Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2014) 34 P423 | DOI: 10.1530/endoabs.34.P423

SFEBES2014 Poster Presentations Thyroid (51 abstracts)

Autoimmune thyroid disease in the presence of resistance to thyroid hormone or TSH-secreting pituitary tumour: a diagnostic challenge

Carla Moran , Olympia Koulouri , Fleur Talbot , Catherine Mitchell , Nadia Schoenmakers , Greta Lyons , Mark Gurnell & V K K Chatterjee


Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.


Background: Hyperthyroxinaemia with non-suppressed TSH, due to resistance to thyroid hormone (RTH) or TSH-secreting pituitary tumour (TSHoma), can be difficult to diagnose, particularly with coincident autoimmune thyroid disease (AITD).

Methods: To determine presentation patterns of AITD coincident with RTH or TSHoma, we analysed our cohort of cases with dual diagnoses.

Results: Nine patients with RTH had AITD. Six had Graves’ disease (GD); RTH was suspected when anti-thyroid drug treatment led to unexpected TSH increase despite hyperthyroxinaemia (e.g. initial TSH <0.03 mU/l, TT4 300 nmol/l; post carbimazole TSH 6 mU/l, TT4 150 nmol/l (NR 50–150)) or when hyperthyroxinaemia was associated with incompletely suppressed TSH (e.g. FT4 89.6 pmol/l, FT3 26.7 pmol/l, TSH 0.04 mU/l during GD flare-up, with baseline TSH 1.7 mU/l, FT4 27.9 pmol/l, FT3 16.7 pmol/l). Three had autoimmune hypothyroidism with elevated TSH levels but high-normal TH (e.g. TSH 29.8 mU/l, FT4 20.8 pmol/l, FT3 7.2 pmol/l) and positive anti-TPO antibody titres.

Two patients with TSHoma had coincident AITD; the first presented with an elevated TSH and concomitant mild hyperthyroxinaemia (TSH 35.2 mU/l, FT4 22.2 pmol/l), the second presented with failure to suppress TSH after levothyroxine for presumed primary hypothyroidism (TSH 5.9 mU/l, FT4 25 pmol/l, on 50 μg of levothyroxine). Both had raised TPO antibody titres.

20% of our genetically heterogeneous RTH cohort (n=160) without known AITD, are anti-TPO antibody positive, but all are anti-TSHR antibody negative.

Conclusion: Resistance within the HPT axis (RTH) or inappropriate TSH secretion (TSHoma) should be suspected in i) autoimmune hypothyroidism where physiological dose thyroxine replacement fails to correct elevated TSH, ii) thyrotoxic patients with incompletely suppressed TSH especially when normalisation of TH levels in response to anti-thyroid drug treatment results in exaggerated TSH rise and iii) patients with elevated TSH but high-normal TH concentrations. Lastly, the increased prevalence of positive thyroid autoantibodies in RTH suggests these patients may be at greater risk of developing AITD.

Article tools

My recent searches

No recent searches.