Diagnosis | Hypothyroidism

Diagnosis

In order to be able to make a diagnosis of hypothyroidism, your attending physician will first have a detailed conversation about your current symptoms and the family history of your condition. The doctor will also be interested in the question of your eating habits, in order to uncover any iodine deficiency due to insufficient iodine intake through food. The so-called anamnesis interview is followed by a physical examination.The examiner positions himself behind the patient and palpates the neck region with both hands.

The palpation findings can, for example, provide indications of an enlargement of the thyroid gland. If hypothyroidism is suspected, an ultrasound scan is performed on the patient lying down. The ultrasound provides information on the size, condition, location and structure of the thyroid gland.

An additional examination as part of the diagnostic clarification of hypothyroidism can be carried out using the so-called scintigraphy. Here, a radioactively marked substance is introduced into the body’s circulation via a vein. Normally, this substance accumulates in the thyroid tissue and can be visualized.

If the thyroid gland is hypothyroid, the thyroid gland absorbs the substance at a reduced rate. This examination method is not routine in the diagnosis of hypothyroidism, but is used for certain problems. If hypothyroidism is suspected, a blood test is performed to determine the thyroid gland values.

The so-called TSH value, T3 and T4 are determined. The TSH value, short for thyroid-stimulating hormone, is produced in the central nervous system in the pituitary gland and stimulates the thyroid to produce hormones via the bloodstream. In primary hypothyroidism, the TSH level is elevated because the negative feedback mechanism to the brain is absent due to the deficient production of T3 and T4, thus massively stimulating the production of TSH.

In secondary hypothyroidism, the problem lies in the brain, the place where TSH is produced, which is why the level is lowered. A normal TSH value largely rules out hypothyroidism. The thyroid hormones T3 and T4 can still be in the normal range (latent hypothyroidism), in the lower normal range or reduced.

In the latter case, this is referred to as manifest hypothyroidism. If acquired Hashimoto’s thyroiditis is suspected, the thyroglobulin and thyroperoxidase antibodies in the blood are also determined. In newborns the obligatory screening is carried out by examination of heel blood with subsequent determination of the laboratory values already mentioned.

At the legally required hypothyroidism screening as part of the newborn screening on the 2nd – 3rd day of the child’s life, an underactive thyroid can be detected: The concentration of TSH is determined. This hormone causes the release of the thyroid hormones T3 and T4. A few drops of blood are taken from the heel of the newborn between the 36th and 72nd hour of life and dripped onto a special filter paper.

In congenital hypothyroidism, the concentrations of T3 and T4 are lowered because the thyroid does not produce them or does not produce them sufficiently. Due to this under- or underproduction of hormones, the TSH value is increased. The control cycle then increases the TRH and TSH levels with the aim of increasing thyroid hormone production. Since the thyroid gland cannot react to this stimulus, the hormone deficiency situation remains with an increased TSH value.