Diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS) are life-threatening complications of diabetes. UK and USA guidelines for treating diabetic emergencies have some important differences and further research is needed to define the best approach.
Diabetes is a common and important medical condition in which the body either cannot produce or becomes insensitive to the hormone insulin. There are two main types of diabetes – Type 1 in which the body’s own immune system attacks the pancreas cells which make insulin, and Type 2 in which body cells become insensitive to insulin, or the pancreas is unable to produce sufficient amounts.
Insulin allows body cells to absorb glucose from the circulation, providing them with the energy source they need to function. In people who have diabetes, blood glucose levels rise because glucose is not absorbed into cells – this is called “hyperglycemia”. If left untreated, in the long-term, hyperglycemia can cause damage to the blood vessels and affect organs such as the kidneys and eyes. In the short term, diabetic hyperglycemia may lead to the development of serious chemical imbalances in the body.
In type 1 diabetes, since the body is unable to use glucose for energy it begins to use fat as an alternative energy source. This can cause a buildup of toxic acidic byproducts called ketones, which can quickly lead to the development of a condition called diabetic ketoacidosis (DKA). DKA is a life-threatening imbalance in the body’s chemical environment and must be treated urgently. Some people may develop DKA before they are aware that they have type 1 diabetes. Other patients may develop DKA if their insulin treatment is insufficient or becomes unbalanced, due to missed insulin treatment, increased exercise or an infection. Symptoms of DKA include: thirst, excessive urination, abdominal pain, nausea & vomiting, rapid breathing, “fruity” smelling breath (from the ketones) and confusion. Patients need to recognize the symptoms of DKA so they can seek urgent medical help.
DKA is usually a complication of Type 1 diabetes, but it can also develop in Type 2 diabetes. If Type 2 diabetes is not well controlled, patients can develop another hyperglycemic condition called “hyperglycemic hyperosmolar state” (HHS). In HHS there are very high blood glucose levels and high osmolarity (or concentration) of the blood – but no ketones or acidosis. HHS develops over days to weeks, rather than rapidly as with DKA. Patients are commonly adults or elderly. Symptoms of HHS include: thirst, excessive urination, severe dehydration, warm dry skin, abdominal pain, nausea & vomiting and confusion. Like DKA, HHS is life-threatening and must be treated urgently.
The main principles of treating patients with DKA or HHS are similar. These are: rehydration with intravenous fluids, insulin treatment to reduce hyperglycemia, and rebalancing the chemical environment by giving the necessary electrolytes. However, there have been few large studies to determine the best approach. This has led to some differences in patient management in the USA and UK. In addition, the different healthcare provision systems in the two countries have had an impact on treatment. In the UK there is universal health coverage, whereas the USA has a mostly health-insurance system. In the USA, it has been important to consider safe affordable treatments for those who have minimal insurance coverage. In a recent review article in Current Diabetes Reports, researchers from the UK and the USA compared the recommended guidelines in each country.
Diagnosis and treatment of DKA
In both countries, three factors must be present in order to diagnose DKA: “D” – diabetes (measured by blood glucose levels), “K” – ketones (measured in the blood or urine), “A” – acidosis (measured by blood pH and serum bicarbonate). However, there are two main differences in the diagnostic criteria.
- In the USA, DKA is subdivided into “mild”, “moderate” or “severe”, based on the level of acidosis and the mental state of the patient. This determines how patients are treated.
- In the UK, the blood glucose level required for diagnosis of DKA is lower. This recognizes that some diabetic patients with ketoacidosis may not have very high glucose levels (referred to as “euglycemic ketoacidosis”).
Both the UK and USA agree on the principles of treatment for DKA. The fluid replacement and insulin infusion recommendations are similar, although there are some differences in how the insulin infusion rates should be adjusted as treatment progresses. However, in the USA, the diagnostic grading of DKA into mild, moderate and severe is linked to different treatment programs. Patients diagnosed as having mild DKA can be treated in a less intensive environment, which is still safe but more affordable. This protocol reflects that healthcare delivery in the USA is provided by a health insurance system, and healthcare cost is an important consideration.
Diagnosis and treatment of HHS
The diagnosis of HHS is not as well defined as DKA. The main distinguishing feature of HHS is lack of ketones and acidosis – no (or low) ketones in the blood and urine and the serum pH level and bicarbonate levels do not show acidosis. The blood glucose levels in HHS are higher than those seen in DKA. Because HHS develops over a long period, patients are severely dehydrated and blood osmolarity (concentration) is elevated.
Whilst the UK has separate guidelines for diagnosis and management, the US has combined guidelines for both DKA and HHS. Blood osmolarity is calculated in different ways in the US and UK, and patients diagnosed with the USA criteria are likely to be more dehydrated before receiving treatment. It is unclear if this leads to a difference in outcomes.
As with DKA, treatment of HHS involves correction of dehydration and hyperosmolarity by giving fluids, lowering hyperglycemia by giving insulin and correcting the body’s chemical environment by giving electrolytes. The differences in the UK and US treatment guidelines are mostly related to choice of fluid and timing of insulin initiation. Both sets of guidelines agree that serum osmolarity must be closely monitored during treatment, as correcting this too quickly can lead to complications.
The UK and USA guidelines for the diagnosis and treatment of DKA and HHS are similar but there are some important differences. This is because of the lack of any large studies to determine the best approach. It is also partly related the different healthcare provision systems in the two countries. It is hoped that further research in both the UK and USA will improve management of these serious diabetic emergencies.
Written By: Julie McShane, Medical Writer