Diabetic ketoacidosis in paediatrics: tools to assist in recognition of a sick child

Background

Diabetes is a disorder of carbohydrate, protein and fat metabolism resulting from a lack of insulin or a reduction in its biological effects.

Type 1 diabetes is a result of an autoimmune process that causes the destruction of insulin-secreting β cells in the pancreas. It is divided into two types: type 1A immune-mediated diabetes; and type 1B, idiopathic diabetes.

In type 1A, which makes up 90–95% of cases, the rate of β cell destruction varies, so it is rapid in some individuals, mainly infants and children, and slower in others, which is why children often have diabetic ketoacidosis (DKA) as their first presentation.

The deconstruction of β cells and absolute lack of insulin in type 1 diabetes means these individuals are prone to the development of DKA. This is because one of the main actions of insulin is the inhibition of lipolysis and release of free fatty acids from fat cells. When insulin is absent, ketosis develops when these fatty acids are released from fat cells and is converted into ketones in the liver.

Type 1A is an autoimmune disorder thought to be the result of genetic preposition or an environmental trigger event, such as infection and hypersensitivity mediated by T lymphocytes. In type 1B, there is β cell destruction with no evidence of autoimmunity (Porth, 2015). Both these processes begin many years before of symptoms appear and clinical detection.

Often known as non-insulin-dependent diabetes, type 2 diabetes is more common, with around 90% of people with diabetes having type 2. These patients are usually older at onset and have minimal symptoms. Recently, there has been a rise in the cases of type 2 diabetes in obese children, which is linked to socioeconomic factors such as income and social status. Within type 2, three main metabolic abnormalities are involved: insulin resistance; increased glucose production by the liver; and impaired secretion of insulin by the pancreatic β cells. Its pathophysiology is shown in Figure 1.

DKA is the first presentation of childhood diabetes in around 30–40% of cases and is more common in younger children (Harding, 2019), with infections being the most common precipitating factor for it (Turan et al, 2020).

DKA occurs when there is a relative or absolute lack of circulating insulin within the body, so cells cannot take glucose from the blood. This insulin deficiency forces cells to provide energy for metabolism from other sources such as fat cells, so the body metabolises triglycerides and amino acids instead of glucose for energy. The rise in ketone levels is caused when glucagon stimulates mitochondrial conversion of the free fatty acids; this process is normally blocked by insulin (Brutsaert, 2020). This process produces acidosis and ketones; the movement of potassium into cells causes the body to go into hypokalaemia.

DKA in children is commonly missed or incorrectly diagnosed; this is primarily because of varying presentations such as vomiting and abdominal pain (Helman, 2015). Other factors affecting diagnosis include communication; a young child or a one with learning difficulties might not be able to express their symptoms, which can make differential diagnosis more difficult.

Although type 1 and 2 are the most common causes of diabetes, diabetes can also be caused by factors such as medication, for example in children who use corticosteroids regularly for conditions such as asthma and other respiratory disorders.

Conditions such as cystic fibrosis can cause pancreatic insufficiency and Down's syndrome, which is caused by trisomy, can also affect insulin production.

Around 96% of children with diabetes have type 1 diabetes which is caused by the destruction of pancreatic β cells by an autoimmune process (Lissauer and Carroll, 2018). Although thought to be a disease that progresses quickly, it develops over a long period. Progressive immunological damage leads to the deconstruction of pancreatic β-cells. After 80% of the pancreatic β-cells have been destroyed, symptoms start to develop as insulin demand increases (Hackett et al, 2013).

Genetic and environmental factors are associated with type 1 diabetes; for example, a child has a 6–9% chance of developing the condition if their father has insulin-dependent diabetes and 2–4% if their mother does. Certain viruses can trigger the process of destruction within islet cells, causing diabetes. In children, the most common viruses are a group called enteroviruses, which are single-stranded, positive-sense RNA viruses; these viruses are responsible for illnesses such as hand-foot-and-mouth disease, myocarditis and aseptic meningitis (Lamb, 2019).

There is an important difference between DKA and hyperosmolar hyperglycaemic state (HHS). HHS differs in that, unlike DKA, there is a more severe degree of dehydration because of osmotic diuresis and the absence of ketosis. These patients have a lower concentration of free fatty acids and glucagon (Karslioglu French et al, 2019).

