Diabetic ketoacidosis (DKA): a metabolic derangement in type 1 diabetes that results from a deficiency of insulin. Highly acidic ketone bodies are formed, resulting in acidosis; usually requires hospitalization for treatment and is usually caused by nonadherence to the insulin regimen, concurrent illness, or infection.
Hyperglycemic hyperosmolar nonketotic syndrome (HHNS): a metabolic disorder of type 2 diabetes resulting from a relative insulin deficiency initiated by an intercurrent illness that raises the demand for insulin; associated with polyuria and severe dehydration.
Comparison of DKA Vs HHNS:
DKA is caused by an absence or markedly inadequate amount of insulin. This deficit in available insulin results in disorders in the metabolism of carbohydrate, protein, and fat. The three main clinical features of DKA are:
• Dehydration and electrolyte loss
DKA Pathophysiology vs HHNS Pathophysiology:
HYPERGLYCEMIC HYPEROSMOLAR NONKETOTIC SYNDROME (HHNS):
HHNS is a serious condition in which hyperosmolarity and hyperglycemia predominate, with alterations of the sensorium (sense of awareness). At the same time, ketosis is minimal or absent. The basic biochemical defect is lack of effective insulin (ie, insulin resistance). The patient’s persistent hyperglycemia causes osmotic diuresis, resulting in losses of water and electrolytes.
To maintain osmotic equilibrium, water shifts from the intracellular fluid space to the extracellular fluid space. With glucosuria and dehydration, hypernatremia and increased osmolarity occur.
This condition occurs most often in older people (ages 50 to 70) with no known history of diabetes or with mild type 2 diabetes. HHNS can be traced to a precipitating event such as an acute illness (eg, pneumonia or stroke), medications that exacerbate hyperglycemia (thiazides), or treatments, such as dialysis.
The history includes days to weeks of polyuria with adequate fluid intake. What distinguishes HHNS from DKA is that ketosis and acidosis do not occur in HHNS partly because of differences in insulin levels. In DKA no insulin is present, and this promotes the breakdown of stored glucose, protein, and fat, which leads to the production of ketone bodies and ketoacidosis.
DKA is a Type I hyperglycemic crisis associated with metabolic acidosis and elevated serum ketones, and HHNS is aType II hyperglycemic crisis with the absence of ketone formation.