Endocrinology Made Simple : Post partum thyroidits

Post partum thyroidits

This condition occurs in females in the post partum period

It affects about 5% of all women.

It Is caused by autoimmunity and has a triphasic course.

First Phase

In first phase,there is phase of thyrotoxicosis in the first few weeks after delivery with a characteristic low radioactive iodine uptake

Second Phase

The second phase is called hypothyroid phase in which there is  hypothyroidism that’s lasts for upto a few months

Women in this phase experience low energy, poor memory, impaired concentration, carelessness, dry skin, cold intolerance, and general aches and pains

Third and final phase is phase of recovery:

80 % of patients recover in post partum thyroiditis.

Pathophysiology

During pregnancy, immunologic suppression occurs which induces tolerance to the presence of the fetus.

Without this suppression, the fetus would be rejected causing miscarriage.

As a result, following delivery, the immune system rebounds causing levels of thyroids antibodies to rise in susceptible women.

Specifically, the immunohistological features of susceptible women are indicated by:

Antibodies to thyroglobulin (TgAb)

Antibodies to thyroid peroxidase (TPOAb)

Increase in TPOAb subclasses IgG1-IgG3

Lymphocyte infiltration and follicle formation within thyroid gland (Hashimoto's thyroiditis)

T-cell changes (increased CD4:CD8 ratio)

TSH-receptor antibodies (TSH-R Abs)

Differential diagnosis:

Subacute hypothyroidism:

This is usually follows a viral infection

The recovery rate is 100 %

The thyroid gland is extremely tender

Hashimotos Thyroiditis:

It usually presents with hypothyroidism and goitre.

There is a high titre of anti-TPO antibodies.

During pregnancy, T3 and T4 levels are elevated due to increased levels of thyroid binding globulin induced by estrogens.

In the post partum period,T4 and T 3 levels return to normal.

Free thyroid hormones Free T3 and T4 and TSH return to normal range during pregnancy and post partum period.

Treatment

For most women, the hyperthyroid phase presents with very mild symptoms or is asypmtomatic; intervention is usually not required.

If symptomatic cases require treatment, a short course of beta-blockers would be effective.

Assessing treatment for the hypothyroid is more complex. Women with symptoms or a very high TSH level, or both, are usually prescribed a course of levothyroxine.

Asymptomatic women with slightly elevated TSH levels who are planning subsequent pregnancies, should consider a course of treatment until completion of the family to avoid possible developmental complications in future children.

Otherwise, treatment could be discontinued after 1 year postpartum.