What must parents know if their child has diabetes? And what should the child at least have heard about? As of now you can find the answers here in the Diabetes-Parents-Journal under the section ‘Education’. Claudia Nestoris MD will be in charge.

People with type 1 diabetes, in which they are unable to produce enough or any insulin, need various kinds of insulin in order to keep up with the body’s various needs. Biochemically produced basal insulin differs from the insulin made naturally by the body in that it is bound to chemical substances. After injection, these particular substances separate themselves from the insulin molecules only after some time, consequently delaying the effect of the insulin. Long and fast-acting insulin analogues, in which the amino acids inside the molecules have been replaced, complete the spectrum of therapeutical possibilities. Insulin is produced by the beta cells in the pancreas, and is the most potent anabolic hormone in the body. It is involved in the building of cells in many different metabolic processes. It assists in the production and storage of carbohydrates, fats and proteins in the bodily cells, and at the same time controls their release into the blood stream.

Insulin the regulator
Insulin regulates the balance between glucose uptake in the intestines, glucose production in the liver, and glucose uptake and breakdown in the other organs.

The liver as glucose source
Readily available energy taken from glucose molecules that circulate in the bloodstream, is stored in the liver cells as glycogen. This metabolic process is known as glucogen synthesis, and has been found to occur in other organs. However, the liver is the only organ that can return the stored energy back to the whole body. The highly specialized liver cells are also able to build glucose from amino acids and other metabolic products (gluconeogenesis). In these ways, the liver plays a key role in the delivery of glucose and energy. In non-diabetic individuals, exactly the right amounts of insulin are constantly released into the bloodstream to deal with the hepatic glucose production, or even to stop it if necessary.

Why insulin concentrations swing so sharply
The insulin concentrations in the blood swing sharply for many reasons. In fasting tests, it has been found that in children, as compared to adults, there is a lower rate of non-prandial basal insulin secretion. In puberty, on the other hand, the rate rises to levels that exceed that of adults. The reason being is that, in puberty, there is an increase in the hormones that act against insulin, such as growth hormones. These particular hormones decrease the level of insulin sensitivity in the cells (insulin resistance).

How much insulin does the body secrete?
Studies have shown that the child’s body has an average non-prandial basal insulin secretion of 0.35 IU/kg (IU= International Units) and a prandial (mealtime) insulin secretion of around 0.65 IU/kg body weight. With a total insulin daily requirement of 1 IU/kg, one can estimate that one-third of the total daily insulin consists of non-prandial basal insulin, that is, that which is needed according to the glucose production of the liver alone. On this physiological basis, an insulin therapy should be developed for those with an absolute shortage of insulin, namely, children with type 1 diabetes. The name of this therapy is intensified conventional therapy (ICT). The idea behind this kind of therapy is to treat separately the long-acting basal insulin, ie, the insulin used to counter the non-prandial hepatic glucose production, and the prandial bolus insulin secretion, ie, the insulin released in response to mealtimes. In this way, diabetics can choose when and how much they want to eat. They can eat large quantities of carbohydrates and cover it well with fast-acting normal insulin or even with the rapid-acting insulin analogues. Internationally recognized studies have repeatedly demonstrated the advantages of ICT, and have proven it to be, without doubt, the best possible form of therapy in terms of achieving good HbA1c values and reducing the incidence of complications.

What kind of insulins are used for ICT?
Basal insulins
For basal insulin therapy, there is the so-called ‘NPH’ (Neutral Protamine Hagedorn) insulin, which has an onset of action of approximately 90 minutes, a peak effect after four to five hours, and a maximum duration of effect of 16 to 22 hours, similar to long-acting insulin analogues. In children, we advocate the administering of NPH insulin several times a day to individually tailor the basal insulin supply, since this allows a reduction in the dosage of insulin, for instance, before and after a strenuous football game.
The long-acting insulin analogue, Detemir, is best used to cover the nocturnal basal insulin requirement in young patients that need extra insulin in the early hours. NPH insulin is often not sufficient to cover this. The incidence of nocturnal hypoglycaemia with Detemir is considerably lower due to its flatter peak of action.
For young people with a very regulated daily routine, the insulin analogue Glargin, with its 24-hour duration of action may be a good option. It only has to be injected once a day, but does not allow for spontaneous dosage alterations.

