older patients]

The refeeding-syndrome is a potentially life-threatening metabolic complication that may occur after the initiation of a nutritional therapy in malnourished patients. The syndrome is not well known and probably frequently unrecognized and untreated. The pathophysiology is characterized by a progressive depletion in potassium, sodium and phosphate, despite mostly normal serum levels. This occult intracellular depletion is aggravated by the reintroduction of energy intake and thus compensated by a rapid transcellular shift from the extra- to the intracellular space. At that stage, suddenly decreasing serum levels occur and are responsible for the respective symptoms. Malnutrition, weight loss, chemotherapy, diuretics and alcoholism are the most important risk factors. Accordingly, due to the high prevalence of malnutrition in older persons, the refeeding-syndrome frequently occurs in this patient group. However, prevalence data are scarce. About 8 % of older hospitalized patients develop the refeeding syndrome if a nutritional therapy is introduced. The symptoms of the refeeding syndrome are various and unspecific. In geriatric patients, it frequently occurs in the form of a delirium. Particularly specific is the time course. The refeeding-syndrome typically develops within a few days after the start of a nutritional therapy. If serum-electrolytes, including magnesium and phosphate are monitored and supplemented tightly, the syndrome can be prevented or treated at an early stage. In addition, the measurement and supplementation of thiamine and the particularly slow increase of energy intake are fundamental for the prevention and treatment of the syndrome.