severe precipitating illness, who may be able to return to therapy with oral hypoglycaemic agents once the acute illness and hyperglycaemic crisis have been treated. DKA has also been increasingly described in obese African Americans with type 2 diabetes, sometimes at diagnosis and sometimes after relatively minor or undiagnosed precipitants in individuals with reasonable baseline control.16 20 Characteristically these individuals return to oral hypoglycaemic therapy or diet control after resolution of the acute episode. Recurrent episodes of DKA account for 15% of cases and are more common in those who are female, socially deprived, and of lower educational status. Psychological problems complicated by eating disorder are associated with deliberate omission or under-dosing with insulin and may contribute to 20% of these recurrent admissions in young type 1 diabetic patients.2
Pathogenesis The primary mechanism for the development of ketoacidosis and HHS is a reduction in the effective levels and/or action of circulating insulin with a concomitant elevation of the counter-regulatory hormones: glucagon, catecholamines, cortisol, and growth hormone (fig 1), due to insulin deficiency per se and intercurrent illness.