Thyroiditis

Ahmed Adel Fouad Abdelhakeem

WHAT IS THYROIDITIS ?

Thyroiditis is a general term that refers to “inflammation of the thyroid gland”.

Thyroiditis includes a group of individual disorders that all cause thyroidal inflammation and, as a result, causes many different clinical presentations.

The Types of Thyroiditis

Hashimoto’s

thyroiditis

Subacute thyroiditi

s

Acute/Infectious thyroiditis

Drug-induced

thyroiditis

Radiation induced

Thyroiditis

HASHIMOTO'S THYROIDITIS

The most common cause of thyroiditis.

This form of thyroid disease may also be referred to as chronic lymphocytic thyroiditis.

It is characterized by:

Gradual thyroid failure because of autoimmune destruction of the thyroid gland.

The name Hashimoto thyroiditis is derived from the 1912 report by Hashimoto describing patients with goiter and intense lymphocytic infiltration of the thyroid (struma lymphomatosa)

INCIDENCE:

it is primarily a disease of older women.

can occur in children “ nonendemic goiter”

The concordance rate in monozygotic twins is 30% to 60%.

Several chromosomal abnormalities have been associated with thyroid autoimmunity.

There are reports that polymorphisms in the HLA locus, specifically the HLA-DR3 and HLA-DR5 alleles, are linked to Hashimoto thyroiditis, but the association is weak.

genome wide linkage analyses in families with Hashimoto thyroiditis have provided evidence for several susceptibility loci, such as on chromosomes 6p and 12q, that may harbor genes predisposing to this disorder.

Pathogenesis

PATHOGENESIS Hashimoto thyroiditis is an autoimmune

disease in which the immune system reacts against a variety of thyroid antigens.

There is progressive depletion of thyroid epithelial cells (thyrocytes), which are gradually replaced by mononuclear cell infiltration and fibrosis.

THE EFFECTOR MECHANISMS FOR THYROCYTE DEATH:

Morphology

MORPHOLOGY The thyroid is often diffusely enlarged.

The capsule is intact.

the gland is well demarcated from adjacent structures.

The cut surface is pale, yellow-tan, firm, and somewhat nodular.

Morphology

MICROSCOPIC EXAMINATION

THE SYMPTOMS: many of the symptoms associated with

thyroid hormone deficiency. Fatigue Drowsiness Difficulty with learning Dry, brittle hair and nails Dry, itchy skin Puffy face Constipation. Weight gain Heavy menstrual flow Increased frequency of miscarriages Increased sensitivity to many medications.

SUBACUTE THYROIDITIS is a self-limited thyroid condition.

associated with a triphasic clinical course of hyperthyroidism, hypothyroidism, and return to normal thyroid function.

responsible for 15-20% of patients presenting with thyrotoxicosis.

and 10% of patients presenting with hypothyroidism.

IN GENERAL, THE FOLLOWING 3 FORMS OF SUBACUTE THYROIDITIS ARE RECOGNIZED

Subacute granulomatous,

subacute painful, or “de Quervain thyroiditis .”

Lymphocytic thyroiditis (also known as subacute

painless thyroiditis).

Subacute postpartum thyroiditis.

Subacute granulomatous thyroiditis

Self limited disease

CAUSE:

Possible viral cause.

CLINICAL FEATURES:

Enlarged Gland, Tender thyrotoxicosis followed by hypothyroidism.

MICROSCOPIC: Infiltration of chronic inflammatory cells. Foreign Body giant cells “ Giant Cell Thyroiditis “

LYMPHOCYTIC THYROIDITIS

Self limited disease

CAUSE:

Anti-thyroid antibodies, autoimmune disease

CLINICAL FEATURES:

Thyrotoxicosis followed by hypothyroidism.

MICROSCOPIC: Non-Specific lymphoid infiltration of thyroid parenchyma. No germinal center formation.

MICROSCOPIC:

POST-PARTUM THYROIDITIS

This is the type of thyroiditis that may occur in women after they give birth.

2 Phases:

Over Active Phase.

Under Active Phase.

Then, return to Normal state.

OVER ACTIVE PHASE: Within the first one to four months after

delivery. This phase can be characterized by :

1. slight enlargement of the thyroid .2. Anxiety.3. Restlessness.4. Insomnia.5. weight loss.6. difficulty concentrating.

DIAGNOSIS: blood tests to measure : increased levels of thyroid hormone in

the bloodstream . the abnormal antibodies, anti-

microsomal and antithyroglobulin antibodies.

A fine needle aspiration biopsy of the thyroid gland during this phase would reveal inflammatory cells attacking the thyroid gland.

TREATMENT: During this hyperthyroid phase,

treatment is usually not recommended because this phase usually lasts for a short period of time, about 2 to 4 months.

However, if the symptoms are extreme, beta blockers may be used to slow the heart rate and decrease nervousness.

UNDER ACTIVE PHASE: occurs 3 to 8 months postpartum. This phase can be characterized by:

1. slight enlargement of the thyroid gland.

2. weight gain.3. Fatigue.4. lack of energy .5. depression.

TREATMENT thyroid hormone medication for about

six months. After this time, the medication is

stopped to determine whether or not the thyroid has recovered its normal function.

If so, the medication may be stopped permanently, otherwise the medication must be resumed because of permanent injury to the thyroid gland.

ACUTE/INFECTIOUS THYROIDITIS

cute suppurative thyroiditis is quite rare in modern times.

Cause: It is caused by a bacterial infection in

the thyroid which causes pus to collect and form an abscess within the thyroid gland.

The bacterial infection may be carried in the bloodstream from anywhere in the body or it may come from the throat itself.

SYMPTOMS thyroidal pain. systemic illness. painless enlargement of the thyroid. hypothyroidism. The symptoms usually resolve once the

infection resolves. In the few instances where it still occurs,

antibiotics and surgery to drain the pus can result in complete cure.

DRUG-INDUCED THYROIDITIS

CAUSE: Drugs include: amiodarone, lithium,

interferons, cytokines.

CLINICAL FEATURES: Either thyrotoxicosis or hypothyroidism.

DURATION AND RESOLUTION: Often continues as long as the drug is

taken.

RADIATION INDUCED THYROIDITIS

CAUSE:1. Follows treatment with radioactive iodine

for hyperthyroidism 2. external beam radiation therapy for

certain cancers.

CLINICAL FEATURES:3. Occasionally thyrotoxicosis4. more frequently hypothyroidism.

Thyrotoxicosis is transient

hypothyroidism is usually permanent

DURATION AND RESOLUTION

TREATMENT OF THYROIDITIS Treatment depends on the type of

thyroiditis and the clinical presentation.

Thyrotoxicosis

Hypothyroidism

Thyroidal pain

THYROTOXICOSIS

Beta blockers to decrease palpitations and reduce shakes and tremors may be helpful.

HYPOTHYROIDISM

thyroid hormone replacement.

THYROIDAL PAIN anti-inflamatory medications such as

aspirin . steroid therapy with prednisone.