The human chorionic gonadotropin molecule from patients with trophoblastic diseases has a high thyrotropic activity but is less active in the ovary

Metastatic choriocarcinoma in a young woman presenting as thyroid storm: a case report

Background

Thyroid storm is an endocrine emergency and life-threatening condition discovered in 1926. There is no specific laboratory parameter that can differentiate or distinguish between thyroid storm and primary hyperthyroidism. Diagnosis is made on a clinical scoring system, including the Burch–Wartofsky point scale and Japanese Thyroid Association scoring system. The management is early diagnosis, immediate initiation of anti-thyroid medications, intensive care monitoring, and prevention of multiorgan failure.

Case presentation

A 30-year-old Pakistani female presented with complaint of headache, vomiting, and generalized weakness for 3 weeks. She had an episode of seizure-like activity at home, and so was rushed to the emergency department. A detailed thyroid examination revealed a soft, nontender gland with no enlargement or bruit and no exophthalmos. Her thyroid-stimulating hormone was extremely low, with high free triiodothyronine and thyroxine. Thyroglobulin was 425 ng/ml (normal reference range ≤ 55 ng/ml), and thyroid-stimulating hormone receptor antibody was 0.87 IU/L (normal reference range 0–1.75 IU/L). She had high levels of beta-human chorionic gonadotropin hormone on initial presentation. Transvaginal ultrasound showed no intrauterine pregnancy, but an echogenic focus was found adherent to the right ovary with no vascularity. With the chief complaint of headache, she underwent magnetic resonance imaging of the brain that showed multiple scattered hemorrhagic lesions in supratentorial and infratentorial brain parenchyma that were highly suspicious for metastases. Computed tomography scan of the chest, abdomen, and pelvis revealed multiple neoplastic lesions in the lung, liver, spleen, and kidneys. A Tru-Cut liver biopsy showed linear cores of liver tissue with metastatic carcinoma with morphological features consistent with choriocarcinoma. Our patient scored 65 on the Burch–Wartofsky point scale. As per the Japanese Thyroid Association scoring system, our patient met the criteria for a “definite thyroid storm.” She had initiated propranolol to achieve adequate control of her heart rate and dexamethasone. Carbimazole was started to control her thyroid function. Her thyroid function after 2 weeks of treatment showed significant improvement. Methotrexate and etoposide were given for choriocarcinoma. She made a good recovery and was discharged home. She will undergo rehabilitation along with ongoing chemotherapy (methotrexate and etoposide weekly till beta-human chorionic gonadotropin levels normalize). Unless her source of beta-human chorionic gonadotropin is carefully under control, she will continue to take anti-thyroid medications.

Conclusion

Choriocarcinoma is not only associated with hyperthyroidism but can induce thyroid storm. Beta-human chorionic gonadotropin is directly associated with promoting thyroid dysfunction. Patients with gestational trophoblastic disease should be under close surveillance to prevent thyroid storms.

Hyperthyroidism in gestational trophoblastic disease - a literature review

OBJECTIVE

Gestational trophoblastic disease (GTD) is a group of pregnancy-related disorders that arise from abnormal proliferation of placental trophoblast. Some patients with GTD develop hyperthyroidism, a rare but potentially life-threatening complication requiring early detection and management. Existing literature on hyperthyroidism in GTD is scant. This review aims to analyse the epidemiology, pathophysiology and management of this phenomenon.

METHODS

A comprehensive search of MEDLINE, EMBASE and Cochrane Library was performed to obtain articles that explored hyperthyroidism in GTD. A total of 405 articles were screened and 228 articles were considered for full-text review. We selected articles that explored epidemiology, pathophysiology and outcomes/management of hyperthyroidism in GTD.

RESULTS

The pathophysiology of hyperthyroidism in GTD is well-investigated. Placental trophoblastic tissue secretes excessive hCG, which is structurally similar to thyroid stimulating hormone and also has enhanced thyrotropic activity compared to normal hCG. The incidence and prevalence of hyperthyroidism in GTD varies worldwide, with lower rates associated with high uptake of early antenatal screening and early GTD detection. No clear risk factors for hyperthyroidism in GTD were identified. While hyperthyroidism can be definitively managed with surgical evacuation of the uterus, severe complications associated with hyperthyroidism in GTD have been reported, including thyroid storm-induced multi-organ failure, ARDS, and pulmonary hypertension.

