Hypoglycaemia: A Diabetes Emergency
Published: 23 August 2022
Published: 23 August 2022
Hypoglycaemia is a condition that occurs when a person’s blood glucose level (BGL) drops to a very low level (below 4mmol/L) (Diabetes Australia 2022).
The body’s most important glucose sensors are located in the brain (the brainstem and hypothalamus), with 30% of blood glucose being used to sustain normal brain activity (Amiel 2021).
When the brain is starved of energy, it will start to shut down certain areas that control memory and balance and stimulate hunger. The brain will also release stress hormones. Following treatment of a hypo, it can take 40 minutes to re-establish full brain function.
It’s crucial to treat hypoglycaemia quickly in order to prevent the person’s BGL from continuing to decrease, which can cause them to become seriously unwell (Diabetes Australia 2022).
It’s also important to be aware that not all people with diabetes can experience hypoglycaemia. Those treated with either insulin or sulfonylurea tablets (gliclazide, glimepiride, glipizide, glibenclamide) are at risk of hypoglycaemia. The remaining glucose-lowering medicines do not cause hypoglycaemia.
Hypoglycaemia is a significant contributor to morbidity and mortality. In US hospitals, admission trends between 1999 to 2011 showed a reduction in hyperglycaemia presentations, but an increase in hypoglycaemia (JAMA Network 2014).
English hospital admission data for hypoglycaemia between 2005 and 2014 shows that 72% (72,568 admissions) occurred in people aged 60 years or older, whilst nearly one in five people had more than one admission during this nine year period (Zaccardi et al. 2016).
Hypoglycaemia can be classified into 3 levels:
Glycaemic criteria/description | |
Level 1 | BGL <3.9mmol/L |
Level 2 | BGL <3.0mmol/L |
Level 3 | A severe event characterised by altered mental and/or physical status requiring assistance for treatment. |
(ADA 2021)
The fear and anticipation of hypoglycaemia impacts on the self-management of a person with diabetes, and often prevents them from achieving optimal glycaemic control. Amiel (2021) explains that for people with diabetes, hypoglycaemia may be better defined by the degree of distress and disruption each episode causes, ranging from ingesting carbohydrate when not wishing to do so, to the acute stress response symptoms, and in some cases, confusion and coma.
Hypoglycaemia risk can be divided into key areas for people with diabetes who are prescribed either insulin or a sulfonylurea agent:
(JBDS-IP 2020)
For inpatients with diabetes, hypoglycaemia risks can be significant and may include:
(JBDS-IP 2020)
When people who have diabetes use the same spot to inject insulin, they can develop fibrous and hardened areas. Therefore, the insulin does not get absorbed from that site, causing the patient to increase their dose. If the patient then administers that higher dose of insulin in a non-affected area, they are at risk of a severe hypo, because they are absorbing 100% of that insulin, as opposed to injecting into the affected areas of lipohypertrophy.
Those with impaired renal function, including patients on haemodialysis, will have an increased hypo risk. This is because people need less insulin once they’re on dialysis. Furthermore, as the kidneys (or renal function) deteriorate, they are unable to remove the byproducts of these medicines.
Individuals with chronic kidney disease, heart failure and/or cardiovascular disease have a higher rate of severe hypos than those without comorbidity.
People with type 1 diabetes experience around two episodes of mild hypoglycaemia every week. The annual prevalence of severe hypos in people with type 1 diabetes is close to 30%. Factors such as how long the person has had the condition may increase their risk.
People with type 1 diabetes are highly likely to have a hypo (83%). 40% of those people will experience hypos at night and 15% of these cases will be deemed severe (Frier 2014).
Adults with insulin-treated type 2 diabetes experience a lower frequency of mild and severe hypoglycaemia episodes compared to those with type 1. However, the frequency of those hypos rises progressively the longer they are treated with insulin (Frier 2014).
