Diabetic ketoacidosis (DKA) is a complication of diabetes that can occur if the body starts to run out of insulin (the hormone that regulates blood sugar).

It can be caused by a number of underlying problems including an infection, a missed insulin injection or undiagnosed diabetes (see below). In some cases, it may also be triggered by another illness, such as a stroke or a heart attack.

Insulin deficiency

A lack of insulin can send the body’s metabolism into a destructive downward spiral. The metabolism is the complex process of chemical reactions the body uses to break down food into energy.

Insulin enables the body to use blood sugar (glucose). If there is a lack of insulin, or if it can’t be used properly, the body will break down fat instead.

The breakdown of fat releases acidic chemicals (ketones). High levels of glucose and ketones make you pass large amounts of urine. This can lead to severe dehydration.

Therefore, there are a number of interlinked problems with the body’s metabolism that can quickly make a person very ill. These are:

• high blood glucose levels (hyperglycaemia) due to the lack of insulin
• high levels of acid in the blood due to a build-up of ketones
• falling levels of the mineral, potassium, which is essential to good health – vomiting and treatment for diabetic ketoacidosis can cause a decrease in potassium levels (hypokalemia)

Common triggers

The three most common triggers for diabetic ketoacidosis are:

• an underlying infection
• missed insulin treatment
• the onset of previously undiagnosed diabetes (usually type 1 diabetes)

These are discussed in more detail below.

Infection

The body’s response to infection is to produce more glucose. Too much glucose can make insulin treatment ineffective, triggering diabetic ketoacidosis.

The most common infections are:

• urinary tract infection (UTI) – including bladder and kidney infections
• pneumonia – a lung infection
• gastroenteritis – an infection of the digestive system
• flu (influenza)

Missed treatment

There are a number of reasons why someone with diabetes may miss their recommended treatment including:

• psychological stress – often a common cause in teenagers with type 1 diabetes
• frequent injections disrupting daily activity
• finding frequent injections painful
• concern about weight gain 

Undiagnosed diabetes

The symptoms of type 1 diabetes often develop quickly, and a delay in diagnosing the condition can sometimes progress to diabetic ketoacidosis.

However, this only occurs in a small number of people with type 1 diabetes which suggests they have a particularly severe form of the condition compared to other people.

Other triggers

Less common triggers for diabetic ketoacidosis include:

• using illegal drugs, such as cocaine, ecstasy and ketamine
• binge drinking – drinking lots of alcohol over a short period of time or drinking to get drunk
• other illnesses, such as a stroke or heart attack
• a damaged or malfunctioning insulin injector or pump

With prompt treatment, complications of diabetic ketoacidosis (DKA) are uncommon.

However, when complications do occur they are usually serious. The complications of diabetic ketoacidosis are described below.

Cerebral oedema

Swelling of the brain is a very serious complication of diabetic ketoacidosis. It’s caused when excess water builds up inside the brain. The medical term for this is cerebral oedema.

Cerebral oedema is usually seen in children and it occurs in around 1 in every 150 cases of diabetic ketoacidosis. It’s not known why water builds up in the brain in this way.

Symptoms of cerebral oedema include:

• headache   
• drowsiness
• restlessness and irritability
• seizure (fits)

Cerebral oedema is very serious and can cause severe brain damage. In around 1 in 4 cases this can be fatal.

A person with cerebral oedema will be admitted to an intensive care unit (ICU) and treated with a medication called mannitol, which helps reduce the brain swelling.

Acute kidney failure

Severe dehydration can cause your kidneys to stop working (acute kidney failure).

Your kidneys remove waste products from your blood, so if they stop working you may experience a range of symptoms such as:

• swelling in your arms and legs due to a build-up of fluid (oedema) 
• feeling sick
• feeling very tired
• confusion

Until your dehydration has been successfully treated, you may need dialysis. This is a treatment that uses a machine to filter waste products from your blood.

Once your fluid levels have been restored to normal, your kidneys should start to recover.

Adult respiratory distress syndrome

The rapid and unpredictable changes in fluid levels that can occur in diabetic ketoacidosis can occasionally result in the lungs becoming filled with fluid. This is known as adult respiratory distress syndrome and can cause serious breathing difficulties.

If you develop adult respiratory distress syndrome, a machine called a ventilator can be used to help you breathe until your condition stabilises.

Diabetic ketoacidosis (DKA) is a dangerous complication of diabetes caused by a lack of insulin in the body.

Diabetic ketoacidosis occurs when the body is unable to use blood sugar (glucose) because there isn’t enough insulin. Instead, it breaks down fat as an alternative source of fuel. This causes a build-up of a by-product called ketones.

Most cases of diabetic ketoacidosis occur in people with type 1 diabetes, although it can also be a complication of type 2 diabetes.

Symptoms of diabetic ketoacidosis include:

• passing large amounts of urine
• feeling very thirsty
• vomiting
• abdominal pain

Seek immediate medical assistance if you have any of these symptoms and your blood sugar levels are high.

Read more about the symptoms of diabetic ketoacidosis.

Who is affected by diabetic ketoacidosis?

Diabetic ketoacidosis is a relatively common complication in people with diabetes, particularly children and younger adults who have type 1 diabetes.

Younger children under four years of age are thought to be most at risk.

In about 1 in 4 cases, diabetic ketoacidosis develops in people who were previously unaware they had type 1 diabetes.

Diabetic ketoacidosis accounts for around half of all diabetes-related hospital admissions in people with type 1 diabetes.

Diabetic ketoacidosis triggers

These include:

• infections and other illnesses 
• not keeping up with recommended insulin injections
• drug misuse or alcohol misuse

Read more about potential causes of diabetic ketoacidosis.

