Diabetic ketoacidosis (DKA): warning signs, ketone levels and hospital treatment

Insulin is the hormone that lets sugar (glucose) move from the blood into the body's cells, where it is used for energy. Diabetes UK explains that without enough insulin the body cannot do this, so it starts breaking down fat instead. This releases harmful chemicals called ketones. When ketones build up they make the blood acidic, and a large build-up can make someone seriously ill very quickly.

The NHS puts it simply: DKA is where a lack of insulin causes ketones to build up in the blood. It is a medical emergency rather than a condition that can be managed at home once it is established, which is why recognising the early signs and acting on them matters so much.

DKA is different from hypoglycaemia (low blood sugar). Diabetes UK points out that people sometimes call both a "diabetic attack", but they are opposite problems with different treatment, so a blood glucose check is an important first step whenever someone with diabetes becomes unwell.

The NHS says DKA usually affects people with type 1 diabetes, but it can also happen in people with type 2 diabetes who need insulin. Diabetes UK says it is more likely in someone with type 1 diabetes, in anyone who uses insulin, and in people taking SGLT2 inhibitors, and that it can occasionally affect people on tablets or people who have not been diagnosed.

DKA can also be the way type 1 diabetes is first found. Both the NHS and Diabetes UK note that this is particularly the case in children, who may become very unwell before the diagnosis has been made. This is why the classic early signs of type 1 diabetes in a child (going to the toilet a lot, being very thirsty, being tired and losing weight) deserve a prompt same-day check.

Diabetes UK also notes that people with type 2 diabetes who become very unwell with high blood sugar may develop a related emergency called hyperosmolar hyperglycaemic state (HHS) instead of DKA. The NHS states that HHS is rare in type 2 diabetes, can build up over a few weeks and is usually caused by an infection and dehydration. Both conditions can be life threatening.

The NHS lists the symptoms of DKA as feeling thirsty, needing to pee more often, stomach pain, feeling or being sick, diarrhoea, breathing more deeply than usual, breath that smells fruity (like pear drop sweets or nail polish remover), tiredness, sleepiness or confusion, and blurred vision. NHS inform lists deep breathing, abdominal pain and nausea and vomiting together with the usual signs of high blood sugar.

Diabetes UK lists the common triggers in people who already have diabetes. Some people have no obvious trigger, which it acknowledges can be worrying and confusing.

• Being ill, for example with a chest infection, flu or urinary tract infection.

• High blood sugar caused by a growth spurt or puberty.

• Not taking insulin or missing doses.

• An insulin pump not working properly or becoming dislodged.

• Surgery or an injury.

• Having a heart attack or a stroke.

• High blood sugar caused by having a period.

If you have diabetes and any symptoms of DKA, the NHS advises checking your blood glucose first. If it is high, test for ketones if you can. Diabetes UK says that if blood sugar is high (usually above 13) or you feel very unwell you should check ketones, and that a blood ketone test shows levels in real time while a urine test shows what they were a few hours ago.

The NHS and NHS inform give the same guide for blood ketone meters. These levels are a guide only. The NHS stresses that normal levels can differ from person to person, so your diabetes care team's own advice takes priority.

The NHS says to call 999 or go to A&E if you have a high level of ketones (over 3mmol/L in blood, or over 2+ in urine), if you do not know your ketone levels but have symptoms such as thirst, needing to pee often, sleepiness or confusion and fruity breath, or if you have symptoms of DKA and have not been diagnosed with diabetes. NHS inform adds that someone who becomes unconscious needs a 999 call.

The NHS also advises not driving yourself to A&E. Ask someone to drive you or call 999 for an ambulance, and bring the medicines you take.

Urgent advice from your diabetes care team or NHS 111 is recommended by the NHS if your blood glucose is high and insulin is not bringing it down (even with normal ketones), if your ketones are slightly high (0.6 to 1.5mmol/L) and you feel unwell, or if your ketones are 1.6 to 3mmol/L even when you feel well.

Diabetes UK says DKA is diagnosed in hospital with a blood test. NICE Clinical Knowledge Summaries tells clinicians to suspect it in a person with known diabetes, features of diabetes or significant hyperglycaemia plus signs such as nausea or vomiting, abdominal pain, fast or deep sighing breathing, dehydration, or reduced consciousness.

NICE CKS adds an important point: hyperglycaemia may not always be present, and people on insulin can develop DKA with normal blood glucose levels, so ketones should be tested for in a person with suspected DKA even if glucose is near normal. In children and young people, blood ketones are tested, and if that is not possible, immediate hospital admission is arranged.

NICE CKS also lists other things that can sit behind an episode, including infection such as gastroenteritis, physiological stress such as trauma or surgery, not taking insulin as prescribed (including deliberately leaving out insulin to lose weight), disordered eating or other mental health conditions, other conditions such as hypothyroidism or acute pancreatitis, and some drugs or alcohol and drug misuse. This is a good reason for the hospital team to ask openly about what led up to the episode.

The NHS says anyone with DKA is admitted to hospital for urgent treatment. You are given insulin, fluids and nutrients through a drip into a vein, and you are monitored for complications, because DKA can sometimes affect the brain, heart or lungs. Diabetes UK also mentions monitoring for problems with the kidneys.

Diabetes UK explains that the early signs of DKA can sometimes be treated with extra insulin and fluids if picked up quickly, but if not it needs urgent hospital care. People can go home once their ketones are at a safe level and they can eat and drink normally; NHS inform adds that they should also be able to take insulin.

Before discharge the doctors and nurses talk about what caused the episode and how to reduce the chance of it recurring, which often includes reviewing sick day rules, insulin doses, ketone testing and equipment such as a pump.

The NHS says causes of DKA can include being unwell, having an injury or surgery, having your period or not taking enough insulin, and that testing for ketones helps you know when to take action such as increasing your insulin dose. Kit to test ketones is available free from the NHS if advised by your care team, or it can be bought from a pharmacy.

• Follow the treatment plan agreed with your diabetes care team, including adjusting your insulin dose when you need to.

• Check blood glucose regularly, and ask the care team about a continuous or flash glucose monitor if you do not have one.

• Test for ketones when your blood glucose is high and when you are ill.

• Follow the sick day rules you have been given. Diabetes UK says these usually include drinking more sugar-free fluids, taking more insulin and checking blood sugar more often than usual.

• Do not stop taking insulin, even if you are not eating, and do not skip doses (NHS).

• Contact your care team if you are not sure what to do.

DKA is treated as an emergency through 999, A&E and the hospital admission pathway, so there is no meaningful private-versus-NHS choice at the moment of crisis. Ongoing diabetes care in the NHS is delivered by a diabetes care team, usually including a diabetes nurse and a specialist team, and NICE CKS notes that people with type 1 diabetes should be offered a diabetes education programme and support with sick day rules.

Some people also choose a private diabetes consultation for routine review. The clinical principles of ketone testing and early action are the same wherever you are seen, and any emergency should still go to the nearest A&E.