Diabetic non ketotic hyperosmolar state: a special care in aged patients

Summary perosmolar hyperglycemic nonketotic state (HHNS) is an acute metabolic complication occurring characteristically in elderly type-2 diabetic patients. It may account for 10 up to 47 % of cases of severe hyperglycemia with or without ketoacidosis. Many factors associated with advanced age may explain the predilection of both elderly subjects in general and older diabetics in particular to develop hyperosmolar coma, including reduced glomerular filtration rate and elevated renal threshold for glucose (which fall to correct hyperglycemia by osmotic diuresis) , lack of thirst appropriate to the state of hydratation and some iatrogenic factors. In HHNS the age of the patients is the best known prognostic indicator. The increased mortality rate in the elderly diabetics depends on the severity of precipitating acute diseases (gastrointestinal hemorrhage, cardiovascular accident, pneumonia, pancreatitis, etc.), but the frequent compromises of the hemodynamic state and renal function of aged subjects substantially contributes. However, the role of erroneous management is not negligible and difficulties may be encountered in conciliating correction of metabolic disorder with treatment of precipitating illness. Insulin, water and electrolytes are the most important therapeutical tools for the treatment of hyperglycemic emergencies. In HHNS, the aggressive fluid replacement with isotonic or hypotonic NaCl solutions have first priority. Such a type of strategy is difficult to perform in patients suffering from cerebral stroke (which needs of anti-edema therapy) or congestive heart failure (necessitating to avoid fluid excess). According to the literary data, in our experience these two precipitating factors are frequent causes of death. We outline the validity of prefixed protocols of management; on the other hand, we think that the pathophysiological understanding of HHNS in the single patient is essential to decide the proper corrections and to permit a successful outcome. The primary way aiming at diminishing mortality by HHNS is its prevention; it is fundamental to warrant an appropriate fluid intake and to utilize with caution some drugs (thiazides, steroids, phenytoin, etc.) in aged diabetics, especially when nephropathic or unable, or living in nursing homes.