CONCLUSION

Early detection of GTD is critical to prevent development of hyperthyroidism and its associated complications. Hyperthyroidism should be recognised as an important perioperative consideration for women undergoing surgery for GTD, and requires appropriate management. Future studies should explore risk factors for hyperthyroidism in GTD, which may facilitate earlier identification of high-risk women.

Pitfalls in the assessment of gestational transient thyrotoxicosis

Gestational transient thyrotoxicosis (GTT) is associated with direct stimulation of the maternal thyroid gland by human chorionic gonadotropin (hCG). It is characterized by slightly higher thyroid hormone and lower thyroid-stimulating hormone (TSH) levels in early pregnancy and mild or no symptoms. While GTT must be distinguished from Graves' disease (GD), which is associated with maternal and fetal complications, treated GD and new-onset GD in pregnancy are occasionally challenging to distinguish. Evaluating serum hCG levels and TSH receptor antibody (TRAb) titers can help, but the results are not irrefutable due to pregnancy-related immunosuppression. Moreover, GTT can follow unusual clinical courses in relation to some pregnancy complications. Excessive hCG production can cause severe GTT symptoms in patients with hyperemesis gravidarum, trophoblastic disease, or multiple pregnancies. Thyrotoxicosis can emerge beyond the second trimester in patients with gestational diabetes mellitus and mirror syndrome, because of delayed elevations in the hCG levels. Detailed knowledge about GTT is necessary for correct diagnoses and its appropriate management. This review focuses on the diagnosis of GTT, and, particularly, its differentiation from GD, and unusual clinical conditions associated with GTT that require comprehensive management.

Delivery of Euthyroid Baby following Hyperthyroidism in Twin Gestation with Coexisting Complete Hydatidiform Mole

Context

Gestational trophoblastic disease (GTD) is a rare complication of pregnancy, ranging from molar pregnancy to choriocarcinoma. Twin pregnancies with GTD and coexisting normal fetus are extremely rare with an estimated incidence of 1 case per 22,000–100,000 pregnancies. Molecular mimicry between human chorionic gonadotrophin (hCG) and thyroid-stimulating hormone (TSH) leads to gestational trophoblastic hyperthyroidism (GTH) which is further associated with increased maternal and fetal complications. This is the first reported case in literature describing the delivery of a baby with biochemical euthyroid status following a twin pregnancy with hydatidiform mole (HM) associated with gestational trophoblastic hyperthyroidism (GTH).

Case Description

A 24-year-old G4 P3 Caucasian female with twin gestation was admitted to hospital for gestation trophoblastic hyperthyroidism. She was later diagnosed to have twin pregnancy with complete mole and coexisting normal fetus complicated by gestational trophoblastic hyperthyroidism (GTH). Despite the risk associated with the continuation of molar pregnancy, per patient request, pregnancy was continued till viability of the fetus. The patient underwent cesarean section due to worsening preeclampsia and delivered a euthyroid baby at the 24th week of gestation.

Conclusions

Twin pregnancy with gestational trophoblastic disease and coexisting normal fetus is associated with high risk of hyperthyroidism, and careful monitoring of the thyroid function test along with dose titration of thionamides is of utmost importance throughout the gestation. If normal thyroid hormone levels are maintained during the pregnancy, euthyroidism could be successfully achieved in the baby.

Homeostatic Control of the Thyroid-Pituitary Axis: Perspectives for Diagnosis and Treatment

