Thyroiditis

• Thyroiditis is a group of disorders that all cause thyroidal inflammation.

• The clinical picture varies from hyper to hypothyroidism during the natural course of the disease.

Thyroiditis

Acute Subacute Chronic

Harrisons principles of internal medicine 18th edition, Dan L. Longo, Anthony S. Fauci, Mc graw hill medical publications, pp 2927-2950.

-Hashomoto’s Thyroiditis-Subacute Thyroiditis-Riedle’s Thyroiditis-Pregnancy Induced Thyroiditis-Palpation induced Thyroiditis-Radiation induced Thyroiditis-Acute/Infectious thyroiditis-Drug induced Thyroiditis.

Hashimoto's 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)

• The most common cause of thyroiditis.• This condition is the most common cause of

hypothyroidism in the United States in individuals older than 6 years.

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

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

• 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.

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.

Clinical Features• 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.

DD

• Euthyroid Sick Syndrome• Goiter• Goiter, Diffuse Toxic• Goiter, Lithium-Induced• Goiter, Nontoxic• Goiter, Toxic Nodular• Hypopituitarism (Panhypopituitarism)• Polyglandular

Autoimmune Syndrome, Type I• Polyglandular

Autoimmune Syndrome, Type II• Thyroid Lymphoma

Special investigations

• TSH•  Thyroid autoantibodies-anti-TPO and anti-Tg,• FNAC• Histology- diffuse lymphocytic and plasma cell

infiltration with formation of lymphoid follicles from follicular hyperplasia

• - Damage to the follicular basement membrane. • -Atrophy of the thyroid parenchyma

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.

“de Quervain thyroiditis”.

• Self limited disease

• CAUSE:

Possible viral cause.

• CLINICAL FEATURES:

Enlarged Gland, Tender thyrotoxicosis followed by hypothyroidism.

Over Active Phase:

• Within the first one to four months• This phase can be characterized by :

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

D/Ds

• Acute hemorrhage into a thyroid cyst, nodule, or neoplasm

• Infectious thyroiditis• Radiation-induced thyroiditis• Trauma- or palpation-induced thyroiditis• Riedel or fibroid thyroiditis• Graves thyrotoxicosis• Toxic thyroid adenoma• Toxic multinodular goiter• Acute suppurative thyroiditis

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.

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.

Riedel’s Thyroiditis• Rare disease • Replacement of the normal

thyroid parenchyma by a dense fibrosis.

• Painless goiter “woody”• Open biopsy often needed to

diagnose• Associated with focal sclerosis

syndromes.Harrisons principles of internal medicine 18th edition, Dan L. Longo, Anthony S. Fauci, Mc graw hill medical publications, pp 2927-2950.

Clinical features

• nonpainful, rapidly growing thyroid mass

Differential Diagnoses

• De Quervain Thyroiditis• Goiter• Hashimoto Thyroiditis• Thyroid Lymphoma• Anaplastic Carcinoma• Thyroiditis, Subacute

complications

• Because of the encroachment beyond the thyroid capsule, nonthyroid problems can be associated with RT. Complications of Riedel thyroiditis can include the following:

• Airway obstruction• Dysphonia• Hoarseness - Due to recurrent laryngeal involvement• Hypothyroidism• Hypoparathyroidism• Dysphagia• Stridor - Due to tracheal compression

Treatment

• Pharmacologic therapy includes the use of corticosteroids, tamoxifen, and levothyroxine.

Surgerry

• . A wedge resection of the thyroid isthmus

• Surgery is indicated when tissue is needed for diagnosis, medical treatment shows no benefit, or compressive symptoms are very severe

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.

Acute/Infectious thyroiditis

• Acute 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.

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.

MCQ

• 1.Following are seen in subacute thyroiditis except--(AIIMS-1991)

• (a) Raised ESR• (b) Raised T4 levels• (c) High Radio iodine uptake• (d) pain• ANS---C

• Hashimotos thyroiditis all are true except• a)maximum incidence in children

b)neutrophilic infiltration c) pain in hyoid d)none

• ANS --A

• hashimotos thyroiditis, all are TRUE, EXCEPT

• aiims may, 1993• Neutrophilic infiltration• Maximum incidence in child • c)Pain in hyoid • d)None of the above• Ans D

• This thyroiditis is also known as "Painless thyroiditis":(MAHE 08)

• A. Subacute lymphocytic • B. Dequervain's• C. Hashimoto• D. Riedel's thyroiditis• ANS--A

• The feature of subacute thyroiditis include

a) Elevated T3 & T4 levels b) Depressed TSH levels c) Depressed RAIU

d) All of the above

• In chronic lymphocytic thyroiditis—KARNATAKA 2007

• A)Surgery is indicated in a majority of cases

A. B)Thyroid antibody estimation is useful in a few cases

• C)FNAC is the most appropriate investigation

• D)there is no role for steroid therapy in the management

• The only reason for operating in case thyroiditisis ‑• To prevent cancerous degeneration AIIMS • 86)(JIPMER79)

• A)For relief of pain in neck and ear•• B)To overcome pressure on trachea or oesophagusC)To cure the toxic reaction• D)If there is auto immune reaction

• . Most common cause of Thyroiditis is ‑

• A)Reidl's Thyroiditis• Subacute Thyroiditis• Hashimoto's Thyroiditis• Viral thyroiditis

• 'Hurthle cells' are seen in ‑

• Agranulomatous Thyroiditis• Hashimoto's Thyroiditis• Papillary carcinoma of the thyroid• Thyroglossal cyst