Recognition

DKA is one of the leading causes of childhood mortality (Harding, 2019). Although not the most common paediatric illness to present prehospitally, DKA is an emergency and can lead to death if left untreated.

The priority when managing DKA is early treatment and reversing its effects as soon as possible. This is usually possible only in a hospital, and early recognition and transportation to hospital by paramedics ensures the best possible outcome.

DKA is present with a blood sugar of ≥11 in children, but can present in paediatric patients with a relatively normal blood sugar (Joint Royal Colleges Ambulance Liaison Committee (JRCALC), 2019).

Table 1 shows the common signs and symptoms and Table 2 shows pertinent issue when taking a history when assessing for DKA.

Children with DKA commonly present with tachycardia, tachypnoea and a fever which in children can be often lead to a diagnosis of pneumonia or more common respiratory conditions. Within the UK, respiratory conditions account for 66% of paediatric presentations to emergency departments, 25% of which are via ambulance (Lissauer and Carroll, 2018).

Other symptoms of DKA include polyuria, which is apparent because of dehydration in relation to the body's hyperosmolarity as a response to hyperglycaemia. Breath smelling of ‘pear drops’ can be a common symptom within DKA; this is caused during ketosis when the liver releases acetone as a by-product and the smell is on the breath when the body is expelling the acetone.

The most common cause of mortality from DKA is cerebral oedema, which causes 25% of deaths in paediatrics; this is thought to be caused by rapid dehydration and hypoperfusion in children (Wolfsdorf et al, 2018).

Assessment tools

A number of tools and guidelines can be adapted into practice for assessing children prehospitally. Although these tools are beneficial, they are not always appropriate and should not replace hands-on skills but be used alongside existing knowledge.

The phrase ‘children are just small adults’ could not be further from the truth; children differ a great deal regarding the illnesses they experience, how developed their immunity is and how conditions present (JRCALC, 2019).

One of the first tools to be implemented prehospitally was the paediatric assessment triangle (Horeczko, 2011); this is an internationally accepted tool for the initial emergency assessment of infants and children. This tool has three components: appearance; work of breathing; and circulation to skin. Each area of the tool is used to assess key components quickly and recognise a sick child needing immediate interventions.

This tool helps practitioners to recognise categories of illness such as respiratory distress, shock, respiratory failure, central nervous system and metabolic disorder or cardiopulmonary failure. It is important to note that this tool does not recognise respiratory distress and shock.

This tool allows a rapid assessment to be carried out using only visual and auditory clues, although assessment should be continue throughout the care of the patient to monitor for any potential deterioration.

Although this tool is beneficial especially prehospitally when assisting clinicians and aiding their diagnosis, it should be kept in mind that as infants develop into children and young adults, certain areas of the triangle should be adapted. For example, red flag markers for infants in the work of breathing area include signs such as tracheal tug, head bobbing and intercostal recession (Horeczko, 2011) but in children and young adults, these areas are less appropriate because the anatomy has changed so signs and symptoms change. Clinicians should adapt the characteristics of the triangle depending on the age of the patient. This tool is recognised as a key global assessment tool (Horeczko, 2011).

The next tool is known as the paediatric early warning score (PEWS). Initially designed to monitor patients in hospital, it has been adapted and exists in a variety of forms. The tool is based on a scoring and a traffic light system to identify variation in patients and possible deterioration.

One adaptation of the PEWS is the Paediatric Observation Priority Score (POPS) (Roland et al, 2014). This takes into consideration the clinician's initial overall impression. One recent study looked at how the implementation of a paediatric early warning system prehospitally, in this case POPS, would develop clinician's confidence in recognising a sick child (Snelson, 2019). This small cohort study found that ambulance clinicians reported higher levels of confidence and competence after they had used the POPS or PEWS tool to aid recognition of a sick child (Snelson, 2002).

The tool's scoring chart is adapted for children of various ages. Clinicians should use POPs as a prompt for questions such as ‘How unwell is this child?’ and ‘Is this patient time critical?’ POPS should not be used as the answer but should aim to aid recognition, and recognises that the impression of the professional matters. If a practitioner feels the child looks extremely unwell but the scoring is low or vice versa, they should act upon their initial overall impression. In this situation, it is important to consider that using tools such as PEWS or POPS might mean a possible misdiagnosis; they score against SpO₂ and respiratory rate but do not include blood glucose or ketones which aid in recognition of DKA.