The long-held concept of a proportional negative feedback control between the thyroid and pituitary glands requires reconsideration in the light of more recent studies. Homeostatic equilibria depend on dynamic inter-relationships between thyroid hormones and pituitary thyrotropin (TSH). They display a high degree of individuality, thyroid-state-related hierarchy, and adaptive conditionality. Molecular mechanisms involve multiple feedback loops on several levels of organization, different time scales, and varying conditions of their optimum operation, including a proposed feedforward motif. This supports the concept of a dampened response and multistep regulation, making the interactions between TSH, FT4, and FT3 situational and mathematically more complex. As a homeostatically integrated parameter, TSH becomes neither normatively fixed nor a precise marker of euthyroidism. This is exemplified by the therapeutic situation with l-thyroxine (l-T4) where TSH levels defined for optimum health may not apply equivalently during treatment. In particular, an FT3-FT4 dissociation, discernible FT3-TSH disjoint, and conversion inefficiency have been recognized in l-T4-treated athyreotic patients. In addition to regulating T4 production, TSH appears to play an essential role in maintaining T3 homeostasis by directly controlling deiodinase activity. While still allowing for tissue-specific variation, this questions the currently assumed independence of the local T3 supply. Rather it integrates peripheral and central elements into an overarching control system. On l-T4 treatment, altered equilibria have been shown to give rise to lower circulating FT3 concentrations in the presence of normal serum TSH. While data on T3 in tissues are largely lacking in humans, rodent models suggest that the disequilibria may reflect widespread T3 deficiencies at the tissue level in various organs. As a consequence, the use of TSH, valuable though it is in many situations, should be scaled back to a supporting role that is more representative of its conditional interplay with peripheral thyroid hormones. This reopens the debate on the measurement of free thyroid hormones and encourages the identification of suitable biomarkers. Homeostatic principles conjoin all thyroid parameters into an adaptive context, demanding a more flexible interpretation in the accurate diagnosis and treatment of thyroid dysfunction.

TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis

This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range.

Hyperthyroidism and human chorionic gonadotrophin production in gestational trophoblastic disease

Background:

Gestational trophoblastic disease (GTD) is a rare complication of pregnancy, ranging from molar pregnancy to choriocarcinoma. Patients with persistent disease require treatment with chemotherapy. For the vast majority, prognosis is excellent. Occasionally, GTD is complicated by hyperthyroidism, which may require treatment. This is thought to occur due to molecular mimicry between human chorionic gonadotrophin (HCG) and thyroid-stimulating hormone (TSH), and hence cross-reactivity with the TSH receptor. Hyperthyroidism usually resolves as the GTD is successfully treated and correspondingly HCG levels normalise.

Methods:

This paper reviews cases of GTD treated over a 5-year period at one of the three UK centres and identifies the prevalence of hyperthyroidism in this population. Four cases with clinical hyperthyroidism are discussed.

Results:

On review of the 196 patients with gestational trophoblastic neoplasia treated with chemotherapy in Sheffield since 2005, 14 (7%) had biochemical hyperthyroidism. Of these, four had evidence of clinical hyperthyroidism.

Conclusion:

Concomitant biochemical thyroid disease in patients with GTD is relatively common, and measurement of thyroid function in patients with persistent GTD is, therefore, important. The development of hyperthyroidism is largely influenced by the level of HCG and disease burden, and usually settles with treatment of the persistent GTD. However, rarely the thyroid stimulation can have potentially life-threatening consequences.

Serum human chorionic gonadotropin concentrations greater than 400,000 IU/L are invariably associated with suppressed serum thyrotropin concentrations

BACKGROUND

During pregnancy, when human chorionic gonadotropin (hCG) concentrations are highest, there is a transient suppression of serum thyrotropin (TSH). In normal pregnancy, TSH concentrations generally remain within nonpregnant reference intervals; however, in some patients TSH is suppressed. Here we sought to extend previous studies to examine the relationship between very high serum concentrations of hCG (>200,000 IU/L) and the thyroid hormones TSH and free thyroxine (FT(4)). The objective of this study was to determine: 1) if there is an hCG concentration above which TSH concentrations are suppressed (< or =0.2 microIU/mL); 2) how thyroid hormone concentrations change in response to changes in hCG concentrations; and 3) the clinical symptoms in patients with such extremely elevated hCG concentrations.

METHODS

Residual specimens sent to the laboratories for physician-ordered hCG testing were utilized. Over 26 months, 15,597 physician-ordered hCG tests were performed. Sixty-nine specimens from 63 women with hCG concentrations >200,000 IU/L were identified, and TSH and FT(4) concentrations were measured. Medical records were reviewed for clinical information.

RESULTS

Thirty-seven percent of subjects had hyperemesis gravidarum (HG) and 19% had gestational trophoblastic disease (GTD). TSH was suppressed (< or =0.2 microIU/mL) in 67% of the specimens with hCG concentrations >200,000 IU/L and 100% of specimens with hCG concentrations >400,000 IU/L. FT(4) concentrations were elevated above the reference interval (1.8 ng/dL) in 32% of specimens with hCG concentrations >200,000 IU/L and in 80% of specimens with hCG concentrations >400,000 IU/L. Only four subjects had documented signs of hyperthyroidism. Women with GTD had a median hCG concentration twofold higher than women with HG and a median TSH concentration one half that of women with HG.

