Thyroid Gland Disorders 3

Question 2

what is Thyroiditis?

what causes it?

what can it result in?

Answer 2

Inflammation of thyroid gland.

1. Microbial pathogens
2. Autoimmune diseases

Hypothyroidism

Question 3

what are the Thyroiditis types?

Answer 3

1. Hashimoto’s thyroiditis ****
2. Subacute granulomatous thyroiditis** (de Quervain’s thyroiditis)
3. Reidel’s thyroiditis**
4. Acute thyroiditis
5. Subacute painless thyroiditis

Question 4

what is another name for hashimotos?

with what gene is it associated?

what is hashimotos?

Answer 4

autoimmune thyroiditis

HLA-DR5

Immune destruction of thyroid gland causing Initial thyrotoxicosis (due to follicle damage and release of preformed hormone) and eventual hypothyroidism.

Question 5

what is the pathogenesis of hashimotos?

Answer 5

The immune system reacts against a variety of thyroid antigens.

resulting in:

• Destruction of thyroid gland by
  
  • Cytotoxic T cells
  • Anti-thyroid cell antibodies
• Blocking ab formed against TSH receptors
  
  • Decrease hormone synthesis
• Other antibodies that are formed:
  
  • Anti thyroglobulin ab, anti thyroid peroxidase ab and anti-microsomal ab.

Question 6

what are Clinical findings of hashimotos?

Answer 6

• Painless enlargement of thyroid gland
• Initial thyrotoxicosis from gland destruction
  
  • Called Hashitoxicosis
• Eventual progression to Hypothyroidism.

Question 7

what cancer can occur with Hashimoto’s thyroiditis?

how does it present?

Answer 7

Increased incidence of Non Hodgkins B cell lymphoma of thyroid (NHL – B cell type)

• Presents as enlarging thyroid gland late in disease course.

Question 8

what are the gross findings in hashimotos?

what are the micro findings in hashimotos?

Answer 8

Firm, Pale gray to yellow enlarged thyroid .

Intense lymphocytic infiltrate with germinal centers (simulating a lymphnode).

Question 9

what are the Laboratory findings for hashimotos?

Answer 9

• High TSH, Low T4 and T3 (Those of hypothyroidism)
• Presence of anti thyroid peroxidase antibody* and anti-thyroglobulin* and antimicrosomal abs*.

Question 10

what is the Treatment for hashimoto?

Answer 10

Replace with L-thyroxine (analog of T4)

Question 11

How do you acquire Subacute granulomatous thyroiditis (de Quervain’s thyroiditis)??

Answer 11

follows a viral infection (often URTI e.g.Coxsackie).

Question 12

how does Subacute granulomatous thyroiditis (de Quervain’s thyroiditis) present?

Answer 12

Presents as tender thyroid gland** with transient hyperthyroidism**

Most common cause of painful thyroid gland*.

Question 13

how does the thyroid gland look grossly in de quervains thyroiditis?

Answer 13

enlarged and painful

Question 14

what are the micro findings in de quervains thyroiditis?

Answer 14

Granulomatous inflammation* with multinucleated giant cells

Question 15

what is the Prognosis for de quervains thyroiditis?

Answer 15

transient hypothyroidism

Question 16

what is Reidel’s thyroiditis?

Answer 16

Chronic inflammation with Fibrous tissue replacement of thyroid gland that can extend to trachea and esophagus.

Question 17

what are the Clinical features of reidel’s thyroiditis?

Answer 17

• Irregular, hard (woody consistency) thyroid gland adherent to surrounding structures.
• Can present with dyspnea or dysphagia.
• May mimic anaplastic carcinoma of thyroid
  
  • But patients are younger (40s) and malignant cells are absent

Question 18

why does Acute thyroiditis happen?

what are the clinical findings?

Answer 18

usually due to bacterial infection

• Fever
• Tender and enlarged thyroid with
• Cervical lymphadenopathy
• Neutrophilic leukocytosis
• Signs of Thyrotoxicosis due to gland destruction (resolves after treatment of infection)

Question 19

who gets Subacute painless lymphocytic thyroiditis?

Answer 19

patients receiving:

Amiodarone, interferon alpha (for Hepetitis C) or IL-2

Question 20

what are the Clinical findings in Subacute painless lymphocytic thyroiditis?

Answer 20

• Minimally enlarged thyroid
• No pain

Question 21

what are the micro findings in Subacute painless lymphocytic thyroiditis?

what happens if inflammation persists?

Answer 21

Lymphocytic infiltrate without germinal centers

if inflammation persists hypothyroidism may develop

Question 22

what is Goiter?

Answer 22

Generalized enlargement of thyroid gland in a euthyroid individual that does not result from inflammatory or neoplastic process.

Question 23

why does goiter result in enlargement of the thyroid?

Answer 23

due to impaired synthesis of thyroid hormone ( due to iodine deficiency).

Question 24

what are the 2 types of goiter?

Answer 24

1. Diffuse nontoxic (simple) goiter
2. Multinodular goiter.

Question 25

what is Diffuse nontoxic (Simple) goiter?

what is another name for this?

Answer 25

enlargement without nodularity

Colloid goiter

Question 26

what are the 2 types of diffuse non-toxic goiter?

Answer 26

1) endemic:

• Associated with iodide deficiency
• In areas with low iodine (Alps, Andes and Himalayas)

2) sporadic
* Associated with diets rich in goitrogens, puberty, pregnancy.

Question 27

what is a characteristic finding in diffuse nontoxic goiter?

Answer 27

multinodular goiter and you will see hyperplasia and hypertrophy in the thyroid

Question 28

what is the clinical course of diffuse nontoxic goiter?

Answer 28

• Vast majority euthyroid****
• S/S due to mass effect**.

Question 29

what are the complications of multinodular goiter?

Answer 29

Complications:

1. Hemorrhage into cyst** : sudden painful gland enlargement
2. Hoarseness: compression of laryngeal nerve
3. Dyspnea and stridor: compression of trachea
4. Toxic nodular goiter: one or more nodule becomes TSH independent leading to increased T3 and T4 release and causing Thyrotoxicosis.