Hypoglycaemia is a condition characterised by low blood sugar, below which the body and the brain can function.
Hypoglycaemia is the most common and most serious complication of diabetes treatment and especially those on insulin treatment.
Development of symptoms in response to a low blood glucose level provides a fundamental defence for the brain, by alerting the affected individual to the imminent development of neuroglycopenia (low blood glucose supply to the brain) which provokes an appropriate response to reverse the decline in blood glucose levels.
Failure of these warning symptoms to occur or a delay in their occurrence until the blood glucose has fallen to a level which causes disabling neuroglycopenia can have serious consequences.
Hypoglycaemia unawareness is the reduced ability or failure to recognise hypoglycaemia at the physiological blood glucose levels at which warning symptoms normally occur.
The expectation when blood sugar goes below the normal physiological level is that symptoms such as shaking, cold sweating trembling and tremor will set in as a result of the release of stress hormones or counter regulatory hormones such as glucagon, epinephrine (adrenaline), and somatostatin. These hormones triggers processes in the body to warn the body of the low sugar levels and also initiates process in the body that raise blood glucose levels.
Danger of autonomic nerve damage
Diabetes causes nerve damage over time; the longer the duration of the diabetes, the greater the risk of nerve damage. The release of adrenaline is a function of the autonomic nervous system. This function is lost over time. During hypoglycaemia, the body normally release Adrenaline which is responsible for the palpitation, sweating and tremor, giving the patient warning signs. Adrenaline also stimulates the liver to release stored glucose by breaking down glycogen via a process of glycogenolysis and also the production of glucose from non-carbohydrate sources like protein and fats via a process of gluconeogenesis.
In the absence of adrenaline release or reduced levels (due to nerve damage), the patient may not be aware that his/her glucose level is low, as warning signs are not triggered.
Also in the absence of appropriate adrenalin release, the usual response of glucose generation via glycogenolysis and gluconeogenesis may be lost or reduced.
Brain desensitisation
Another reason for hypoglycaemia unawareness may be due to the brain 'getting used' to the low glucose level as a result of frequent or repeated episodes of hypoglycaemia. The brain gets so accustomed to low glucose levels and no longer send signals for adrenaline to be released during such times, hence it does not react until sometime the glucose level gets to dangerously low levels.
Use of certain medications
Certain medications used to treat high blood pressure can blunt the effects of adrenaline and related hormones. If these medicines are used in diabetic patients who have high blood pressure, it may cause hypoglycaemia un
