Subklinische Hypothyreose

Was ist neu?

Definition und Epidemiologie Die subklinische Hypothyreose ist in der Regel eine Labordiagnose ohne signifikante Symptomatik und definiert durch ein erhöhtes TSH bei normalen Werten für freies T3 und freies T4. Bei Laborkontrollen nach 2–3 Monaten findet sich in 50 % der Fälle eine spontane Normalisierung.

Klinische Bedeutung der subklinischen Hypothyreose Bei persistierend erhöhten TSH-Werten ist die subklinische Hypothyreose mit dem Nachweis von schilddrüsenspezifischen Antikörpern im Sinne einer Autoimmunthyreoiditis assoziiert. Im Alter finden sich physiologisch höhere TSH-Spiegel. Es ist deshalb davon auszugehen, dass die Diagnose einer subklinischen Hypothyreose bei älteren Menschen über 70 Jahre zu häufig gestellt und therapiert wird.

Therapie der subklinischen Hypothyreose Studien konnten bisher keinen positiven Effekt einer Substitutionstherapie der subklinischen Hypothyreose zeigen, insbesondere nicht bei älteren Patienten. Andererseits besteht das nicht unerhebliche Risiko einer Übertherapie mit der Entwicklung einer subklinischen Hyperthyreose. Deren negative Folgen in Form von Vorhofflimmern und Osteoporose beeinträchtigen die Lebensqualität und -dauer. Bei der Indikationsstellung zur Substitutionstherapie einer subklinischen Hypothyreose sollte deshalb zurückhaltend vorgegangen werden.

Subklinische Hypothyreose in der Schwangerschaft Eine Gruppe, bei der Diagnostik und Therapie besondere Sensibilität erfordern, sind schwangere Frauen. Hier müssen mit Mutter und Kind 2 Individuen behandelt werden. Dabei sind veränderliche Zielwerte und Dosierungen bezogen auf das Schwangerschaftsalter zu berücksichtigen.

Abstract

Subclinical hypothyroidism is usually a laboratory diagnosis without significant symptoms and is defined by an elevated thyroid-stimulating hormone (thyrotropin, TSH) with normal thyroid hormone levels. On laboratory checks after two to three months, spontaneous normalization is found in 50 % of all cases in the sense of a transient elevation.

With persistently elevated TSH levels, subclinical hypothyroidism is associated with evidence of thyroid-specific antibodies in the sense of autoimmune thyroiditis. Physiologically higher TSH levels are found in old age. It can therefore be assumed that the diagnosis of subclinical hypothyroidism is made and treated too frequently in older people over 70 years of age.

Studies have so far failed to show a positive effect of substitution therapy of subclinical hypothyroidism, especially in elderly patients. On the other hand, there is a not inconsiderable risk of overtreatment with the development of subclinical hyperthyroidism. Its negative consequences in the form of atrial fibrillation and osteoporosis impair the quality and duration of life. Therefore, the indication for substitution therapy of subclinical hypothyroidism should be made with caution.

One group in which diagnosis and therapy require special sensitivity is pregnant women. Here, two individuals, mother and child, must be treated. Varying target values and dosages in relation to the gestational age must be taken into account.

Schlüsselwörter

Hypothyreose - Hormonersatztherapie - Altersfaktoren - Thyroxin/therapeutische Verwendung

Key words

hypothyroidism - hormone replacement therapy - age factors - thyroxine/therapeutic use

Publication History

Article published online:
15 March 2022

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