Overview

Non-ketotic hyperglycemic coma is a metabolic derangement in which there is an abnormally high serum

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

 glucose level without ketoacidosis

Ketoacidosis

Ketoacidosis is a metabolic state associated with high concentrations of ketone bodies, formed by the breakdown of fatty acids and the deamination of amino acids. The two common ketones produced in humans are acetoacetic acid and β-hydroxybutyrate....

. It can occur as a complication of diabetes mellitus type 2 (known or unknown). In 30–40% of cases, it is the patient's initial presentation of diabetes. It also occurs in pancreatic disorders that interfere with the production of insulin, and in conditions marked by an excess of steroids, as in steroid

Steroid

A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

 therapy or acute stress conditions (such as infection, stroke, etc.).
Hyperosmolality, resulting from the extremely high concentration of sugar in the blood, causes a shift of water from the intracellular fluid (the less concentrated solution) into the blood (the higher concentrated solution). This results in cellular dehydration. Another symptom of HHNK, 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...

, occurs because the high plasma osmolality prevents the normal osmotic return of water to the blood by the renal tubules osmotic diuresis

Osmotic diuresis

Osmotic diuresis is increased urination caused by the presence of certain substances in the small tubes of the kidneys. The excretion occurs when substances such as glucose enter the kidney tubules and cannot be reabsorbed...

, and it is excreted in the urine. This leads to a decreased blood volume, which severely hampers the kidney's excretion of glucose and a vicious cycle is begun.

The difference between diabetic ketoacidosis (DKA) and non-ketotic hyperglycemic coma is the fact that in non-ketotic hyperglycemic coma, the body still continues to release enough 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....

to not enter a state of starvation. In DKA, the body cannot use the sugar in the blood, and must begin to metabolize fat and muscle tissue for sustainance, producing acids and ketones as byproducts. In non-ketotic hyperglycemic coma, the pH of the blood is not affected to the same degree as with a patient in DKA.