Endocrine Abstracts

Introduction: Thyrotoxicosis resistant to the usual treatment is rare, but potentially fatal. In such situations, the optimal next treatment is unclear. Iopanoic acid (IA) was historically used as an oral contrast agent; it’s capacity to treat thyrotoxicosis has been limited in recent years due to its restricted availability.Methods: Retrospective case note review of patients treated with IA for resistant thyrotoxicosis at our institution over the p...

Case history: A clinically euthyroid 7-year-old boy was noted to have a persistently elevated TSH 7.35–14 mU/l (NR 0.27–4.2) and normal FT4 15.0 pmol/l (NR 10-24) with negative anti-thyroid peroxidase antibodies. Thyroid ultrasonography revealed a eutopically-located thyroid gland of normal size. Following commencement of levothyroxine, he developed insomnia, irritability and headaches, resulting in cessation of treatment. Growth and development proceeded ...

Introduction: Familial dysalbuminemic hyperthyroxinemia (FDH) is characterized by artefactual hyperthyroxinemia caused by enhanced binding affinity of thyroxine to the mutant albumin. However little is known about how FDH affects the measurement of thyroid hormones, especially FT3, across many assay platforms.Methods: Forty-eight genetically confirmed FDH patients (R218H mutation) had FT4 and FT3 measured with 1-step (ADVIA CENTAUR®, Siem...

Background: 21-Hydroxylase deficiency due to mutations in CYP21A2 represents the commonest form of congenital adrenal hyperplasia (CAH). Dyshormonogenetic congenital hypothyroidism (CH) may be due to TPO, TG, DUOX2, DUOXA2, IYD, SLC5A5 and SLC26A4 mutations.Case report: Two of six children born to unrelated parents presented in the neonatal period with salt-losing CAH due to compound heterozygosity in CYP21A2 (maternal...

Corepressors and coactivators of thyroid hormone receptor-mediated function facilitate repression and transactivation of positively-regulated target genes respectively, but their role in negative regulation is not understood. A 13 yr old boy, born at 31 weeks gestation, was jittery at birth, with neonatal respiratory distress. Childhood features included poor weight gain, heat intolerance, tachycardia and hyperactivity. Ongoing problems are low frequency hearing loss, poor sig...

Metyrapone (MT) is used in the medical management of Cushing’s syndrome as it decreases serum cortisol (CT) levels by inhibiting adrenal β-hydroxylation of 11-deoxycortisol, the final step in CT synthesis. CT precursors, in particular 11-deoxycortisol (DOC), increase following MT therapy. Monitoring glucocorticoid replacement in patients taking MT could therefore be confounded as DOC cross-reacts in commonly used immunoassays (IA) for serum CT. Serum CT results from ...

We report five cases of hyperthyroidism with complex management issues, which were successfully treated with iopanoic acid prior to thyroidectomy.Three patients (cases 1–3) had Graves’ disease; two developed agranulocytosis on carbimazole and one had uncontrolled severe thyrotoxicosis and poor compliance with treatment. Radioiodine was either declined or contraindicated due to radio-protection issues. All patients were rendered euthyroid with i...

The differential diagnosis of raised circulating thyroid hormones with normal TSH includes familial dysalbuminaemic hyperthyroxinaemia (FDH), a benign, inherited disorder caused by a variant albumin with increased affinity for thyroxine (T4) or triiodothyronine (T3). Three different albumin gene mutations, generating mutant proteins with increased affinity for either T4 (R218H,R218P) or T3 (L66P) have been commonly described. Typically, serum total T4 is raised and free T4 mea...

Resistance to thyroid hormone (RTH) is a rare, autosomal dominant disorder characterised by a reduced sensitivity of peripheral tissues to thyroid hormone. Thyroid function testing shows elevation of free T4 and T3 with non suppressed TSH levels.Vascular function in these patients has not been fully evaluated. We have studied central arterial stiffness in a cohort of RTH patients, comparing them with age and sex matched controls.Me...

Background: Thyrotropin secreting adenomas (TSHoma) are considered to be rare pituitary tumours. However, improvements in imaging techniques and greater use of more sensitive thyrotropin (TSH) assays has led to a recent increase in the detection rate of TSHomas and, specifically, the identification of more microadenomas. Surgery is considered the mainstay of treatment, however, primary medical therapy with somatostatin analogues is an emerging alternative therapeutic option.</...