Hyperglycemic hyperosmolar syndrome in children: pathophysiological considerations and suggested guidelines for treatment.

A.H. received support from the Alberta Diabetes Institute and the Women & Children’s Health Research Institute at University of Alberta. These Clinical Practice Guideline are endorsed by the Lawson Wilkins Pediatric Endocrine Society. They were developed to be of assistance to endocrinologists by providing guidance and yperglycemic hyperosmolar syndrome (HHS), characterized by extreme elevations in serum glucose concentrations andhyperosmolalitywithout significant ketosis, has historically been infrequent in children. However, recent case reports and series describing HHS in children suggests that the incidence of this disorder may be increasing. The epidemiology of HHS in children and adolescents has been reviewed recently. HHS has a high mortality rate, and an understanding of the unique pathophysiology (Figure 1) of this condition is important to guide clinical decision-making. However, although treatment of diabetic ketoacidosis (DKA) in children is familiar to most clinicians, the management of HHS in youth presents a unique set of clinical challenges for which little guidance is currently available. The aim of this review is to discuss the pathophysiology of HHS and to provide broad treatment recommendations on the basis of the available literature and known physiological principles. Criteria for the diagnosis of HHS are listed in Table I. Although HHS is distinct from DKA (Table II; available at www.jpeds.com), patients may present with features of both conditions. HHS occurs less frequently in children than DKA, and some children with DKA can have severe hyperosmolality, complicating the recognition of HHS as a distinct entity. As a result, children with HHS are often treated with DKA protocols. However, the pathophysiology of HHS differs from DKA, and these differences should be considered in planning a rational therapeutic approach. Unlike the usual symptoms of DKA (hyperventilation, vomiting, and abdominal pain), which typically bring children to medical attention, the gradually increasing polyuria and polydipsia of HHS may go unrecognized. As a result, both dehydration and electrolyte loss are profound in HHS; in adults, fluid losses in HHS have been estimated to be twice those of DKA. Furthermore, obesity and hyperosmolality can make the clinical assessment of dehydration unreliable. It has been suggested on the basis of information from small case series that intake of copious quantities of carbonated sugar-enriched drinks before presentation may be a common feature of patients presenting with severe hyperglycemia. Because these case series lack control data, however, it is unclear whether this finding is specific to these patients.