For example, this tool might identify possible markers for sepsis but clinicians should remember the first question of sepsis should be: ‘Is there a source of infection?’ If this is unlikely, they should consider a differential diagnosis.

PEWS was designed for the recognitionof deterioration and continuous monitoring of patients, unlike POPS, which is aimed at identifying the urgency of the child's need for medical attention (Snelson, 2019).

All tools should be used alongside the collection of basic observations such as blood pressure, oxygen saturations, heart rate, respiratory rate, blood sugar and temperature. These observations create a well-rounded picture of the clinical presentation of patients. However, blood sugar in children is usually checked only if clinically indicated, not routinely.

Research shows that DKA is commonly misdiagnosed as the signs and symptoms in children can vary (Helman, 2015). This evidence shows that unless this is not possible—for example, because it would cause significant distress—clinicians should check blood sugar as standard practice to aid a well-rounded, holistic approach to care and management. Point of care testing devices have the potential to enhance clinical decision making, accelerate time to treatment and reduce inappropriate conveyance (Heaney, 2020).

The importance of history-taking, especially in children, should be understood by any professional. History-taking concerns the presenting complaint as well as an informative history. This should be approached in a structured manner, as this helps practitioners to remember all the areas that need to be covered within the history (Sambrook, 2019).

This process is also about introducing yourself to the family and the patient, and making them feel comfortable. At this point, clinicians should adapt their communication to meet the needs of the patient. For example, when dealing with infants and young children, it might be an idea to come down to their level, allow them to keep playing or be with a parent so they feel comfortable.

Different skills can be implemented such as using a playful approach to assessment and questions, or including toys or props to help the child understand what might be happening. Using a teddy to show them a clinical assessment or demonstrating this process on their parent can help children feel settled. It is important to remember questions should be addressed to the child, where appropriate, as well as to the parents or guardians.

When asking questions about past medical history, professionals should remember to include questions around when the mother's pregnancy: was it full term? Were there any complications? Practitioners should also ask if the child is up to date with vaccinations. These questions are important if clinicians are to understand any factors that might be contributing towards the complaint.

Management

Relating to the presentation of DKA in paediatrics as per JRCALC (2019) and British Society for Paediatric Endocrinology and Diabetes (2020) guidelines for children presenting with DKA, unless there clearly is circulatory failure, intravenous fluids are not advised and, if they are administered, this should be done so slowly so as not to cause cerebral oedema. Signs of cerebral oedema include confusion or irritability, bradycardia and decreased SpO₂ (Harding, 2019).

Prehospitally, paramedics administer little treatment for DKA; it is usually a case of transferring the patient to the nearest emergency department. It is more beneficial if the clinician looked at cases holistically and took the time to understand and educate. They should take the time to ask questions about the child's diet and exercise, as this information could prove paramount for the specialists at the hospital.

It is important for clinicians to understand that many guidelines emphasise the importance of recognising DKA; JRCALC guidelines (2019) identify that while fluid therapy is beneficial, this should not be prioritised over transportation to hospital unless there is an immediate concern or life-threatening risk to a patient who appears shocked or is in circulatory failure.

These guidelines also discuss the importance of identifying ketones as soon as possible; this is not always possible in the prehospital setting as the equipment needed is often not available. This is where knowledge and an understanding key signs and symptoms of DKA in paediatrics play a large role in aiding future management and ensuring that quick treatment being received as soon as possible (JRCALC, 2019)

Conclusion

While the main focus when managing DKA is early treatment and reversing its effects as soon as possible, this is often only possible in a hospital.

When applying research and clinical guidance to the best management of these patients prehospitally, paramedics should have a solid foundation of knowledge of DKA and its common presentation in children.

Prehospitally, early recognition and early transportation to hospital of these patients ensures the best possible treatment is given.

The underpinning knowledge of DKA allows professionals to aid in diagnosis and also means that signs and symptoms can be used to identify a presenting cause without relying on observations such as blood glucose, which can remain at a normal level, or ketones.

Key points

CPD Reflection Questions