Diagnosing diabetic ketoacidosis

This is a relatively straightforward process.

Blood tests can be used to check your glucose levels and any chemical imbalances, such as low levels of potassium. Urine tests can be used to estimate the number of ketones in your body.

Blood and urine tests can also be used to check for an underlying infection, which could be a trigger.

After diabetic ketoacidosis has been diagnosed, you’ll probably need regular blood and urine tests to check how well you’re responding to treatment.

Treating diabetic ketoacidosis

If the condition is diagnosed very early, it may be possible to relieve the symptoms with an insulin injection.

People with more advanced diabetic ketoacidosis will need to be admitted to hospital where they will be given a combination of insulin and fluids.

Read more about treating diabetic ketoacidosis. 

Preventing diabetic ketoacidosis 

If you have type 1 diabetes, it’s important you follow your recommended treatment plan, both in terms of taking regular insulin injections as directed and monitoring your blood glucose levels, particularly if you feel unwell.

Read more about preventing diabetic ketoacidosis.

Complications of diabetic ketoacidosis

Diabetic ketoacidosis is potentially very serious. High levels of ketones in the blood disrupt normal working of many parts of the body. The more ketones in the blood, the more ill a person with diabetic ketoacidosis will become.

Left untreated, diabetic ketoacidosis can cause potentially fatal complications, such as severe dehydration, coma and swelling of the brain.

Read more about the complications of diabetic ketoacidosis.

If you’ve been diagnosed with diabetes, it’s very important that you follow all recommendations regarding diet, medication, insulin therapy and self-testing.

Read more about living with diabetes.

During illnesses

An underlying illness (usually an infection) is the most common reason why people with type 1 diabetes develop diabetic ketoacidosis (DKA). It’s therefore important to take extra precautions if you fall ill.

You can use the advice below as a guide.

• Always seek prompt medical advice if you fall ill.
• Remember that some cough mixtures and cold remedies contain sugar. Always use the sugar-free variety.
• If eating normally is difficult, try soups or liquid carbohydrates which are available from many health and fitness stores.
• Drink plenty of sugar-free liquids. Seek immediate medical advice if you’re unable to hold down soups or liquids.
• Continue with your insulin treatment even if you’re unable to eat your usual amounts of food.

It’s likely you will have to increase your insulin injections when you are ill. You should have received previous instructions about this, known as your ‘sick day rules’. Contact your GP or diabetic nurse for advice if you haven’t received these instructions.

You will also need to check your blood glucose levels more frequently (usually at least four times a day).

Ketone testing

A simple urine test, using strips available on prescription, can test for ketones. You should test your urine for ketones if you have a high blood sugar level or if you have the symptoms of ketoacidosis.

Many newer blood glucose monitors are also able to monitor blood ketone levels. Your diabetic nurse will be able to provide you with more information about this.

Contact your GP or diabetes nurse immediately, or go to your nearest accident and emergency (A&E) department, if you have a blood sugar level and the test strips indicate that you also have high levels of ketones.

The initial symptoms of diabetic ketoacidosis (DKA) develop when the body detects that ketones are being produced.

High blood glucose and ketone levels make you pass large amounts of urine. This will make you very thirsty and can lead to dehydration.

Ketones are acidic so as more are produced, the level of acid in your blood will rise. The combination of dehydration and high blood acid levels can trigger a range of additional symptoms such as:

• feeling sick (nausea)
• abdominal pain
• loss of appetite
• shortness of breath

Left untreated, more advanced symptoms will develop such as:

• rapid heartbeat (tachycardia)
• rapid breathing, where you breathe in more oxygen than your body actually needs (hyperventilation)
• being sick, which can make dehydration even worse
• low blood pressure (hypotension), which can make you feel dizzy and lightheaded
• a noticeable smell of ketones on your breath, which is often described as smelling like pear drops or nail varnish remover (not everyone is able to smell ketones) 
• mental confusion
• unconsciousness (coma)

When to seek medical advice

If you think you’re experiencing the initial symptoms of diabetic ketoacidosis, and self-testing shows high levels of ketones in your blood or urine, you should immediately contact your GP or diabetes nurse for advice.

If this is not possible, call your local out-of-hours service or NHS 111 for advice.

If you, or someone in your care, appears to be experiencing more advanced symptoms of diabetic ketoacidosis, go immediately to your nearest accident and emergency (A&E) department.

Diabetic ketoacidosis (DKA) is usually treated in hospital.

Depending on how advanced your symptoms are you may be admitted to a standard ward, a high dependency ward or an intensive care unit (ICU).

Diabetic ketoacidosis is treated using a combination of:

• insulin (usually pumped into a vein) 
• fluids pumped directly into a vein to rehydrate your body 
• replacement of minerals, such as potassium, which may have been lost through vomiting and other treatment of diabetic ketoacidosis 

If someone with diabetic ketoacidosis is unconscious, a feeding tube can be used to remove stomach contents and stop them breathing in vomit. Urine can be drained out of the bladder using a thin tube called a catheter.

As long as there are no complications, you should be able to leave hospital when you are well enough to eat and drink normally and tests show no, or few, ketones left in your body.

Before or shortly after being discharged from hospital, your diabetes nurse will discuss why you had an episode of diabetic ketoacidosis so a plan can be put in place to prevent future episodes.

For example, if diabetic ketoacidosis was caused by an illness, you’ll need a ‘sick day plan’ so you can adjust your insulin dosage accordingly.

If diabetic ketoacidosis occurred as a result of missing an insulin treatment, you’ll need to discuss the reasons for this and whether there’s anything that can be done to make insulin therapy more convenient.