The Study
Familial inappropriate TSH secretion: evidence suggesting a dissociated pituitary resistance to T3 and T4
This study is like noticing that one person’s car won’t start when they use one kind of gas but works fine with another. It’s interesting, but it doesn’t prove that gas type always causes cars to break down — maybe this car is just weird.
Analysis score
Maximum 30 for a case report.
Where the score came from
A woman had high thyroid hormones in her blood but felt fine and didn't need treatment—yet her brain kept telling her thyroid to make more hormone, like a broken thermostat.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 520 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—this means doctors can't rely only on TSH to judge thyroid health; sometimes the brain is blind to T4 but still hears T3, so treatment must be tailored.
- 2Her TSH was 8.2–29 (normal: 0.4–4.0), T4 was 13.4 μg/dL (normal: 5–12), T3 was 255 ng/dL (normal: 80–200).
- 3Giving her T3 lowered TSH; giving her T4 did not.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Endocrinological Investigation
Year
1981
Authors
J. Vandalem, G. Pirens, G. Hennen
Related Content
Claims (6)
When thyroid hormone levels rise in the blood, the pituitary gland reduces its production of thyroid-stimulating hormone (TSH).
A 40-year-old woman with normal thyroid function had high thyroid-stimulating hormone (TSH) levels despite high levels of both thyroxine (T4) and triiodothyronine (T3). When T3 was given, TSH dropped, but T4 did not suppress TSH, showing that the pituitary gland responds to T3 but not to T4.
In people with normal thyroid function but high TSH levels, giving T3 hormone reduces TSH levels, but giving T4 hormone does not reduce TSH levels, showing that the pituitary gland responds differently to these two thyroid hormones.
In people with normal thyroid function but high TSH and normal to high T4 and T3 levels, measuring TSH by itself does not accurately reflect thyroid hormone activity because the pituitary gland does not respond normally to T4.
In one individual, thyroid-stimulating hormone levels remained high despite high levels of thyroxine, but responded normally to triiodothyronine, and this pattern was observed in other family members, indicating a unique inherited form of thyroid hormone resistance.
A specific pattern of thyroid hormone levels—high TSH with normal to high T4 and T3, along with selective suppression by T3—represents a unique medical condition different from known forms of thyroid hormone resistance.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.