New onset diabetes after transplant

New onset diabetes after transplant (NODAT) affects between three and 13 per cent of children and young people who have an organ transplant. The medicines needed to prevent the body rejecting the organ can also affect insulin production and uptake.

Insulin is a hormone which controls the concentration of glucose (sugar) in the blood. Insulin is released by beta-cells in the pancreas. Normally, the beta-cells release insulin in response to the concentration of glucose in the blood. Glucose is the body’s energy source, and the insulin transports the glucose into the cells where it is needed.

When there is a high concentration of blood glucose, the beta-cells release more insulin to allow the glucose to be absorbed from the blood. If there is a low concentration of glucose, the beta-cells release a much smaller amount of insulin or even switch off insulin production.

This keeps the blood glucose concentration balanced and at the right concentration for the rest of the body to function normally.

The medicines needed to prevent the body rejecting the transplanted organ – immunosuppressant medicines – also affect how insulin is produced and how the body reacts to it. We currently use a combination of immunosuppressants. The most common include prednisolone, tacrolimus, azathioprine, and mycophenolate mofetil (MMF). Each type affects the body in different ways.

The liver reduces the amount of glucose it releases in response to insulin. Steroids make the liver less sensitive to insulin, so it carries on releasing glucose even if the pancreas is releasing insulin. Steroids also stop glucose being absorbed by muscle and fat in the body, so it circulates in the blood stream. Steroids reduce the body’s sensitivity to insulin and therefore more insulin is required to transport the glucose into the cells.

The pancreatic beta-cells release insulin in response to the amount of glucose in the blood. If the blood glucose is high more insulin is released to bring them down to a normal range. Calcineurin inhibitors prevent beta-cells from making insulin efficiently and so the blood glucose may remain high and therefore lead to a diagnosis of diabetes.

The signs and symptoms of NODAT are the same as for other types of diabetes. These can include:

• dry mouth
• thirst
• increased urination (peeing)
• feeling tired
• weight loss

Some people can have high blood glucose concentration without showing any symptoms. This is why it is important to have regular blood tests to measure the concentration of glucose in the blood.

NODAT is diagnosed with a finger prick test for a small sample of blood to look at the blood glucose concentration and this will be checked by a specialist team as an inpatient or outpatient. If a child or young person has a fasting blood glucose above 7 mmol/L or a random blood glucose above 11.1 mmol/L, they have diabetes.

NODAT is treated with insulin injections. The child will need to check their blood glucose concentration regularly and adjust their insulin dose if needed. Our clinical nurse specialist for diabetes will teach the parents and the child how to manage their diabetes.

Treatment aims to keep blood glucose levels between 4 and 10 mmol/l.

Insulin is used to aim to keep blood glucose levels in the ideal target range between 4 and 10 mmol/L by helping glucose leave the blood and enter the cells where it can be used for energy. The dose of insulin given can be adjusted according to the amount of carbohydrate eaten.

There are three main food groups: carbohydrate, protein and fat.

Carbohydrate is a term for both starch and sugar (glucose) and it is the only food group that directly affects blood glucose levels.

Fat and protein have very little effect on blood glucose levels.

Carbohydrate foods are digested and absorbed into the blood at different rates. Sugary foods will be broken down into glucose and absorbed quickly and so cause blood glucose levels to rise quickly.

Examples of sugary foods:

• non-diet fizzy drinks
• honey
• syrup

Starchy carbohydrates are absorbed much more slowly and so do not have an immediate effect on blood glucose levels. Examples of starchy foods:

• rice
• pasta
• chapatti
• potato
• bread
• breakfast cereals

Carbohydrate is also found in fruit and in milk and milk products like yoghurt.

The child may have to adjust their diet as well to help manage their blood glucose concentration. We will arrange for the child to see a diabetes specialist dietitian to understand how best to manage diet and diabetes.

The specialist team monitoring the child’s transplant will also be involved as adjusting the dose and/or type of immunosuppressant medicines may improve blood glucose concentration.

It is important to eat regular meals and snacks, including starchy carbohydrates, protein and fat. This will ensure we get enough energy and nutrients to maintain a healthy body weight.

People should avoid any drinks that contain sugar such as fizzy drinks and squashes. You should also avoid sugary sweets. Fruit juice contains a lot of fruit sugar so should only be taken in small quantities with a meal.

Milk and milkshakes are a good source of energy (calories) and calcium. It is okay to continue to include these as part of your diet. All sugar-free drinks are suitable.

It is important that people continue to eat plenty of starchy carbohydrate foods as part of their meals. These foods are a good energy source and provide important nutrients. Try to include them at each meal.

If people currently have food or drink between meals, then they should continue to do so.

If you are taking insulin to manage diabetes then a hypo is a blood glucose level of less than 4.0 mmol/L. If you are NOT taking insulin to manage diabetes and are only adjusting diet, then a hypo is a blood glucose level of less than 3.0 mmol/L. Symptoms of hypo include dizziness, feeling shaky, sweaty or hungry or looking pale. Hypo should be treated with 15 grams fast acting carbohydrate. (You may need less than 15 grams dependant on the age/ size of child or young person).

Some examples are in the table below:

Once treated, wait 15 minutes and then the blood glucose level should be re-checked. If it is still less than 4.0 mmol/l then re-treat.

If blood glucose has increased have 15-20 grams of slow-acting carbohydrate to prevent levels from dropping again.

The child will have regular blood tests as part of their long term follow up after transplant, both to monitor blood glucose concentration and the levels of immunosuppressant in the body. The doctor will discuss with the parents whether there are alternative medicines their child could take to manage their condition.