Autoimmune Addison's disease
ABSTRACT Addison's disease is a rare autoimmune disorder. In the developed world, autoimmune adrenalitis is the commonest cause of primary adrenal insufficiency, where the majority of patients have circulating antibodies against the key steroidogenic enzyme 21-hydroxylase. A complex interplay of genetic, immunological and environmental factors culminates in symptomatic adrenocortical insufficiency, with symptoms typically developing over months to years. Biochemical evaluation and further targeted investigations must confirm primary adrenal failure and establish the underlying aetiology. The diagnosis of adrenocortical insufficiency will necessitate lifelong glucocorticoid and mineralocorticoid replacement therapy, aiming to emulate physiological patterns of hormone secretion to achieve well-being and good quality of life. Education of patients and healthcare professionals is essential to minimise the risk of a life-threatening adrenal crisis, which must be promptly recognised and aggressively managed when it does occur. This article provides an overview of our current understanding of the natural history and underlying genetic and immunological basis of this condition. Future research may reveal novel therapeutic strategies for patient management. Until then, optimisation of pharmacological intervention and continued emphasis on education and empowerment of patients should underpin the management of individuals with autoimmune Addison's disease.
- La Presse Médicale 11/2012; 41(12). DOI:10.1016/j.lpm.2012.10.004
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ABSTRACT: Estrogen-related receptors (ERRs) are orphan nuclear hormone receptors expressed in metabolically active tissues and modulate numerous homeostatic processes. ERRs do not bind the ligand estrogen, but they are able to bind the estrogen response element (ERE) embedded within the ERR response elements (ERREs) to regulate transcription of genes. Previous work has demonstrated that adult mice lacking Errbeta have altered metabolism and meal patterns. To further understand the biological role of Errbeta, we characterized the stress response of mice deficient for one or both alleles of Errbeta. Sox2-Cre:Errbeta mice lack Errbeta expression in all tissues of the developing embryo. Sox2-Cre:Errbeta+/lox heterozygotes were obese, had increased Npy and Agrp gene expression in the arcuate nucleus of the hypothalamus, and secreted more corticosterone in response to stress. In contrast, Sox2-Cre:Errbetalox/lox homozygotes were lean and, despite increased Npy and Agrp gene expression, did not secrete more corticosterone in response to stress. Sox2-Cre:Errbeta+/lox and Sox2-Cre:Errbetalox/lox mice treated with the Errbeta and Errgamma agonist DY131 demonstrated increased corticotropin-releasing hormone (Crh) expression in the paraventricular nucleus of the hypothalamus, although corticosterone levels were not affected. Nes-Cre:Errbetalox/lox mice, which selectively lack Errbeta expression in the nervous system, also demonstrated elevated stress response during an acoustic startle response test and decreased expression of both Crh and corticotropin-releasing hormone receptor 2 (Crhr2). Loss of Errbeta affects body composition, neuropeptide levels, stress hormones, and centrally-modulated startle responses of mice. These results indicate that Errbeta alters the function of the hypothalamic-pituitary-adrenocortical axis and indicates a role for Errbeta in regulating stress response.BMC Physiology 09/2013; 13(1):10. DOI:10.1186/1472-6793-13-10
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ABSTRACT: Subclinical hypothyroidism (SCH) should be considered in two categories according to the elevation in serum thyroid-stimulating hormone (TSH) level: mildly increased TSH levels (4.0-10.0 mU/l) and more severely increased TSH value (>10 mU/l). An initially raised serum TSH, with FT4 within reference range, should be investigated with a repeat measurement of both serum TSH and FT4, along with thyroid peroxidase antibodies, preferably after a 2- to 3-month interval. Even in the absence of symptoms, replacement therapy with L-thyroxine is recommended for younger patients (<65-70 years) with serum TSH >10 mU/l. In younger SCH patients (serum TSH <10 mU/l) with symptoms suggestive of hypothyroidism, a trial of L-thyroxine replacement therapy should be considered. For such patients who have been started on L-thyroxine for symptoms attributed to SCH, response to treatment should be reviewed 3 or 4 months after a serum TSH within reference range is reached. If there is no improvement in symptoms, L-thyroxine therapy should generally be stopped. Age-specific local reference ranges for serum TSH should be considered in order to establish a diagnosis of SCH in older people. The oldest old subjects (>80-85 years) with elevated serum TSH ≤10 mU/l should be carefully followed with a wait-and-see strategy, generally avoiding hormonal treatment. If the decision is to treat SCH, then oral L-thyroxine, administered daily, is the treatment of choice. The serum TSH should be re-checked 2 months after starting L-thyroxine therapy, and dosage adjustments made accordingly. The aim for most adults should be to reach a stable serum TSH in the lower half of the reference range (0.4-2.5 mU/l). Once patients with SCH are commenced on L-thyroxine treatment, then serum TSH should be monitored at least annually thereafter.12/2013; 2(4):215-228. DOI:10.1159/000356507