Dangers of hypoglycaemia unawareness

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 unawareness because such patient may not experience the typical warning symptoms such as tremor and palpitations when their blood glucose decline. These group of medications are known as beta blockers (inclusive of propranolol, atenolol, carvedilol etc)

Hypoglycaemia unawareness may be triggered by:

*A recent history of frequent low blood sugar

* A rapid drop in blood sugar

* Having diabetes for many years

* Stress or depression

* Situation where self-care is a low priority.

* Alcohol consumption in last 12 hours – as alcohol exaggerates hypoglycaemia

* A previous low blood sugar in the last 24-48 hours

* Use of blood pressure medications (beta blockers)

Treatment of hypoglycaemia

Whenever hypoglycaemia occurs, the goal is to immediately supply a source of glucose to raise the blood glucose level, This can usually be done within minutes by ingestion of about 15-20g of carbohydrate, which can be inform of 3-4 ounces of juice, a slice of bread, snacks, glucose tablets or glucose gels, once the person is able to take glucose sources by mouth, the ingestion of oral glucose is a quick way to bring up the blood sugar levels.

If the patient cannot help him or herself, and cannot receive oral glucose, the medical or emergency team can establish a venous access to deliver glucose water directly into the blood and within minutes the patient recovers.

The use of glucagon, a hormone that rapidly counters the metabolic effects of insulin in the liver, causing release of glucose into the blood, it can raise the glucose level by 30-100mg/dl within minutes. This is given as an injection in the emergency rescue kit to treat hypoglycaemia. This ideally must be given by trained persons or personnel and the patient closely monitored.

The best approach to treating hypoglycaemia is to prevent it, and be educated about the symptoms, and most importantly be enlightened on how to deal with it when it occurs; the patients, the caregivers, peers, school teachers, co-workers and the patient families must be educated on what to do when hypoglycaemia occurs.

People who have hypoglycaemia unawareness have a much greater risk of severe hypoglycaemia, up to six-fold, with its attendant morbidity. Hypoglycaemia unawareness may result in many serious forms of morbidity including seizure, coma, fractures and joint dislocation and cardiac arrhythmias, and is occasionally fatal.

Severe episodes of hypoglycaemia or hypoglycaemia unawareness requiring the assistance of another have been shown to be associated with an increased risk of mortality.

The prevention and management of hypoglycaemia unawareness can be complex, and can be achieved by a multi-factorial intervention of clinical care and structured patient education by the diabetes team. Once a diabetic patient is experiencing this medical condition, it is suggested that appropriate action be taken by consulting with your physician so that a management plan can be commenced.

Contact Dr Maxwell on 363-1807 or 757-5411.