The diagnosis diabetes demands responsibility from children and adolescents right from the start. Parents are sure to feel this too. Diabetes places a mortgage on further disorders affecting especially the thyroid glands, intestines and adrenal glands, making early detection and treatment all the more important.  

The immune system should actually recognize and attack invading structures. The classic type 1 diabetes, on the other hand, is an autoimmune disorder, whereby the immune system selects and destroys the body’s own tissue.

What all autoimmune disorders have in common are detectable autoantibodies in the blood, which enables a clear diagnosis. Although the autoantibodies reflect the presence of an autoimmune disorder, they are not innate immunological messenger substances that attack bodily tissue.

Whoever is genetically prone to a specific autoimmune disorder is sure to have an increased risk of also acquiring other related autoimmune diseases. In the case of type 1 diabetes, a related disorder means: an autoimmune-mediated inflammatory alteration of the thyroid gland, coeliac disease and, very rarely, autoimmune polyendocrinopathy syndrome (APS).

Autoimmune thyroiditis
The thyroid gland looks like a butterfly, and is located in the throat in front of the windpipe (see illustration). It produces a hormone important for proper mental and physical development. An under-active thyroid gland in children can cause disorders such as stunted growth. For further symptoms, see table. If the thyroid gland succumbs to an autoimmune reaction, ie, if it is attacked by the body’s own immune system, it becomes inflamed and can no longer secrete sufficient hormone. In people with diabetes, Hashimoto’s thyroiditis, the most frequent type of thyroid disorder, occurs disturbingly frequently. Young girls after the onset of puberty are particularly prone, and also children, especially if another autoimmune disorder such as diabetes is present. 

Recognition of under activity …
Studies carried out in Germany have shown that around 10–15% of all children with type 1 diabetes have at least one characteristic antibody. The antibodies can appear both at onset of diabetes or much later.

An under-active thyroid usually takes years to develop. The organ usually becomes enlarged, because the body tries to compensate the under activity by building more thyroid cells. More rarely, a short over-activity takes place, and even more rarely, a ‘primary atrophic’ infection, whereby the thyroid gland shrinks.

Ultrasound pictures show a characteristic pattern typically seen in thyroid tissue alteration (salt and pepper chromatin), and blood tests show a characteristic autoantibody.

… and appropriate treatment
Not all cases of Hashimoto’s thyroiditis end up as manifest thyroid under-activity. It is not always appropriate to treat it with thyroid hormones. Hormone tablets should only be given if blood tests show a significant under-activity, or if the thyroid gland has enlarged as a compensatory measure. If, during the course of Hashimoto’s thyroiditis, under-activity does result, it subsides in 20% of the cases. Sometimes, after puberty, and if the acute infectious phase has subsided, it may be appropriate to try withholding treatment.

According to the Paediatric Diabetology Working Committee (Arbeitsgemeinschaft für pädiatrische Diabetologie), type 1 diabetic children and adolescents should be examined once a year for characteristic autoantibodies. If found, an ultrasound of the thyroid gland should be carried out, and metabolic parameters determined.

Diabetes and coeliac disease 
Coeliac disease, otherwise known as gluten-sensitive enteropathy, gluten-induced enteropathy, or coeliac sprue, is an autoimmunologically mediated intolerance in the intestine towards gluten—a gluey protein present in many grains such as rye, barley, oats and wheat. Children and adolescents with diabetes are 10 times more likely to succumb to coeliac disease than the rest of the population. Coeliac disease accounts for the most cases of disorders in otherwise well nourished children. Symptoms: severe diarrhea, chronic stomach ache, weight loss and growth cessation. In children and adolescents with diabetes, the classic symptoms do not appear but rather the appearance of more obscure factors such as lack of iron, delayed onset of puberty, and/or slowed growth. 

In coeliac disease, the intestinal membrane is inflamed, making it difficult for it to absorb nutrients. This inflammation represents yet another process in which the immune system plays a role. Everybody with type 1 diabetes should be screened for the development of coeliac disease, at diagnosis as well as yearly thereafter. The presence of transglutaminase antibodies and/or symptoms such as indigestion, diarrhea, flatulence and growth cessation indicates the presence of further antibodies that should be determined. For a truly accurate diagnosis, an intestinal biopsy should be performed.

Treating coeliac disease
Those suffering from coeliac disease should refrain from eating any foods containing gluten. This means the permanent avoidance of products containing wheat, barley, rye and oats. This diet should be held for life, even in the absence of symptoms, in order to avoid illness and, in diabetics, to keep blood sugar levels normal. If coeliac disease goes untreated, there is an increased risk of sudden hypoglycaemia.

Very rare: APS
In very rare cases, autoimmune polyendocrinopathy syndrome (APS) may appear. In this disease, not only is the thyroid gland, but also the adrenal glands are inflamed and attacked by the body’s own immune system. Signs and symptoms are calcium deficiency (shakiness, cramps, tingling of the mouth) or cortisol deficiency (extreme apathy, muscle weakness, extreme fatigue, increased hypoglycaemia). Because APS, in its many forms, is so rare, there is no recommendations regarding screening. If, however, any of the mentioned symptoms do appear, a diabetologist should be consulted.

Summary
Those who are genetically prone to type 1 diabetes also have a higher chance of acquiring other autoimmune disorders. Hashimoto’s autothyroiditis (inflammation of the thyroid gland) appears relatively frequently, as well as coeliac disease (inflammation of the intestinal mucuous membrane with gluten intolerance). Albeit very rarely, autoimmune polyendocrinopathy syndrome (APS: inflammation of the adrenal glands) may also appear.

The thyroid glands should be examined in children and adolescents with type 1 diabetes once a year, as well as a test for coeliac disease. APS should only be suspected if symptoms of calcium or cortisol defiencies appear.

Contact
Claudia Nestoris MD
Kinderkrankenhaus auf der Bult
Hannover
E-Mail: nestoris@hka.de