Latente Hypothyreose – Laborkonstellation oder Krankheit?

Zusammenfassung

Die Konstellation einer latenten Hypothyreose (erhöhtes TSH und normwertiges Thyroxin) sollte kontrolliert und deren Ursache abgeklärt werden. Aktuelle Studienergebnisse sind hinsichtlich der klinischen Relevanz einer latenten Hypothyreose beruhigend und sprechen dafür, dass die Diskussionen um den oberen TSH-Referenzbereich und viele sich daraus ergebenden Behandlungsforderungen unnötig sind. Die Mehrzahl der Studien und Metaanalysen zeigt bei TSH-Werten zwischen 5–10 mIU / l keine Assoziation mit Mortalität, kardiovaskulären Ereignissen, Frakturrate und kognitiven Einschränkungen. Altersbezogen gibt es sogar Hinweise, dass TSH-Werte von 5–10 mIU / l bei alten Menschen mit einer geringeren Mortalität einhergehen, also protektiv sind. Dies sind Argumente, mit der Diagnose einer Schilddrüsenfehlfunktion zurückhaltender zu sein. Die Indikation zur Levothyroxinsubstitution ist bei nur gering erhöhten TSH-Werten < 8–10 mIU / l individuell zu stellen. Bei Autoimmunthyreoiditis oder vorausgegangener Schilddrüsentherapie (OP, Radiojodtherapie) ist insbesondere das Risiko der Entwicklung einer manifesten Hypothyreose zu bedenken und diese sollte selbstverständlich vermieden werden.

Abstract

Subclinical hypothyroidism first of all is a laboratory finding, defined by elevated TSH and normal peripheral thyroxine concentrations. The first steps are to verify the condition and to clarify whether the patient has underlying thyroid disease or other comorbidities. Results of recent studies on subclinical hypothyroidism are reassuring. No consistent association has been demonstrated between mildly elevated TSH levels (5–10 mIU / l) and cardiovascular events, mortality, fracture risk or cognitive impairment. In contrast TSH levels between 5–10 mIU / l may even confer lower mortality in the elderly and may hence be protective. These data strongly suggest that the long-time controversy on definition of normal upper TSH levels should take a more conservative turn. Thus, diagnosis of subclinical hypothyroidism should be handled cautiously. Individualized treatment decision is recommended if TSH levels are only mildly elevated and less than 8–10 mIU / l. In case of autoimmune thyroiditis or previous thyroid therapy (surgery, radioiodine treatment) the risk of progression to overt hypothyroidism has to be considered and there is no doubt that the latter should be avoided.

Schlüsselwörter

latente Hypothyreose - subklinische Hypothyreose - Diagnose - Therapie

Keywords

subclinical hypothyroidism - diagnosis - treatment - therapy

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