23 research outputs found
A somatic mutation in the thyrotropin receptor gene in a patient with an autonomous nodule within a multinodular goiter
ABSTRACT Thyrotropin (TSH) is the prime regulator of thyroid cell growth and function and acts through the thyrotropin receptor (TSHR) located on the surface membrane of thyrocytes. Somatic heterozygous mutations that cause TSHR activation in the absence of TSH have been found in toxic adenomas and in hot nodules of multinodular goiters. Clinically and histologically heterogeneous nodules can share common gain-of-function mutations. Mutation prevalence varies greatly and is inversely related to iodine intake of the population. We report a Greek patient presenting with subclinical hyperthyroidism due to a fast-growing autonomous hyperplastic nodule in a long-standing multinodular goiter. Direct DNA sequencing showed that the hot nodule harbored a somatic heterozygous activating TSHR mutation: substitution of glutamine for leucine in the third transmembrane helix. This mutation (L512Q) was recently described in two solitary toxic adenomas. This report expands the spectrum of mutations shared by dissimilar hot nodules, supporting a common mechanism for nonautoimmune thyroid autonomy. The identification of the L512Q substitution demonstrates that gainof-function TSHR mutations are encountered in Greece, although iodine deficiency has been significantly corrected over the last three decades
The nonthyroidal illness syndrome in the non-critically ill patient
P>Background
The nonthyroidal illness syndrome (NTIS) is a very common clinical
entity among hospitalized patients and has been reported in practically
every severe illness and acute or chronic stressful event. There is a
large body of data associating the presence of NTIS with the severity of
the underlying disease. Most of these studies concern intensive care
unit (ICU) patients, whereas the non-critically ill patients outside the
ICU setting are less well studied.
Design
We provide a review of the existing literature focusing on studies
examining NTIS in non-critically ill patients and attempt to summarize
the pathophysiological pathways underlying the syndrome, its prognostic
role, as well as the current intervention studies mainly from a clinical
standpoint.
Results
The aetiology of the NTIS is multifactorial and varies among different
groups of patients. Experimental and clinical findings suggest that
inflammatory cytokines are implicated in the pathogenesis of the
syndrome, whereas recent evidence re-evaluate the role of deiodinases in
thyroid hormone metabolism not only in the periphery but also in the
hypothalamus and the pituitary and thus in the alterations accompanying
NTIS. Clinical data examining the effectiveness of thyroid hormone
supplementation in NTIS remain controversial.
Conclusions
As long as there is no clear evidence of benefit from thyroid hormone
replacement and until well-designed studies confirm its efficacy,
thyroxine supplementation should not be recommended for the treatment of
NTIS