Hyperosmolar syndrome or diabetic hyperosmolar syndrome is a medical emergency caused by a very high blood glucose level.
The prefix "hyper" means high, and "osmolarity" is a measure of the concentration of active particles in a solution, so the name of the syndrome simply refers to the high concentration of glucose in the blood.
Hyperosmolar syndrome may take a long duration - days and weeks - to develop. However, certain signs and symptoms may indicate that such a condition is developing. Some of the signs include the following[1]: