POST PARTUM SILENT THYROIDITIS: causes, symptoms and therapy

There postpartum silent thyroiditis o post-pregnancy thyroiditis is an inflammatory disease affecting the thyroid gland, which manifests itself by 2 to 18 months after giving birth, and it affects one woman every 20 after pregnancy. It usually manifests itself with a initial hyperthyroidism followed by a phase of hypothyroidism and, normally, with a normal resumption of the secretory function of the thyroid. Only a small fraction of affected women remain hypothyroid permanently. The therapy is different depending on the time of the disease (suppressive and symptomatic therapy in the stages of thyrotoxicosis, replacement therapy with levothyroxine in the stage of hypothyroidism).

What is postpartum silent thyroiditis?

There postpartum thyroiditis and silent or painless thyroiditis are nowadays considered to be manifestations of the same clinical entity, and are distinguished only by the moment in which they occur. Postpartum thyroiditis is a silent thyroiditis that develops after one pregnancy, usually two months to one and a half years after delivery, although it usually occurs within 6 months of delivery. Silent thyroiditis is also called painless thyroiditis, occult subacute thyroiditis, hyperthyroiditis, lymphocytic thyroiditis with hyperthyroidism, or transient hyperthyroidism with lymphocytic thyroiditis.

Silent thyroiditis has a prevalence of 4% in the general population (i.e. 4 out of 100 people will suffer from it during their lifetime) and postpartum a prevalence of 5-10% in women who have given birth at least once.

Causes of postpartum silent thyroiditis

What is postpartum thyroiditis caused by? What are the triggers? This type of thyroiditis is considered an atypical form of autoimmune thyroid disorder. It is believed that the main risk factors are partly linked to genetic causes, and partly secondary to environmental factors. From the histological point of view under the microscope the finding of lymphocytic thyroiditis is observed with the presence of T lymphocyte infiltrates.

Symptoms and clinical course of postpartum silent thyroiditis.

Women with postpartum silent thyroiditis show a fluctuating course with an initial phase of hyperthyroidism, followed by a period with thyroid normofunction, which then results in a more or less marked picture of hypothyroidism.

In thyrotoxic phase early the size of the thyroid may slightly increase secondary to intense tissue inflammation, dimensions which will then increase further in the hypothyroid phase due to the stimulating action of TSH, which will be increased to try to compensate for the reduced concentration of thyroid hormones.

THE symptoms of postpartum silent thyroiditis in the stage of thyrotoxicosis will therefore be those of hyperthyroidism:

  • tachycardia,
  • tremors,
  • sweats,
  • slimming,
  • irritability,
  • diarrhea.

In this phase there is no ocular pathology (ophthalmopathy), as opposed to hyperthyroidism secondary to Basedow-Graves disease.

In the next stage of hypothyroidism Classical symptoms of thyroid hypofunction are observed, although usually of lesser entity than those present in chronic hypothyroidism, such as:

  • asthenia,
  • constipation,
  • weight gain,
  • cold intolerance,
  • edema in the lower limbs,
  • tendency to depression (which often worsens pre-existing postpartum depression).
Postpartum silent thyroiditis.

Silent postpartum thyroiditis: thyroid disease that occurs after pregnancy.

Diagnosis of postpartum silent thyroiditis

How do you recognize a postpartum silent thyroiditis? The diagnosis is purely clinical and biohumoral. From the physical examination and recent medical history you will learn signs and symptoms of hyperthyroidism (or hypothyroidism, if evaluation is late), there will be an increase in the volume of the thyroid gland (painless diffuse goiter). The blood tests that will confirm the diagnosis or not are TSH and the thyroid hormones fT3 and fT4. In the first phase we will therefore have low TSH and high fT3 and Ft4, while in the late phase we will have high TSH and low thyroid hormones.

When assayed, the elevated anti-thyroid anti-Tg and anti-TPO antibodies will be elevated in most cases, with anti-TSH receptor (anti-TSH-R) antibodies normal. Precisely the absence of anti-TSH receptor antibodies makes it possible to make a differential diagnosis with hyperthyroidism from Graves' disease, together with the short duration of the hyperthyroid stage (usually less than 3-4 months) with the reduced uptake of radioiodine and reduced serum T3 / T4 ratio (less than 20). Differential diagnosis with De Quervain's subacute thyroiditis is facilitated by the absence of pain on palpation of the thyroid.

Therapy of postpartum silent thyroiditis

How to care there postpartum silent thyroiditis? Since the stage of thyrotoxicosis is usually mild, short-lived and self-limiting, often no other therapy is needed than a beta blocker to reduce the symptoms of hyperthyroidism. Only rarely is it necessary to also use drugs suppressants thyroid hormones such as methimazole or propityluracil. When hypothyroidism develops, i.e. in over 50% of women, it is necessary to administer L-T4 instead (levothyroxine, better known trade names Eutirox or Tirosint) which is suspended after 6 months, in order to understand if in the meantime the thyroid has recovered its normal function or not.

Since 20% of patients with postpartum thyroiditis and the 50% of patients with silent thyroiditis undergo prolonged hypothyroidism, it is essential to undergo periodic biohumoral checks with dosage of thyrotropin (TSH), free thyroxine (fT4), antibodies to thyroglobulin and anti-thyroperoxidase every 6 months for the first 2 years, then TSH and fT4 control every 12 months.

Prognosis of postpartum silent thyroiditis

There prognosis in this type of disease it is very good, since in most cases the thyroid dysfunction is only temporary. Even if the hypothyroidism phase is not transient but permanent, taking an adequate replacement therapy leads to a substantially normal life expectancy.


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