Related Experiment Videos
[Inadequate TSH secretion. Clinical features, diagnostic criteria, and therapeutic possibilities]
A Caixàs1, F Infiesta, M Balsells
1Servicio de Endocrinología, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona.
Medicina Clinica
|May 28, 1994
Summary
Inadequate secretion of TSH (Thyroid-Stimulating Hormone) is increasingly diagnosed. Differentiating neoplastic from non-neoplastic causes requires careful evaluation of TSH levels and rhythms.
Area of Science:
- Endocrinology
- Molecular Biology
- Clinical Medicine
Background:
- Inadequate secretion of TSH (IST) is a disorder diagnosed more frequently with advanced immunoassay techniques.
- Diagnosis requires high or unsuppressed TSH levels alongside elevated thyroid hormones.
- Etiologies include TSH-secreting pituitary adenomas or resistance to thyroid hormones.
Observation:
- Five IST cases were analyzed for diagnostic, clinical, and therapeutic criteria.
- Neoplastic IST cases (3) showed loss of TSH circadian rhythm and no suppression with T3, TRIAC, or bromocriptine.
- Non-neoplastic IST cases (2) maintained TSH circadian rhythm and suppressed with T3, TRIAC, and bromocriptine.
Findings:
- TSH circadian rhythm and suppression response to T3, TRIAC, and bromocriptine differentiate neoplastic from non-neoplastic IST.
- Subunit-alpha/TSH quotient and TSH response to TRH were variable.
- Metoclopramide showed no stimulation in any case.
Implications:
- Suspect IST in biochemical hyperthyroidism with unsuppressed TSH to prevent misdiagnosis and erroneous treatment.
- Distinguishing neoplastic from non-neoplastic IST can be challenging due to non-discriminatory biochemical and neuropharmacologic parameters.
- Further research into discriminatory diagnostic markers for IST is warranted.