Hypoglycemia Unawareness 

Our Body  has an inbuilt mechanism to control Blood glucose levels and insulin is instrumental in bringing down the glucose levels- but what if there is'nt enough glucose in the blood- their exists another set of hormones called the glucose counter regulatory hormones which increase the blood glucose levels whenever required. The brain has no reserves of energy and cannot survive even few minutes without suffiecient energy to power the enormous processing which goes on all the time, even when we are asleep. If the blood glucose levels fall below 60 mg/dl the glucose counter regulatory hormones come into action and release reserves of glucose stored in the liver and kidneys.

Glucose counter regulatory hormones 

These Hormones comprise of Glucagon- secreted by the pancreas, Noradrenaline secreted by the adrenal glands, the sympathetic nervous system also becomes active, epinephrine is released from the nerve endings- this stimulates the body to release glucose from body stores, food to be expediently absorbed from intestines, heart beats faster, peripheral blood vessels constrict and skin becomes cold. The central nervous system ( our brain) comes into action and directs us to eat something- we have a craving for food. The signals for all these actions is transmitted by the autonomic nervous system, due to autonomic neuropathy- a diabetic person may not feel any symptoms of hypoglycemia or low blood sugar like extreme hunger, craving for food, palpitations, cold skin and sweating,- Which a normal person would have felt.

Autonomic Neuropathy 

But what if the nerve circuitory fails, blood glucose levels keep falling and the body does'nt take any action to increase the blood glucose levels. This is what happens in Hypoglycemia unawareness, blood glucose levels are critically low, brain may stop functioning leading to coma or epilepsy like seizures but body still does not do anything to mobilize glucose from its stores and pump it into blood. This is one of the fatal complications of longstanding diabetes and is caused when the nerves of the autonomic nervous systems like some branches of the vagus nerve get affected and do not conduct the required signals to heart, intestines stomach liver and pancreas which increase the blood glucose levels.