Postpartum thyroiditis

Introduction to postpartum thyroiditis Postpartum thyroiditis (PPT) is a thyroid dysfunction syndrome that occurs one year after birth and can be temporary or permanent. Its pathological basis is thyroid autoimmune inflammation, which is the most common and most characteristic postpartum autoimmune thyroiditis. The disease can also occur after abortion 5 to 20 weeks of pregnancy. Postpartum thyroiditis and postpartum thyroid syndrome are two different concepts. The latter refers to thyroid dysfunction that occurs after birth or is developing thyroid disease. basic knowledge The proportion of the disease: the incidence rate is about 0.001% -0.003% Susceptible population: postpartum women Mode of infection: non-infectious Complications: hypothyroidism

Causes of postpartum thyroiditis

Autoimmune (30%):

It has been shown that this disease is closely related to autoimmunity. In the early pregnancy (first 3 months), TPOAb positive patients, the incidence of postpartum thyroiditis is as high as 30% to 50%, and postpartum TPOAb levels are often suggestive of postpartum immune rebound and immune mediated. The degree of thyroid damage is severe. In recent years, it has also been noted that thyroiditis can occur within 1 year after natural or elective abortion (including ectopic pregnancy) in early pregnancy, similar to postpartum thyroiditis, and antibody-positive ones before pregnancy are more negative than antibodies. The risk of miscarriage is 2 times higher, and the in vivo immunological changes in non-term pregnancy are sufficient to cause post-production thyroiditis.

Genetics (20%):

Studies have shown that this disease has HLA antigen polymorphism. A large number of clinical and laboratory studies have also suggested that Hashimoto thyroiditis and the disease may have a common cause.

The explanation for the correlation between HLA antigen and the pathogenesis of postpartum thyroiditis may be:

(1) The disease site is not linked to the HLA site, and it is also possible that HLA plays a direct role in the disease process.

(2) The polymorphism of HLA may be an influencing factor for the ability of antigen presenting cells to present a special series of antigenic peptides, thereby modulating the susceptibility of the disease.

Dietary factors (15%):

Excessive iodine can induce postpartum thyroiditis, and hypothyroidism is most likely to occur in women with a history of the disease with a daily intake of iodine greater than their daily requirements.

Postpartum thyroiditis prevention

The use of iodine-containing drugs in women with a history of this disease should be avoided to avoid induction of hypothyroidism.

Prenatal and postnatal determination of TPO-Ab in pregnant women is of great significance in predicting the occurrence of this disease. Especially for those with positive antibodies, strict follow-up of postpartum thyroid function should be performed. Because 82.2% of patients with this disease have hormonal abnormalities at 6 months postpartum, Some researchers have suggested that the disease and high-risk groups should be followed up for 6 months and beyond.

Women with postpartum thyroiditis can regain normal thyroid function.

Postpartum thyroiditis complications Complications hypothyroidism

In patients with postpartum thyroiditis, if hypothyroidism occurs during pregnancy, it will affect the development of the fetal nervous system, resulting in a decrease in the child's IQ.

Symptoms of postpartum thyroiditis Common symptoms Postmenopausal postpartum thyroid enlargement Hyperthyroidism during gestational tachycardia Vascular murmur Weight gain Goiter fatigue mental disorder

Patients with this disease can be relapsed after pregnancy and between 2 weeks of pregnancy, the recurrence rate is 25% to 40%, this disease can occur in Sheehan syndrome postpartum.

The clinical manifestations of this disease are short-lived, sometimes ambiguous and easily overlooked.

Thyrotoxicosis: about 50% occur, 1 to 3 months after birth, can last for 1 to 2 months, of which only 22.2% of the clinical process, appetite, weight loss, neuroticism, etc. often lack specificity, However, palpitations and fatigue may be more prominent and become the main complaint of the treatment. If the thyrotoxicosis stage is more than 2 months, the symptoms are more obvious and may be accompanied by mental symptoms.

51% thyroid enlargement, manifested as goiter or increased on the original basis, mostly mild diffuse enlargement, uniform texture, occasionally only a single isolated nodule, no pressure pain, no vascular murmur, permanent There is no thyroid enlargement when sexual thyroid function declines.

