Three-dimensional sonography in the evaluation and management of fetal goiter

Current knowledge about the in utero and peripartum management of fetal goiter associated with maternal Graves' disease

Maternal Graves’ disease is the most common cause of fetal goiter. Fetal goiter can cause complications attributable either to the physical effects of the goiter itself or to thyroid dysfunction, which can be life-threatening and cause neurological impairment. Determining whether a goiter is caused by fetal hyperthyroidism or hypothyroidism is the main clinical problem, and in utero evaluations and management are essential. Ultrasonography combined with color Doppler and magnetic resonance imaging are helpful for the initial diagnosis and monitoring, but these imaging techniques have a limited ability to discriminate between fetal hyperthyroidism and hypothyroidism. To determine the fetal thyroid status, fetal blood sampling using cordocentesis is reliable but hazardous, and the indications must be considered carefully. Amniocentesis is an easier and safer alternative, but the correlations between the amniotic fluid and fetal serum thyroid hormone levels remain unclear. If a fetal goiter is accompanied by hypothyroidism, administering thyroid hormone intra-amniotically may be effective and relatively safe. However, the wide variety of approaches to treatment exemplifies the lack of guidelines, and no systematic studies have been conducted to date. Therefore, intrauterine treatment should be reserved for selected patients at a high risk of complications. Moreover, when intrauterine treatment fails and a fetal goiter can cause airway obstruction, intrapartum management, such as ex utero intrapartum treatment, may be required; however, reports describing the use of this procedure for fetal goiter are limited. This review summarizes the current knowledge about fetal goiter associated with maternal Graves’ disease and evaluates the most significant new findings regarding its in utero and peripartum management.

Fetal goitrous hypothyroidism treated by intra-amniotic levothyroxine administration: case report and review of the literature

BACKGROUND

Fetal goitrous hypothyroidism is mainly caused by maternal treatment of Graves' disease. Fetal goiter sometimes compresses the trachea and esophagus and may cause polyhydramnios, preterm labor, complications of labor and delivery, and neonatal respiratory disorder.

CASE PRESENTATION

We report a case of fetal goitrous hypothyroidism in which the mother had Graves' disease, which was treated with propylthiouracil. Intra-amniotic levothyroxine (L-T4) administration was performed, and the fetal goiter decreased in size. A female infant was delivered without goiter and complications. Thyroid function was within the normal range.

CONCLUSIONS

Previous reports on fetal goitrous hypothyroidism that was treated with intra-amniotic L-T4 showed that patients who had intra-amniotic L-T4 administration were likely to have a good outcome compared with patients who did not have L-T4. Thyroid function of the mother and fetus should be carefully monitored and treated appropriately.

Intra-amniotic thyroxine to treat fetal goiter

A 35-year-old pregnant woman visited our department and had been treated with 100 µg of daily oral levothyroxine for hypothyroidism. An ultrasonography screening was performed at 25 weeks gestation and revealed a fetal goiter and an increased amniotic fluid volume. Fetal hypothyroidism was confirmed by cordocentesis and amniotic hormone levels at 26 weeks gestation. We treated the mother with 200 µg of daily oral levothyroxine to optimize the transplacental transfer. A total of four intra-amniotic injections of levothyroxine were administered, resulting in progressive reduction in the fetal thyroid volume of goiter as measured by 3D ultrasonography and increased amniotic fluid volume. Following birth, neonatal serum thyroid stimulating hormone level was within the normal range, but free T4 was reduced. Based on this case, we suggest that monitoring amniotic fluid thyroid hormone concentration and intra-amniotic levothyroxine injection can be used to reduce the thyroid volume of goiters and to prevent polyhydramnios.

Antenatal diagnosis and treatment of hypothyroid fetal goiter in an euthyroid mother: a case report and review of literature

Fetal goiter is an extremely rare complication of pregnancy. Its incidence is 1 in 40,000 deliveries. Antithyroid maternal therapy is responsible for 10-15% of fetal congenital hypothyroidism and can be considered as the most frequent underlying cause for this condition. The frequency of fetal goiter that is associated with fetal hypothyroidism and normal maternal thyroid function, as in our case, is even less frequent. Fetal goiter is associated with increased rate of perinatal complications and long-term morbidity, due to peripartum complications including labor dystocia due to its mass effect, as well as neonatal airway obstruction that may lead to hypoxic-ischemic brain injury and death. We present, in this study, a case report of late antenatal fetal goiter in an euthyroid woman and a literature review of the diagnosis and treatment of these cases.

Antithyroid drug-induced fetal goitrous hypothyroidism

Maternal overtreatment with antithyroid drugs can induce fetal goitrous hypothyroidism. This condition can have a critical effect on pregnancy outcome, as well as on fetal growth and neurological development. The purpose of this Review is to clarify if and how fetal goitrous hypothyroidism can be prevented, and how to react when prevention has failed. Understanding the importance of pregnancy-related changes in maternal thyroid status when treating a pregnant woman is crucial to preventing fetal goitrous hypothyroidism. Maternal levels of free T(4) are the most consistent indication of maternal and fetal thyroid status. In patients with fetal goitrous hypothyroidism, intra-amniotic levothyroxine injections improve fetal outcome. The best way to avoid maternal overtreatment with antithyroid drugs is to monitor closely the maternal thyroid status, especially estimates of free T(4) levels.

