"Low-dose" versus "high-dose" insulin regimens in the management of uncontrolled diabetes. A survey

Cerebral edema in diabetic ketoacidosis

OBJECTIVE

To review the causes of cerebral edema in diabetic ketoacidosis (CEDKA), including pathophysiology, risk factors, and proposed mechanisms, to review the diagnosis, treatment, and prognosis of CEDKA and the treatment of diabetic ketoacidosis as it pertains to prevention of cerebral edema.

DATA SOURCE

A MEDLINE search using OVID was done through 2006 using the search terms cerebral edema and diabetic ketoacidosis. RESULTS OF SEARCH: There were 191 citations identified, of which 150 were used. An additional 42 references listed in publications thus identified were also reviewed, and two book chapters were used.

STUDY SELECTION

The citations were reviewed by the author. All citations identified were used except 25 in foreign languages and 16 that were duplicates or had inappropriate titles and/or subject matter. Of the 194 references, there were 21 preclinical and 40 clinical studies, 35 reviews, 15 editorials, 43 case reports, 29 letters, three abstracts, six commentaries, and two book chapters.

DATA SYNTHESIS

The data are summarized in discussion.

CONCLUSIONS

The causes and mechanisms of CEDKA are unknown. CEDKA may be due as much to individual biological variance as to severity of underlying metabolic derangement of the child's state and/or treatment risk factors. Treatment recommendations for CEDKA and diabetic ketoacidosis are made taking into consideration possible mechanisms and risk factors but are intended as general guidelines only in view of the absence of conclusive evidence.

Diabetic Ketoacidosis: Pathophysiology, Management and Complications

Diabetic ketoacidosis (DKA) is a common and potentially life-threatening complication of diabetes mellitus, the second most common chronic childhood disease [1]. Prior to the introduction of insulin to clinical medicine by Banting and Best in 1922, DKA had a mortality rate greater than 60% [2]. As insulin was introduced into clinical practice, there was a gradual decrease in mortality associated with DKA over the subsequent 30 years. Recent epidemiological data reveal current mortality varies from 0 to 19% [3,4]. DKA continues to be the most common cause of death in patients younger than 24 years of age; it accounts for as many as 50% of deaths of young diabetic patients [5–7]. In elderly diabetics who have coexisting diseases, DKA carries a high mortality [8]. Despite many advances in the care of diabetic patients, the prevalence of DKA is not declining; it accounts for 14% of all diabetes-related hospital admissions [3, 4, 9].

The incidence of insulin-dependent diabetes mellitus continues to increase worldwide and has roughly doubled in each recent decade [10–13]. Because insulin-dependent diabetes mellitus is increasing, and preventative measures to avoid DKA in diabetic patients have not been successful, the incidence of DKA can also be expected to increase in coming years. Prevention of DKA is the ultimate goal (80% of hospital admissions for DKA occur in treated diabetics) [3,8]. It is necessary for clinicians to understand the pathophysiology and treatment of DKA to care for this increasing diabetic population. We discuss the pathophysiology of diabetic ketoacidosis, its management, and its complications.

Diabetic ketoacidosis. Biochemistry, physiology, treatment, and prevention

Diabetic ketoacidosis (DKA) is the most common cause of death of juvenile-onset diabetics, and as such represents an important issue for pediatricians. In this article, the author reviews the endocrinology of insulin and the glucose counter-regulatory hormones, which are the basis for the development of DKA. The effects of hyperglycemia and acidosis upon organ physiology are detailed, and this serves as the foundation for subsequent discussion of the management of the patient with DKA. Finally, the author summarizes current strategies for prevention of DKA in patients with diabetes.

Insulin infusion for diabetic children

Low-dose insulin infusion was used successfully in the management of 10 diabetic children aged 3.5 to 16.7 years (five ketoacidosis, four with insulin refractory hyperglycaemia, and one during elective surgery). The mean duration of infusion was 33 hours, with a mean infusion rate of 2.9 units/h for the ketotic subjects, and 2.6 units/h for those requiring stabilization. The over-all mean hourly rate per kg body weight was 0.074 units. Extension of the infusion time beyond that needed for the immediate correction of the hyperglycaemia and/or ketoacidosis enabled the smooth transition to a subcutaneous insulin regimen. Low-dose insulin infusion has introduced a new dimension of flexibility in the management of diabetes in the paediatric age group; the technique can be used to break the cycle of insulin-refractoriness as well as to reverse ketoacidosis. The surgeon can also anticipate a more predictable control of blood glucose level during major surgery when a continuous insulin infusion regimen is used.

Diabetic ketoacidosis. Reassessment of therapeutic "truths"

The diagnosis of diabetic ketoacidosis remains, as always, a bedside clinical exercise. Rapid consideration and exclusion of other conditions associated with altered consciousness that may occur in diabetics, such as lactic acidosis, hyperosmolar states, hypoglycemia, alcohol-related ketosis, and infections, should be routine. Although recent reassessment of therapy has meant more rational and specific action, close attention to the physical and laboratory responses to treatment is equally essential for a successful outcome.

Low-dose continuous intravenous insulin infusion in childhood diabetic ketoacidosis

We studied 58 children with diabetic ketoacidosis using a random, prospective protocol, with insulin administered either as a low-dose continuous infusion or as high-dose intermittent subcutaneous injections. There were no statistically significant differences between admission pH and glucose determinations or the time to metabolic correction. The incidence of hypoglycemia and hypokalemia was higher in patients receiving subcutaneous insulin. Insulin levels in the low-dose patients were 85--160 microU/ml. The insulin required to achieve metabolic recovery was 1.6 U/kg in the low-dose group and 4.5 U/kg in the high-dose group (p less than 0.01). Glucose administered at a rate of 3 to 4 g er unit of insulin infused in the low-dose group maintained a serum glucose of 150 to 250 mg/dl. Our studies suggest that low-dose intravenous insulin therapy is safe, as effective as high-dose intermittent subcutaneous injections and avoids the risks of hypoglycemia and hypokalemia. Meticulous attention to individual patient care, however, must remain the most important single variable.