CONCLUSIONS

1) At hCG concentrations >400,000 IU/L, TSH is consistently suppressed; 2) serum FT(4) and TSH respond to changes in serum hCG concentrations; and 3) most patients with hCG concentrations >200,000 IU/L lack overt hyperthyroid symptoms.

Thyreotropic effect of human Chorionic Gonadotropin (hCG) in mares at estrus

The beta-subunits of thyroid stimulating hormone (TSH) and human chorionic gonadotropin (hCG) share a high homology, just like the ectodomains of their receptors, do. As a consequence, hCG was shown to exert a thyrotropic action in humans and hamsters. This study aimed to investigate whether hCG, used to induce ovulation, displays a thyrotropic effect in the equine species too. Forty mares at estrus were divided in two groups; 20 were intravenously treated with sterile saline solution (NaCl 0.9%) (group A); 20 were intravenously treated with 4000 I.U. of hCG (group B). All the mares were artificially inseminated 24 hours after the administration of the drugs and underwent blood collection at estrus detection (T1), 2, 6, 24 hours later (T2, T3, T4), and 3 and 6 days later (T5, T6), in order to detect serum fT3 and fT4 concentrations. fT3 concentrations gave rise to similar and constant trends in the two groups, without any statistically significant difference, whereas fT4 concentrations declined in both groups, remaining statistically higher in group B than in group A for 48 hours (p < 0.05), thus accounting for a thyrotropic effect of hCG. Pregnancy rate was 70% in group B and 40% in group A, respectively. The higher success in the outcome of pregnancy may result from the immunomodulating and steroidogenic effects of hCG and from the higher levels of thyroid hormones observed in the hCG treated group.

Gestational trophoblastic tumor with liver metastasis after misoprostol abortion

BACKGROUND

Early elective medical abortion is performed frequently in different countries of the world. Serious complications like gestational trophoblastic neoplasia (GTN) are uncommon and mostly nonmetastatic. High risk metastatic GTN following medical abortion is a rare event which may occur coincidentally.

CASE

A 26 year-old-woman, gravida 2 para 1, 6 weeks after misoprostol abortion presented with sever nausea, vomiting, and right upper abdominal pain. Human chorionic gonadotropin (hCG) level was 2,500,000 mIU/ml and metastatic work up revealed multiple liver metastases. She totally received nine cycles of EMA-CO (ethoposide- methotrexate- actinomycin- cyclophosphamide, vincristine) regimen for treatment and consolidation. Six months after treatment she is in complete remission.

CONCLUSION

Follow up of patients after medical abortion by means of single serum hCG measurement is highly recommended for early diagnosis of complications including gestational trophoblastic tumor. EMA-CO regimen seems to be an effective and safe treatment for liver metastatic gestational trophoblastic neoplasia.

Complete hydatidiform mole in a perimenopausal woman with a subsequent severe thyriotoxicosis

INTRODUCTION

Gestational trophoblastic disease is one form of abnormal pregnancy, with a median maternal age of 27-28 years. One complication of trophoblastic disease is the development of a secondary hyperthyroidism, which resolves rapidly after evacuation of the hydatidiform mole.

CASE REPORT

We report a case of a 53-year-old woman presenting with a complete hydatidiform mole and who developed a severe thyrotoxicosis after suction evacuation of the hydatidiform mole.

CONCLUSION

A severe thyriotoxicosis can occur even after surgical evacuation of the mole. Therefore, evaluation of the thyroid function prior to operation, especially with a high quantitative hCG, should be performed to avoid severe complications.

Significance of low thyroid-stimulating hormone in pregnancy

PURPOSE OF REVIEW

To describe the significance of low thyroid-stimulating hormone in pregnancy.