In people with type 2 diabetes, less than half will experience a hypo over a month. Only 15% will experience them at night, and a much lower number (8%) will experience a severe hypo.
Patients with insulin-treated type 2 diabetes are more likely to require hospital admission for a severe hypoglycaemic episode compared to those with type 1 diabetes (Frier 2014).
Autonomic symptoms | Neuroglycopenic symptoms |
---|---|
|
|
(Tauchmann 2022)
In addition, headache (especially frontal) and nausea can also be experienced.
Treatment of hypoglycaemia will depend on four factors:
It is vital to remember that you are treating low blood glucose, not low blood sugar. According to the American Diabetes Association Standards of Medical Care (2021), hypoglycaemic treatment with pure glucose is the preferred option as it correlates with a quicker response compared to carbohydrate foods.
The first step is to check the blood glucose level. Following this, the treatment is always the same, which is to replace low blood glucose with glucose. Hypoglycaemia treatment is outlined on the National Subcutaneous Insulin Chart and the National Subcutaneous Non-Acute Insulin Chart (ACSQHC 2022).
The ‘Rule of 15’ is used to effectively treat hypoglycaemia. This can be achieved with 15 grams of glucose, which is available in a variety of forms.
Step 1: Preferred treatment: Consume 15 grams of glucose. Examples include:
In the absence of available glucose, consume 15 grams of fast-acting carbohydrate. Examples include:
Wait 15 minutes and then check BGL.
Step 2: If blood glucose level is still 4.0 mmol/L or less, repeat step 1 (or step 2 if glucose is not available) and recheck blood glucose in 15 minutes.
Step 3: If BGL has increased to above 4 mmol/L, consume a nutritious meal to maintain your blood glucose level.
If the next meal is more than an hour away, consume a snack containing 15 grams of longer-acting carbohydrate. Examples of snacks include:
(NDSS 2022; JBDS-IP 2020; Better Health Channel 2021; CDC 2021)
For patients prescribed a thickened fluid/vitamised diet, initial hypoglycaemia treatment requires one tube of oral glucose gel that can be squeezed onto a spoon for ease of use. The use of thickened cordial or adding sugar to vitamised food will delay the initial reversal of hypoglycaemia. If BGL has risen above 4.0mmol/L, the patient should consume a meal or a 15 g snack (if their next meal is more than an hour away) within 15-20 minutes. Ensure the meal or snack is appropriately prepared in line with the patient’s texture modification requirements (Better Health Channel 2021).
For patients on enteral tube feeding, an initial treatment of 15 g glucose powder administered by the tube and flushed with 40 to 50 ml to prevent tube blockage should be administered. If BGL has risen above 4.0 mmol/L, commence the next feed within 15 to 20 minutes.
A cumulative impact of hypoglycaemia exists that can include:
(Amiel 2021)
It’s helpful and useful to acknowledge the fears and concerns people with diabetes have towards hypoglycaemia. Self-management behaviour can change as a result, for example, suboptimal dosing of insulin, overeating and avoiding social situations or sporting activities.
Resources are available through the National Diabetes Services Scheme. Structured hypoglycaemia education programs have been shown to reduce the number and severity of hypo events experienced, help to regain some lost signs and symptoms, and reduce anxiety and distress (Diabetes.co.uk, 2019).
Wearable technology such as continuous glucose monitoring with alarm alerts for low blood glucose levels has significantly reduced the number of hypoglycaemic events by notifying when blood glucose levels reach a specified level.
Smart insulin pumps and hybrid closed-loop systems also reduce the time spent in a hypoglycemic range. With the future development of full closed-loop systems, technology will adapt to the changing demands of insulin for the individual, taking into account meals, exercise, emotions and stress (Mathieu 2021).
The future may include ‘smart’ insulin that is activated/deactivated depending on ambient glucose levels, thus eliminating the risk of hypoglycaemia.
Question 1 of 3
Which of the following is NOT a medical issue that puts you at risk of hypo?