Thyroid function and morphology after a successful kidney transplantation

Abstract

Although thyroid disorders related to the end-stage renal disease (ESRD) are well known, there are discordant data on the function and morphology of the thyroid gland after renal transplantation (RT). The objective of this cross-sectional, case-control study was to investigate the prevalence and risk factors for disorders in the thyroid function and morphology after a successful RT. Fifty consecutive patients (25 females, 25 males) with fully functioning allograft were enrolled. Their age at transplant ranged from 23 to 44 yr (median, 38) and their post-RT follow-up lasted 15-86 months (median, 23). One hundred healthy subjects matched for sex, age and body mass index (BMI) were included as controls. Serum free thyroid hormones, TSH, thyroglobulin, thyroid hormone-binding globulin (TBG) and iodine urinary excretion were determined; ultrasonographic exam of the thyroid gland was performed in all subjects. Age, gender, time elapsed from RT, dialysis duration, kidney function, type of immunosuppression and corticosteroid dose were considered as possible influencing factors for the thyroid function. Hypothyroidism was found in 6% of patients, "low T3 syndrome" in 52%, while another 26% had free T3 (FT3), free T4 (FT4) and TSH in the lowest third of the normal range, suggesting inhibition of the whole hypothalamic-pituitary-thyroid (HPT) axis. Iodine excretion and prevalence of anti-thyroid antibodies were similar in both patients and controls. There was no significant difference in the thyroid function according to different immunosuppressive regimens. In patients, an ultrasonographic exam revealed a very variable thyroid volume ranging from 7.2 to 24.8 ml. Solid nodules were detected in 12 (24%) cases and cystic lesions in another four (8%); they were proven negative at cytological examination. Dialysis duration was longer in patients with thyroid nodules than in those without (p<0.05). Inhomogeneous hypoechoic pattern typical for chronic thyroiditis was more frequent than its biochemical expression. In conclusion, a high prevalence of abnormal thyroid morphology was found in patients after a successful RT, being partly related to a previous uremia. Abnormalities in the thyroid function are likely an expression of the post-transplant general and immunological conditions. Endocrinological follow-up is advisable in patients after RT, in order to discriminate thyroid dysfunctions which need specific treatments from those that can only be followed-up, avoiding inappropriate treatments of biochemical abnormalities.

Incidence of Thyroid Dysfunction and Thyroid Cancer in Renal Transplant Recipients: A Single Center Experience

“…[9] Our results support the previous reports that show that the presence of thyroid nodules is not related to age, duration of dialysis, or TSH. [1] Contrary to these results, Tauchmanova et al [3] described that duration of dialysis increased the occurrence of thyroid nodules. We did not demonstrate any effect of duration of dialysis on the development of thyroid nodules.…”

“…The prevalence of thyroid cancers has been reported to be between 0 and 11.4% in these studies. [1][2][3][4][5] We found no reported thyroid cancer in Turkish transplant patients in Pubmed database. However, in a study of 2817 chronic renal failure patients from Turkey, which is considered an iodine-deficient country, only 10 papillary thyroid cancer and 3 unspecified thyroid cancers have been reported.…”

“…There is conflicting data in the literature regarding thyroid cancer in the renal transplant population. [1][2][3][4][5] The fact that the majority of studies are retrospective investigations of transplant patients who were surgically treated is also another disadvantage when evaluating these studies. The prevalence of thyroid cancers has been reported to be between 0 and 11.4% in these studies.…”

“…[2] Also, Tauchmanova et al found no patients with thyroid cancer in a prospective follow-up of 50 RT recipients during an average follow-up period of 23 months. [3] Thus, data are minimal and conflicting regarding thyroid cancer risk after renal transplantation.…”

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“…3 Thyroid disorders have been frequently reported in ESRD patients, although poorly investigated in kidney transplant recipients, and the data are conflicting. [4][5][6] In this study, we analyzed thyroid disorders via fine-needle aspiration (FNA) biopsy results and incidence of thyroid cancer in patients with ESRD.…”