Prandial (bolus) insulins
The bolus insulins for mealtimes and for corrective measures are the ‘normal’ insulins and fast-acting insulin analogues.
Those who use normal insulin at mealtimes should be aware of its course of action. Its onset of action is 15 to 30 minutes, its peak effect occurs at 2 to 2.5 hours, and its maximum duration of action is 6 to 8 hours. This requires at least one snack after two hours to counter the flood of insulin. Furthermore, one has to adhere carefully to the injection/eat gap of 30 minutes. If the meal is begun too early, the rise in blood sugar at the beginning of the meal will not correlate with onset of action of the insulin.
Fast-acting insulin analogues can also be injected after meals (useful for toddlers in which it is difficult to foresee how much they will eat). However, as a rule, it is recommended to inject directly before meals in order to achieve a good synchronicity between the peak of action (after 30 minutes) and the post-prandial blood sugar surge. The duration of effect of fast-acting insulin analogues is usually complete after two hours. This means that additional injections are necessary for snacks. It is, therefore, not so feasible to use this type of insulin by itself.
A special form of ICT is with the use of an insulin pump. An insulin pump is used exclusively with rapid-acting insulin, whereby small amounts are infused every hour to cover the basal requirements, and all mealtimes and snacks, as well as corrective doses can be individually administered by the press of a button.

Misinterpretations
In daily practice, inadequate metabolic results often lead to an erroneously high settings in the basal insulin. This occurs if the blood sugar, especially between meals, is only sporadically monitored. In this case, the high blood sugar levels measured before the next meal are interpreted as an indication of insufficient basal insulin, although the blood sugar level was probably too high at the time of the last snack when, in fact, it would have been better to increase the dose of bolus insulin before the previous meal.
Also, children often don’t admit to having snacks, which would usually require an additional fast-acting insulin injection. The resulting high blood sugar level is likewise falsely interpreted as an indication of insufficient basal insulin.
Finally, it must be mentioned that if the basal dosage is abnormally high, the constant tendency to hypoglycaemia causes the child to constantly eat, which may lead to a weight problem.
Once the basal dose has been established, it is not to be altered on a day-to-day basis, especially not according to the results of a single blood sugar measurement. If the blood sugar before bed is found to be high, this should not be corrected by raising the basal dosage, but preferably by an extra dose of a fast-acting insulin analogue.

The course of action is dosage-dependent
With bolus insulin, it is important to remember that the effect is, to some extent, dependent on the dosage. For instance, it is well known that the peak of action of normal insulin is between 1.5 and 3 hours with smaller doses (0.05 UE/kg), between two and five hours with average doses (0.2 UE/kg), and between 2.5 and some 7 hours (0.4 UE/kg) with high doses. This actually allows the users total freedom of choice as to how many carbohydrates they want to consume at any particular meal. However, adolescents who consume large amounts of carbohydrates often cannot counter the resulting glucose surge (hyperglycaemia). Conversely, a few hours after the meal, hypoglycaemia can occur.

Is my child injecting the proper amount?
Prior to a session with the paediatric diabetologist, an accurate protocol must be taken. Only by knowing the exact blood sugar values directly before, 90 and 120 minutes after meals, can the dosage of insulin be properly set. Trends that last for more than three days in a row should also be taken into consideration.
The keeping of a protocol is often a nuisance for children—this is why it is a good idea to turn it into a duty for the whole family. The protocol should be taken as a part of life, and not as a means to apply pressure, otherwise the child’s openness and trust—so essential to diabetes management—may be lost.

Author
Claudia Nestoris MD
Kinderkrankenhaus auf der Bult
Hannover
E-Mail: nestoris(at)hka(dot)de