Nonketotic hyperosmolar coma (nonketotic hyperglycaemia) is a type of diabetic coma

Diabetic coma

Diabetic coma is a reversible form of coma found in people with diabetes mellitus. It is a medical emergency.Three different types of diabetic coma are identified:#Severe diabetic hypoglycemia...

 associated with a high mortality seen in diabetes mellitus type 2

Diabetes mellitus type 2

Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...

. The preferred term used by the American Diabetes Association

American Diabetes Association

The American Diabetes Association is a United States-based association working to fight the consequences of diabetes, and to help those affected by diabetes...

 is hyperosmolar nonketotic state (HNS). Other commonly used names are hyperosmolar hyperglycemic nonketotic coma (HHNKC) or hyperosmotic non-ketotic coma (HONKC). It is also called Hyperglycemic Hyperosmolar State (HHS), as some patients may have some ketonuria and it does not necessarily cause coma.

Pathophysiology

Nonketotic coma is usually precipitated by an infection, myocardial infarction, stroke or another acute illness. A relative insulin deficiency leads to a serum glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

 that is usually higher than 33 mmol/l (600 mg/dl), and a resulting serum osmolarity that is greater than 350 mOsm. This leads to polyuria

Polyuria

Polyuria is a condition usually defined as excessive or abnormally large production or passage of urine . Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom...

  (excessive urination, an osmotic diuresis), which, in turn, leads to volume depletion and hemoconcentration that causes a further increase in blood glucose level. Ketosis

Ketosis

Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...

 is absent because the presence of some insulin

Insulin

Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

 inhibits lipolysis

Lipolysis

Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into free fatty acids followed by further degradation into acetyl units by beta oxidation. The process produces Ketones, which are found in large quantities in ketosis, a metabolic state that occurs when the liver...

.

Clinical presentation

The increasing hemoconcentration and volume depletion may result in:

• Hyperviscosity and increased risk of thrombosis
  Thrombosis
  Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...
  
  .
• Disordered mental functioning.
• Neurologic signs including focal signs such as sensory or motor impairments or focal seizures or motor abnormalities, including flaccidity, depressed reflexes, tremors or fasciculations.
• Ultimately, if untreated, will lead to death.

Intravenous fluids

Treatment of HHS begins with reestablishing tissue perfusion using intravenous fluids. People with HHS can be dehydrated by 8 to 12 l. Attempts to correct this usually take place over 24 hrs with initial rates of normal saline often in the range of 1 l/hr for the first few hours.

Electrolyte replacement

Severe potassium deficits often occur in HHS. They usually range around 350 mEq in a 70 kg person. This is generally replaced at a rate 10 mEq per hour as long as there is urinary output.

Insulin

Insulin is given to reduce blood glucose concentration; however, as it also causes the movement of potassium into cells, serum potassium levels must be sufficiently high or dangerous hypokalemia

Hypokalemia

Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...

may result. Once potassium levels have been verified to be greater than 3.3 mEq/l, then an insulin infusion of 0.1 units/kg is begun.