Paradoxical glucose infusion for hypernatraemia in diabetic hyperglycaemic hyperosmolar syndrome

Hypernatremia in Hyperglycemia: Clinical Features and Relationship to Fractional Changes in Body Water and Monovalent Cations during Its Development

In hyperglycemia, the serum sodium concentration ([Na]S) receives influences from (a) the fluid exit from the intracellular compartment and thirst, which cause [Na]S decreases; (b) osmotic diuresis with sums of the urinary sodium plus potassium concentration lower than the baseline euglycemic [Na]S, which results in a [Na]S increase; and (c), in some cases, gains or losses of fluid, sodium, and potassium through the gastrointestinal tract, the respiratory tract, and the skin. Hyperglycemic patients with hypernatremia have large deficits of body water and usually hypovolemia and develop severe clinical manifestations and significant mortality. To assist with the correction of both the severe dehydration and the hypovolemia, we developed formulas computing the fractional losses of the body water and monovalent cations in hyperglycemia. The formulas estimate varying losses between patients with the same serum glucose concentration ([Glu]S) and [Na]S but with different sums of monovalent cation concentrations in the lost fluids. Among subjects with the same [Glu]S and [Na]S, those with higher monovalent cation concentrations in the fluids lost have higher fractional losses of body water. The sum of the monovalent cation concentrations in the lost fluids should be considered when computing the volume and composition of the fluid replacement for hyperglycemic syndromes.

Case Report : Severe Hypernatremia following treatment for Hyperosmolar Hyperglycaemic State : A pragmatic approach used to manage hypernatremia

The Hyperosmolar Hyperglycaemia State (HHS) is an endocrine emergency with a mortality rate between 10 and 50%. The mainstay for the treatment of this condition is vigorous IV fluid replacement with close monitoring of blood glucose, serum osmolality, and electrolytes. However, after initial resuscitation, patients can develop hypernatremia and raised serum osmolality, which have deleterious consequences. While hypernatremia in HHS can be treated with infusions of 0.45% saline or 5% dextrose, alternate measures such as intravenous (IV) hypotonic fluid infusion [e.g. 0.18% sodium chloride (NaCl) containing 4% dextrose and 0.15% potassium chloride (KCl)], or free water administration through a nasogastric (NG) tube can be used. We report the case of a 70-year-old man, who was initially admitted to a medical high care ward (MHC) with HHS, and was transferred to the ICU 72 hours later with an altered level of consciousness and severe hypernatremia. His treatment consisted in an IV hypotonic 0.18% NaCl infusion containing 4% dextrose and 0.15% KCl. He also received free water through a NG tube at a rate that was calculated to correct natremia at an average rate of 0.55 meq L-1 hr-1 over 72 hours. A multipronged approach was instituted to manage this patient, including, in addition to natremia correction, blood glucose control with insulin, appropriate IV antibiotics to treat infected foot ulcers, adequate analgesic medications, low-molecular-weight- heparin (LMWH) for thromboprophylaxis, proton- pump inhibitors, and continuation of patient’s ongoing antidepressant drugs at the time of his Glasgow Coma Score improvement. This case report demonstrates the feasibility and success of IV hypotonic fluid (0.18% NaCl - 4% dextrose - 0.15% KCl), alongside NG free water for correcting sodium levels with lower fluid volumes than would have been otherwise required if corrected with 0.45% saline. This treatment seems to be a reasonable choice for correcting sodium levels and osmolality in HHS patients who present with hypernatremia after an initial resuscitation, insofar as it avoids fluid overload and provides dextrose as an energy substrate, in addition to potassium ions. However, while correcting natremia with hypotonic fluid, other aspects of management should not be ignored.

The Corrected Serum Sodium Concentration in Hyperglycemic Crises: Computation and Clinical Applications

In hyperglycemia, hypertonicity results from solute (glucose) gain and loss of water in excess of sodium plus potassium through osmotic diuresis. Patients with stage 5 chronic kidney disease (CKD) and hyperglycemia have minimal or no osmotic diuresis; patients with preserved renal function and diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS) have often large osmotic diuresis. Hypertonicity from glucose gain is reversed with normalization of serum glucose ([Glu]); hypertonicity due to osmotic diuresis requires infusion of hypotonic solutions. Prediction of the serum sodium after [Glu] normalization (the corrected [Na]) estimates the part of hypertonicity caused by osmotic diuresis. Theoretical methods calculating the corrected [Na] and clinical reports allowing its calculation were reviewed. Corrected [Na] was computed separately in reports of DKA, HHS and hyperglycemia in CKD stage 5. The theoretical prediction of [Na] increase by 1.6 mmol/L per 5.6 mmol/L decrease in [Glu] in most clinical settings, except in extreme hyperglycemia or profound hypervolemia, was supported by studies of hyperglycemia in CKD stage 5 treated only with insulin. Mean corrected [Na] was 139.0 mmol/L in 772 hyperglycemic episodes in CKD stage 5 patients. In patients with preserved renal function, mean corrected [Na] was within the eunatremic range (141.1 mmol/L) in 7,812 DKA cases, and in the range of severe hypernatremia (160.8 mmol/L) in 755 cases of HHS. However, in DKA corrected [Na] was in the hypernatremic range in several reports and rose during treatment with adverse neurological consequences in other reports. The corrected [Na], computed as [Na] increase by 1.6 mmol/L per 5.6 mmol/L decrease in [Glu], provides a reasonable estimate of the degree of hypertonicity due to losses of hypotonic fluids through osmotic diuresis at presentation of DKH or HHS and should guide the tonicity of replacement solutions. However, the corrected [Na] may change during treatment because of ongoing fluid losses and should be monitored during treatment.

Pediatric diabetic ketoacidosis and hyperglycemic hyperosmolar state

Diabetic ketoacidosis is an important complication of diabetes in children and is the most frequent diabetes-related cause of death in childhood. The pathophysiology of this condition can be viewed as an exaggeration of the normal physiologic mechanisms responsible for maintaining an adequate fuel supply to the brain and other tissues during periods of fasting and physiologic stress. The optimal therapy has been a subject of controversy, particularly because the most frequent serious complication of diabetic ketoacidosis-cerebral edema-and the relationship of this complication to treatment are incompletely understood. In this article, the author reviews the pathophysiology of diabetic ketoacidosis and its complications and presents an evidence-based approach to the management of this condition.