Advantages and disadvantages of 3D ultrasound of thyroid nodules including thin slice volume rendering

BACKGROUND

The purpose of this study was to assess the advantages and disadvantages of 3D gray-scale and power Doppler ultrasound, including thin slice volume rendering (TSVR), applied for evaluation of thyroid nodules.

METHODS

The retrospective evaluation by two observers of volumes of 71 thyroid nodules (55 benign, 16 cancers) was performed using a new TSVR technique. Dedicated 4D ultrasound scanner with an automatic 6-12 MHz 4D probe was used. Statistical analysis was performed with Stata v. 8.2.

RESULTS

Multiple logistic regression analysis demonstrated that independent risk factors of thyroid cancers identified by 3D ultrasound include: (a) ill-defined borders of the nodule on MPR presentation, (b) a lobulated shape of the nodule in the c-plane and (c) a density of central vessels in the nodule within the minimal or maximal ranges. Combination of features provided sensitivity 100% and specificity 60-69% for thyroid cancer.Calcification/microcalcification-like echogenic foci on 3D ultrasound proved not to be a risk factor of thyroid cancer.Storage of the 3D data of the whole nodules enabled subsequent evaluation of new parameters and with new rendering algorithms.

CONCLUSIONS

Our results indicate that 3D ultrasound is a practical and reproducible method for the evaluation of thyroid nodules. 3D ultrasound stores volumes comprising the whole lesion or organ. Future detailed evaluations of the data are possible, looking for features that were not fully appreciated at the time of collection or applying new algorithms for volume rendering in order to gain important information. Three-dimensional ultrasound data could be included in thyroid cancer databases. Further multicenter large scale studies are warranted.

Use of 3-dimensional sonography for prenatal evaluation and follow-up of fetal goitrous hypothyroidism

OBJECTIVE

Fetal goitrous hypothyroidism is a rare and potentially lethal condition. Consequently, its early diagnosis and treatment improve prognosis. Thyroid hormone measurement in either fetal serum or amniotic fluid implies important risks. Here we present a fetal goiter and the follow-up procedure, both done by the traditional method and by using 3-dimensional power Doppler (3DPD) imaging and virtual organ computer-aided analysis (VOCAL).

METHODS

A single well-documented case of fetal goiter was followed weekly from 22 weeks until delivery. Amniocentesis for thyrotropin (TSH) and free thyroxine (T(4)) measurement as well as levothyroxine injections were performed at every control. In addition to amniocentesis, every control involved a sonographic evaluation, which included standard measurements of the gland and the capture of volume image sets in gray scale and 3DPD. Volume calculation of the gland was done using VOCAL software. Vascularization of the gland was evaluated by the vascularization index (VI) included in the software.

RESULTS

With treatment, TSH levels decreased progressively until normalization. Free T(4) levels increased toward the end of gestation. Sonographic measurements of the gland volume to estimated fetal weight ratio decreased across treatment as levels of TSH did. The VI clearly depicted the vascular regression of the goiter, decreasing throughout treatment in a consistent way until 24 hours before delivery.

CONCLUSIONS

Gray scale and 3DPD evaluations of the thyroid gland have been validated under similar circumstances and might be reliable complements to the invasive methods used in the management of this fetal condition.

Use of ultrasound to distinguish between fetal hyperthyroidism and hypothyroidism on discovery of a goiter

OBJECTIVES

To determine whether sonography can be used to distinguish hyperthyroidism from hypothyroidism in pregnancies with fetal goiter.

METHODS

This was a retrospective study of 39 cases of fetal goiter. The majority of the mothers had Graves' disease. Fetuses were scanned for the existence of a hypertrophic thyroid gland (goiter) beginning at 22 gestational weeks. Once a goiter was diagnosed, different echographic features were analyzed and the effect of chosen treatment on fetal thyroid development was monitored.

RESULTS

On color Doppler, 68.8% of hypothyroid goiters had a peripheral vascular pattern vs. 20% in cases of fetal hyperthyroidism (P = 0.0574). No hypothyroid goiter presented central vascularization whereas half the hyperthyroid goiters did (P = 0.0013). Fetal tachycardia was a good indicator of hyperthyroidism (57.1% v.s 6.3%; P = 0.0055). Delayed bone maturation was seen in hypothyroid goiters (46.9% vs. 0%; P = 0.0307), while advanced bone maturity was specific to hyperthyroid goiters (85.7% vs. 0%; P < 0.0001). Lastly, an increase in fetal movement was observed in cases of fetal hypothyroidism (43.8% vs. 0%; P = 0.0364).

CONCLUSION

Based on the color Doppler pattern of goiter, fetal heart rate, bone maturation and fetal mobility, we established an ultrasound score to predict fetal thyroid function in cases of fetal goiter.

Goitrous congenital hypothyroidism in a twin pregnancy causing respiratory obstruction at birth: implications for management

We report a twin pregnancy complicated by fetal goitrous hypothyroidism secondary to dyshormonogenesis caused by thyroglobulin deficiency. Antenatal treatment with intra-amniotic thyroxine was considered but not performed, given the late gestational age at diagnosis and the multiple nature of the pregnancy. Both twins developed airway obstruction at delivery, requiring intubation and ventilation. We review the literature and describe the practical issues relating to the antenatal assessment and perinatal management of fetal goitre.