Transient hypothyroidism: 25% to 42.3% only show this stage, 35.5% have experienced the above two different stages, usually 3 to 6 months postpartum symptoms: edema, weight gain, chills, loss of appetite, etc. Sometimes showing mental disorders, can be mistaken for depression, the incidence of depression in women with circulating thyroid antibody positive patients increased by 8.8% to 30%.

Some people have menopause or uterine bleeding, or menopausal-galvanic syndrome with increased PRL and misunderstanding pituitary lesions. Most patients can return to normal within 5 to 10 months after delivery.

Permanent hypothyroidism occurs in 10% to 23% of patients, and 50% of women with TPOAb-positive disease develop hypothyroidism in the future, with an annual incidence of about 3% to 5%. Patients with transient hypothyroidism in the early stage of the disease 25% to 30% of patients have permanent hypothyroidism, and 92% of those with permanent hypothyroidism have transient hypothyroidism in the early stage of the disease, and TSH>20mU/L in the early postpartum dysfunction stage. Long-term thyroid dysfunction predictive index, early pregnancy TPOAb titer is a good indicator of long-term hypothyroidism after the onset of the disease, multiple pregnancy and postpartum thyroiditis after persistent hypothyroidism is associated, the incidence of spontaneous abortion It is associated with permanent hypothyroidism; it is speculated that these patients have mild hypothyroidism during pregnancy and affect the viability of the fetus. For patients with hypothyroidism, symptoms of persistent hypothyroidism should be considered for one year. Symptoms, in the 6th month after delivery, 82% of women with this disease have hormonal abnormalities, some people are not typical After the bed, has entered the stage of hypothyroidism during treatment, patients have hyperthyroidism and hypothyroidism postpartum period not appear or appear obvious, physical examination only goiter.

The disease usually relieves itself within 1 year.

Postpartum thyroiditis check

1. White blood cells are normal, and the erythrocyte sedimentation rate (ESR) is normal or slightly elevated.

2. During the onset of hyperthyroidism, serum T3, T4 increased, TSH decreased, TSH inhibited to the lowest detectable range, and TSH stimulation could not increase it.

3. Serum TG is elevated, serum TPO-Ab level is increased, but its titer is lower than that of Hashimoto's thyroiditis. About 2/3 of patients have positive thyroid antibody, and TPO-Ab positive rate is significantly higher than TGAb. TSAb is present in the serum of a small number of patients, but the titer and time of occurrence are not related to the onset and severity of thyroid virus.

4. Thyroglobulin (Tg) can be increased, which is related to thyroid lymphocyte infiltration and gland destruction. The sensitivity to the diagnosis of this disease is 0.81 and the specificity is 0.98.

5. The thyroid gland 131I rate was significantly reduced in the thyrotoxic phase, and recovered in the low-function phase.

6. Perchlorate release test for perchlorate release test in women with normal thyroid function 2 to 4 years after postpartum thyroiditis. Most patients have positive perchlorate release test, suggesting that these women are persistent. Defects in thyroid iodine biochemistry, this defect is related to the titer of positive thyroid autoantibodies before the experiment.

7. Ultrasound examination of the thyroid can show low echo, and continuous low echo may indicate that the thyroid autoimmune destruction process persists.

8. Thyroid biopsy due to postpartum thyroiditis, the thyroid gland only slightly increased, puncture operation is difficult, generally do not do thyroid biopsy, if necessary, the results are conducive to diagnosis and differential diagnosis.

Diagnosis and differentiation of postpartum thyroiditis

This disease is very easy to miss diagnosis, for postpartum goiter or aggravation, in the past mostly attributed to simple goiter, fatigue within 1 year after delivery, tachycardia, nervousness, goiter or persistent amenorrhea, should consider this disease, especially It is a goiter during pregnancy and a patient with high titer thyroid antibody. It has a family history of autoimmune thyroid disease. The risk of developing this disease is increased after birth. It is necessary to improve the vigilance of this disease. Postpartum goiter or thyroid gland Increased sex, even if there is no functional change may be postpartum thyroiditis, prospective studies have shown that thyroid function is normal, postpartum thyroiditis accounted for 4%.

Graves disease can be aggravated or recurred after birth, exophthalmos, thyroid murmur or pre-tibial mucinous edema, thyroid iodine rate increased and different from this disease, but can coexist with the disease, if combined, the iodine uptake rate can not be used as identification For the diagnosis, the TSAb should be determined and identified by thyroid needle aspiration cytology if necessary.

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