TSH ratio as a novel diagnostic method for Cushing's syndrome

The application value of CDFI and SMI combined with serological markers in distinguishing benign and malignant thyroid nodules

PURPOSE

The purpose of this study is to explore the application value of CDFI and SMI combined with serological markers in distinguishing benign and malignant thyroid nodules.

METHOD

A total of 192 patients with thyroid nodules admitted to our hospital from July 2019 to December 2020 were selected as subjects. Color Doppler blood flow imaging (CDFI) and supermicro blood flow imaging (SMI) methods are used to detect the blood flow of patients and the levels of serum thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), and thyroid stimulating hormone (TSH). The receiver operating characteristic curve (ROC curve) was used to observe the sensitivity and specificity of serological markers for distinguishing benign and malignant thyroid nodules, and combined with CDFI and SMI to observe the sensitivity and specificity for distinguishing benign and malignant thyroid nodules.

RESULTS

The levels of TgAb, TPOAb and TSH in benign thyroid nodules were lower than those of the malignant group, and the difference was statistically significant (P < 0.01). There was no statistically significant difference between benign and malignant thyroid nodules in the presence or absence of the capsule and the presence or absence of vocal halo (P > 0.05), while the differences in the nodule morphology, boundary, internal echo and internal calcification were statistically significant (P < 0.01).

CONCLUSION

CDFI and SMI combined with serological index detection have higher value in the differential diagnosis of thyroid cancer, which can significantly improve the sensitivity and specificity of differential diagnosis.

Cushing's Syndrome Effects on the Thyroid

The most known effects of endogenous Cushing’s syndrome are the phenotypic changes and metabolic consequences. However, hypercortisolism can exert important effects on other endocrine axes. The hypothalamus–pituitary–thyroid axis activity can be impaired by the inappropriate cortisol secretion, which determinates the clinical and biochemical features of the “central hypothyroidism”. These findings have been confirmed by several clinical studies, which also showed that the cure of hypercortisolism can determine the recovery of normal hypothalamus–pituitary–thyroid axis activity. During active Cushing’s syndrome, the “immunological tolerance” guaranteed by the hypercortisolism can mask, in predisposed patients, the development of autoimmune thyroid diseases, which increases in prevalence after the resolution of hypercortisolism. However, the immunological mechanism is not the only factor that contributes to this phenomenon, which probably includes also deiodinase-impaired activity. Cushing’s syndrome can also have an indirect impact on thyroid function, considering that some drugs used for the medical control of hypercortisolism are associated with alterations in the thyroid function test. These considerations suggest the utility to check the thyroid function in Cushing’s syndrome patients, both during the active disease and after its remission.

The Hypothalamic-Pituitary-Thyroid Axis in Cushing Syndrome Before and After Curative Surgery

BACKGROUND

We do not fully understand how hypercortisolism causes central hypothyroidism or what factors influence recovery of the hypothalamic-pituitary-thyroid axis. We evaluated thyroid function during and after cure of Cushing syndrome (CS).

METHODS

We performed a retrospective cohort study of adult patients with CS seen from 2005 to 2018 (cohort 1, c1, n = 68) or 1985 to 1994 (cohort 2, c2, n = 55) at a clinical research center. Urine (UFC) and diurnal serum cortisol (F: ~8 am and ~midnight [pm]), morning 3,5,3'-triiodothyronine (T3), free thyroxine (FT4), and thyrotropin (TSH) (c1) or hourly TSH from 1500 to 1900 h (day) and 2400 to 04000 h (night) (c2), were measured before and after curative surgery.

RESULTS

While hypercortisolemic, 53% of c1 had central hypothyroidism (low/low normal FT4 + unelevated TSH). Of those followed long term, 31% and 44% had initially subnormal FT4 and T3, respectively, which normalized 6 to 12 months after cure. Hypogonadism was more frequent in hypothyroid (69%) compared to euthyroid (13%) patients. Duration of symptoms, morning and midnight F, adrenocorticotropin, and UFC were inversely related to TSH, FT4, and/or T3 levels (r = -0.24 to -0.52, P < .001 to 0.02). In c2, the nocturnal surge of TSH (mIU/L) was subnormal before (day 1.00 ± 0.04 vs night 1.08 ± 0.05, P = .3) and normal at a mean of 8 months after cure (day 1.30 ± 0.14 vs night 2.17 ± 0.27, P = .01). UFC greater than or equal to 1000 μg/day was an independent adverse prognostic marker of time to thyroid hormone recovery.

CONCLUSIONS

Abnormal thyroid function, likely mediated by subnormal nocturnal TSH, is prevalent in Cushing syndrome and is reversible after cure.

