Background and aims: Retrospective, observational study to compare clinical symptoms and TSH-receptor antibodies (TRAb) in Graves' ophthalmopathy (GO) in euthyroid and primarily hypothyroid patients to those in hyperthyroid patients.
Methods: Clinical symptoms (NOSPECS [severity] and CAS [activity] score), prevalence and levels of thyroid specific antibodies and the course of the disease were evaluated in 143 primarily hyperthyroid, 28 primarily euthyroid and 11 primarily hypothyroid patients with GO.
Results: Patients with euthyroid/hypothyroid GO developed significantly less severe GO symptoms (NOSPECS score 4.4 versus 5.7; p=0.03), less active GO (CAS score 3.9 versus 5.2; p=0.002) and more asymmetric disease (proptosis side difference: 1.9mm versus 1.0mm [p=0.01]; side difference of ≥ 3mm: 23% versus 4.8%) than hyperthyroid patients. TRAb levels 6 months after GO onset were significantly lower (2.2 IU/l, p=0.02) in euthyroid/hypothyroid than in hyperthyroid patients (8.6 IU/l) as were prevalence of both TRAb and TPO antibodies (75% versus 94.6%, p=0.0008).
Conclusions: The knowledge about the phenotype of GO in primarily euthyroid and hypothyroid patients is helpful for differential diagnosis and patient consultation. TRAb titres are very low in these patients, and the availability of a sensitive assay technique is therefore an important diagnostic tool in euthyroid and hypothyroid patients.