Thyroid Disorders

Dr. Ali Abdel-Wahab

Objectives

Upon successful completion of this lecture, students will be able to:

Recognize the clinical picture & Laboratory findings of hyperfunction and hypofunction of thyroid gland

Enumerate causes of hypofunction and hyperfunction of thyroid gland

Discuss cretinism and myxedema List the causes of thyroid enargment Discuss the Pathogenesis of grave’s disease Discuss the Morphology of noduar goiter Discuss the complication of nodular goiter Mention the types and clinical picture of

hyperparathyroidism

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

Adenoma Carcinoma

THYROID DISEASES includes(thyroid enlargement)

Thyroid hormone disturbances

Hypothyroidism Cretinism Myxedema.

Hyperthyroidism Primary thyrotoxicosis (Graves disease). Secondary thyrotoxicosis;

Complication of nodular goiter Early Hasimoto’s thyroiditis Thyroid tumor Pituitary disorders Extrathyroid thyroxin producing tumors

Thyrotoxicosis

It is a hypermetabolic state caused by High levels of free T3 and T4.

Constitutional symptoms: Skin soft, warm, and flushedHeat intolerance Excessive sweating Weight loss despite increased appetite

Manifestations Cardiovascular

Palpitations and tachycardia congestive heart failure Ocular manifestations:

Staring gaze and lid lag Proptosis in Graves disease.

GIT Hypermotility Malabsorption Diarrhea.

Thyroid storm abrupt onset of severe hyperthyroidism during stress.

Apathetic hyperthyroidism Elderly Associated disease

Hypothyroidism

Types primary; thyroid diseases Secondary; pituitary (TSH)

Clinically Cretinism

Dietary iodine deficiency is endemic; Maternal hypothyroidism

Inborn errors in metabolism Myxedema

Autoimmune Thyroid destruction, radiation, surgery

Cretinism

Hypothyroidism developing in infancy or early childhood.

Short stature, Severe mental retardation Coarse facial features Protruding tongue Umbilical hernia

Myxedema Generalized apathy Mental sluggish ( depression). Cold intolerant Often overweight Edema (Mucopolysaccharide)

Broadening and coarsening of facial features Enlargement of the tongue Deepening of the voice.

GIT Constipation.

CVS Pericardial effusions Later stages the heart is enlarged & heart failure.

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

THYROID DISEASES includes(thyroid enlargement)

Graves disease

Graves disease is the most common cause of endogenous hyperthyroidism.

Between ages of 20 and 40 Women: men = 7:1 Genetic factors

Graves triad:

Diffusely enlarged, hyper functional thyroid

Exophthalmos in 40%. Pretibial myxedema.

Pathogenesis

Autoimmune disorder Antibodies against

TSH receptor (Thyroid-stimulating antibodies) stimulation of thyroid epithelial cell.

Thyroid is diffusely enlarged Microscopically:

Hyperplastic thyroid follicles. Lymphocytes in the stroma.

Thyroiditis:1. Autoimmune

Grave’s diseases

Hashimoto's Thyroiditis 2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

THYROID DISEASES includes(thyroid enlargement)

hashimoto's thyroiditis

Autoimmune destruction of the thyroid gland. Between 45 and 65 years, children may be

affected. Women: men 10 : 1 to 20 :

Morphology

Diffusely and symmetrically enlarged thyroid

lymphocytes, plasma cells, and well-developed germinal centers (red arrow).

The thyroid follicles are atrophic with Hürthle metaplasia (green arrow).

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

THYROID DISEASES includes(thyroid enlargement)

Subacute Granulomatous Thyroiditis

A self-limited a viral disease Characterized by granuloma formation of the

thyroid .

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3.Reidel thyroditis4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

THYROID DISEASES includes(thyroid enlargement)

Reidel thyroditis

Rare disease of the thyroid characterized by diffuse fibrosis

Thyroid become hard and adherent to the surrounding structures

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency Neoplasms

THYROID DISEASES includes(thyroid enlargement)

Types of nodular Goiter

Endemic goiter; areas where the soil, water, and food supply contain little iodine.

>10% of the population affected by goiter

Sporadic goiter occurs less commonly Females A peak incidence in puberty or young adult life Causes

Relative iodine deficiency ingestion of substances that interfere with thyroid hormone

synthesis Excessive calcium Diet; cabbage, cauliflower Contaminated water

Morphology

Three stages (forms)1. Diffuse goiter

2. Colloid goiter

3. Multinodular goiter.

Pathogenesis

Impairment of thyroxin synthesis leads to A compensatory rise in the serum TSH,

TSH causes hypertrophy and hyperplasia of thyroid A euthyroid metabolic state in the majority of individuals The compensatory responses may be inadequate; goitrous

hypothyroidism., disorder is severe The degree of thyroid enlargement is proportional to

the level and duration of thyroid hormone deficiency.

Clinically

Enlarged thyroid gland Compression

Airway obstruction Dysphagia Compression of large vessels in the neck and

upper thorax. Thyroxin level

Euthyroid Toxic goiter a minority Hypothyroidism.

Thyroiditis:1. Autoimmune

Grave’s diseases Hashimoto's Thyroiditis

2. Subacute (Granulomatous) Thyroiditis

3. Reidel thyroditis

4. Infectious thyroditis (acute and chronic)

Nodular Goiter; iodine deficiency

Neoplasms Adenoma Carcinoma

THYROID DISEASES includes(thyroid enlargement)

Tumors of the thyroid

Adenoma Carcinoma

Papillary carcinoma Follicular carcinoma. Medullary carcinoma.

Causes of thyroid carcinoma

Ionizing radiation first 2 decades of life radiation therapy 9% Among atomic bomb survivors in Japan nuclear plant disaster; Chernobyl.

Long-standing multinodular goiter.

Types of thyroid carcinoma

1. Papillary thyroid carcinoma; common, young, lymphatic spread

2. Follicular carcinoma; adult, blood spread, bone.

3. Medullary carcinoma; parafollicular cell, secrete calcitonin.

Hyperparathyroidism

Primary; parathyroid hyperplasia or adenoma, carcinoma

Secondary; chronic renal insufficiency.

Hyperparathyroidism

Effects Osteoclast activation. Increased resorption of calcium by the renal tubules Increased urinary excretion of phosphates Increased synthesis of active vitamin D The net result is an elevation in serum calcium, which,

under normal circumstances, inhibits further PTH production.