RECENT FINDINGS

Interpretation of thyroid function in pregnancy must be seen in the context of changes in thyroid economy associated with gestation. Improvements in thyroid-stimulating hormone assay methodology have resulted in accurate identification of low and suppressed thyroid-stimulating hormone in pregnancy, and recent studies of screening thyroid function in pregnancy have found an incidence of low thyroid-stimulating hormone in up to 18% of women. Normative gestational-related reference ranges for thyroid hormones, particularly thyroid-stimulating hormone and thyroxine, should be established to identify the higher as well as the lower limits of these analytes. The adverse obstetric and neonatal outcomes associated with hyperthyroidism due to Graves' disease mean that this must be differentiated from the more common cause of suppressed thyroid-stimulating hormone, i.e. gestational transient thyrotoxicosis. It is suggested that estimation of thyroid peroxidase antibodies may be a useful initial diagnostic strategy in the evaluation of women with a low or suppressed thyroid-stimulating hormone.

SUMMARY

In addition to identifying women with high thyroid-stimulating hormone levels at screening (with implications for child intelligence), establishing the cause of low thyroid-stimulating hormone will improve obstetric outcome in a number of pregnant women.

Severe hyperthyroidism requiring therapeutic plasmapheresis in a patient with hydatidiform mole

A 38-year-old woman had a 4-week history of vaginal bleeding, heat intolerance and palpitations. Levels of beta-human chorionic gonadotropin and thyroid hormones were abnormally high. After ultrasound diagnosis of a molar pregnancy, evacuation of the mole was planned with preoperative treatment involving the use of antithyroid drugs and plasmapheresis. Plasmapheresis was used to prepare for surgery in our patient who needed more rapid hormonal control. In conclusion, early diagnosis of molar pregnancy results in decreased incidence of significant complications related to hyperthyroidism.

Thyroid disorders in pregnancy

PURPOSE OF REVIEW

There is now increasing understanding of the association between not only overt, but also subclinical, thyroid disorders and dysfunction with adverse reproductive outcome. In particular, hypothyroidism and thyroid autoimmunity disorders have been shown to have both short- and long-term consequences on mother and child. An updated review is merited to revise many of the traditional views on thyroid disorders in pregnancy.

RECENT FINDINGS

Thyroid disorders constitute the commonest group of pre-gestational endocrine disorders found in pregnant women. In mothers taking antithyroid medications, breastfeeding is considered safe. The relatively high prevalence of hypothyroidism, especially subclinical hypothyroidism, the significance of screening and treatment, and the roles of iodine insufficiency and thyroid antibodies on the outcome of pregnancy and long-term neurological development of the offspring have been documented. In hypothyroid women, the dose of thyroxine replacement often needs to be adjusted from as early as the first trimester to maintain an adequate circulating thyroxine concentration.

SUMMARY

Apart from overt hyperthyroidism and hypothyroidism diagnosed before and during pregnancy, biochemical abnormalities or evidence of thyroid autoimmunity in clinically euthyroid women can affect both obstetric outcome and long-term neurological development of the offspring. Screening for thyroid function and autoimmunity, and timely and appropriate treatment, will improve pregnancy outcome. The thyroid function of infants born to mothers with thyroid disorders should also be assessed as serial monitoring and treatment may be necessary.

Prenatal diagnosis and management of twin pregnancies complicated by a co-existing molar pregnancy

Recent advances in ultrasound and molecular genetics have increased our understanding and hence enhanced the perinatal management of complete and partial hydatidiform mole. By contrast, the management of a twin pregnancy combining a normal pregnancy with a normal fetus and a complete hydatidiform mole (CHM) remains complex and controversial due to conflicting data from different parts of the world. The aim of this review is to analyse the international literature on twin pregnancies that include a mole, present the complications and outcome of pregnancy and to discuss the perinatal management. Management is complicated and women should be counselled about the maternal and fetal complications, and the pregnancy monitored carefully by a perinatal team with experience in high-risk obstetrics and access to neonatal care. The data reviewed here suggest that a woman who decides to continue with the pregnancy including a CHM must be aware that, overall, she only has a one in four chance of live birth and in around 35% of cases she will develop persistent trophoblastic disease (PTD) after delivery. In ongoing pregnancies, there will be, in at least 20% of the cases, an early onset of pre-eclampsia (PET) and a 29% risk of fetal loss due to late miscarriage, intrauterine death and neonatal death. Maternal serum human chorionic gonadotrophin (MShCG) could be useful in predicting outcome in twin pregnancy combining normal pregnancy and CHM, but this needs to be investigated prospectively.