Biochemical diagnosis of Cushing's disease: Screening and confirmatory testing

Due to the variable clinical features and its rarity diagnosis of Cushing's disease (CD) is often delayed. Clearly, awareness for CD needs to be raised, accompanied by the availability of simple and accurate screening tests. Late-night salivary cortisol (LNSC), 1 mg dexamethasone suppression test (DST), and urinary free cortisol (UFC) have all been extensively studied, demonstrating high sensitivity and specificity for the diagnosis of Cushing's syndrome. However, each of those well-established tests has its own distinctive features, making it preferable in specific clinical conditions and patient groups. To choose the most appropriate test in individual patients, an expert endocrinologist should be consulted. This review will discuss the pitfalls for each of those tests.

Accuracy of Laboratory Tests for the Diagnosis of Cushing Syndrome

CONTEXT

The diagnosis of Cushing syndrome (CS) can be challenging. It remains to be determined which diagnostic tests are the most accurate.

OBJECTIVE

To summarize the accuracy of diagnostic tests for CS using contemporary meta-analytic techniques (hierarchical models).

DATA SOURCES

PubMed, Embase, Scopus, Web of Science, and the Cochrane Database of Systemic Reviews (inception until August 3, 2018).

STUDY SELECTION

Studies performed in adults that determined the accuracy of one or more diagnostic tests: overnight 1-mg dexamethasone suppression test (DST), 2-day low-dose DST (2d DST), 24-hour urinary free cortisol (UFC), late-night salivary cortisol (LNSC), midnight serum cortisol (MSC), and the dexamethasone-suppressed CRH (dex-CRH) and desmopressin (dex-DDAVP) tests.

DATA EXTRACTION

Two authors independently extracted data and performed methodological assessments.

DATA SYNTHESIS

One hundred thirty-nine studies (14 140 participants) were included in the analysis. The respective sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio (95% confidence interval [CI]) estimates include the following: DST 98.6% (96.9%-99.4%), 90.6% (86.4%-93.6%), 10.5 (7.2-15.3), and 0.016 (0.007-0.035); 2d DST 95.3% (91.3%-97.5%), 92.8% (85.7%-96.5%), 13.2 (6.47-27.1), and 0.051 (0.027-0.095); UFC 94.0% (91.6%-95.7%), 93.0% (89.0%-95.5%), 13.3 (8.47-21.0), and 0.065 (0.046-0.092); LNSC 95.8% (93.%-97.2%), 93.4% (90.7%-95.4%), 14.6 (10.3-20.7), and 0.045 (0.030-0.066); MSC 96.1% (93.5%-97.6%), 93.2% (88.1%-96.3%), 14.2 (7.96-25.2), and 0.042 (0.026-0.069); and dex-CRH 98.6% (90.4%-99.8%), 85.9% (67.6%-94.7%), 7.0 (2.80-17.6), and 0.016 (0.002-0.118). A single study evaluated dex-DDAVP. Meta-regression and a novel network meta-analytic approach suggest that DST is the most sensitive while UFC is the least sensitive.

CONCLUSIONS

All of the included diagnostic tests for CS are highly sensitive and specific. It appears that the DST is the most sensitive while the UFC is less sensitive. The specificity of all first-line tests appears comparable.

THE MULTIFARIOUS CUSHING'S - LESSONS FROM A CASE SERIES

Endogenous Cushing's syndrome is rare, with an incidence of 0.7-2.4 per a million people a year. Clinical presentation of Cushing syndrome can be pleomorphic, and establishing diagnosis can be difficult. Early recognition and rapid control of hypercortisolaemia are necessary to decrease morbidity and mortality in these patients. We report a series of 6 endogenous Cushing's syndromes of different etiologies (4 Cushing's disease and 2 adrenal Cushing's syndrome) assessed in our endocrine department over a decade (2009-2019). In order to highlight the diversity of clinical forms, diagnostic tools and specific management of this condition we labelled each case suggestively: the typical Cushing's disease, the Pseudo Cushing's, the elusive Cushing's disease, the mild autonomous cortisol hypersecretion, Cushing's syndrome in pregnancy and Cushing's disease with thromboembolism. We discussed their particularities which were revelatory for the diagnosis, such as dermatologic, cardiovascular, musculoskeletal, neuropsychiatric, or reproductive signs, reviewing literature for each manifestation. We also discuss the commonalities and differences in laboratory and imagistic findings. Therapeutic approach can also differ with respect to the particular condition of each patient and the multiple choices of therapy will be reviewed.