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Classification of thyroid diseases

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Classification of thyroid diseases Enlargement of the gland Goiters Tumors Hyperthyroidism Graves disease Toxic multinodular goiter Toxic adenoma Hypothyroidism ... – PowerPoint PPT presentation

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Title: Classification of thyroid diseases


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Classification of thyroid diseases
  • Enlargement of the gland
  • Goiters
  • Tumors
  • Hyperthyroidism
  • Graves disease
  • Toxic multinodular goiter
  • Toxic adenoma
  • Hypothyroidism
  • Hashimoto thyroiditis
  • Suabcute thyroiditis
  • Riedel thyroiditis
  • Congenital Cretinism

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Enlargement of the gland
  • Goiters
  • Non toxic goiter
  • Diffuse non toxic goiter
  • Multinodular goiter
  • Thyroid cancer

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Goiters
  • Goiter an overgrown of the thyroid gland
    usually seen as a swelling in the neck.
  • The swelling may be linked to hyperthyroidism,
    hypothyroidism or normal levels of thyroid
    function
  • There are many types of goiters
  • Non toxic goiter
  • Diffuse goiters
  • Multinodular non toxic goiters
  • Multinodular toxic goiter included under
    hyperthyroidism

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A. Non toxic goiters
  • Non toxic goiters are also called simple, colloid
    or multinodular goiter.
  • It refers to an enlargement of the thyroid that
    is NOT associated with functional, inflammatory
    or neoplastic alterations ? therefore, patients
    are euthyroid
  • More common in females
  • Diffuse form of goiters presents mostly in
    adolescents and pregnancy
  • Multinodular form presents in persons older than
    50 years of age.

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A. Non toxic goiters
  • Pathogenesis
  • Patients are thought to have a subtle impairment
    of iodine utilization and to respond in an
    exaggerated fashion to normal TSH levels

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A. Non toxic goiters
  • Pathology
  • Diffuse non toxic goiter
  • Early stage of the disease
  • The gland is diffusely enlarge
  • Microscopically ? it exhibits hypertrophy and
    hyperplasia of follicular epithelial cells

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Non toxic goiters
  • Pathology
  • Multinodular non toxic goiter
  • Evolves as the disease becomes more chronic
  • Many patients develop TOXIC multinodular goiters
  • The enlarged gland assumes an increasingly
    nodular configuration
  • Microscopically,
  • The nodules vary in size and shape.Some are
    distended with colloid and others are collapsed
  • Lining epithelial cells are flat to cuboidal and
    are arrayed as papillae that project into
    follicular lumen
  • Hemorrhagic, necrotic and cystic areas are common
    and fibrous band traverse the gland.

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A. Non toxic goiters
  • Clinical features
  • Patients are asymptomatic presenting with a mass
    in the neck
  • Large goiters ? compress trachea and esophagus ?
    cause inspiratory stridor or dysphagia
  • Hoarseness result from compression pf recurrent
    laryngeal nerve
  • Thyroid function test TSH, T4, T3 normal

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A. Non toxic goiters
  • Treatment
  • Administration of thyroid hormone to reduce TSH
    levels and stimulation to thyroid growth
  • In older patients, Radioactive iodine therapy is
    indicated
  • Surgery is contraindicated unless the local
    obstructive symptoms become troublesome.

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B. Thyroid cancer
  • It is more common in females between the 30 70s
    years of age
  • Types
  • Papillary
  • Follicular
  • Medullary
  • Anaplastic undifferentatited

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B. Thyroid cancer
  • Papillary thyroid carcinoma
  • The most common thyroid cancer
  • Pathogenesis
  • Iodine excess
  • Previous radiation to the neck
  • Genetic factors such as HLA DR7
  • Pathology
  • Orphan Annie nuclei
  • Eosinophilic pseudoinclusions
  • Nuclear grooves

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Orphan Annie nucleus
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B. Thyroid cancer
  • Follicular thyroid carcinoma
  • 15 25 of all thyroid cancers
  • It could be minimally invasive or widely invasive
    ? blood borne metastasis
  • Metastasis are directed to the bones of the
    shoulder, pelvis, sternum and skull
  • Some patients present with pathological fractures
    due to metastasis
  • Treatment Radio labeled Iodine

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B. Thyroid cancer
  • Medullary thyroid carcinoma
  • Tumor derived from parafollicular or C cells
  • Less than 5 of thyroid carcinomas
  • Patients having familial form of this carcinoma
    are afflicted with MEN type 2 that includes
    pheochromocytoma of the adrenal medulla and
    parathyroid hyperplasia
  • Pathology
  • Presence of stromal amyloid which represents the
    deposition of procalcitonin

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B. Thyroid cancer
  • Anaplastic Undifferentiated thyroid carcinoma
  • Rapidly fatal
  • History of long standing goiter
  • Invasion of the soft tissues of the neck
  • Pathology
  • Sarcoma like proliferation of spindles and giant
    cells with polyploid nuclei, necrosis and stromal
    fibrosis

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Hyperthyroidism
  • Refers to the clinical consequences of excessive
    circulating thyroid hormone
  • Graves Disease
  • Toxic multinodular goiter
  • Toxic adenoma

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1. Graves Disease
  • Autoimmune disorder that is characterized by
    diffuse goiter, hyperthyroidism and exophthalmos
  • Most frequent cause of hyperthyroidism in
    patients younger than 40 years of age

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1. Graves Disease
  • Pathogenesis
  • Immune mechanism
  • Patients are hyperthyroid owing to the presence
    of IgG antibodies directed against components of
    the plasma membrane of the thyroid follicular
    epithelium presumably the TSH receptor
  • These antibodies function as an agonist they
    stimulate the TSH receptor ? activate adenyl
    cyclase ? increase in thyroid hormone secretion
  • Under continuous stimulation, the thyroid becomes
    diffusely hyperplastic and excessively vascular
  • Patients with Graves disease and their relatives
    both have a higher incidence of other autoimmune
    disease including pernicious anemia and Hashimoto
    thyroiditis

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1. Graves Disease
  • Pathogenesis
  • Sex
  • More common in females than males
  • Emotional influences
  • The onset of Graves disease often follows a
    period of emotional stress.
  • Opthalmopathy
  • Exophthalmos is a common complication of Graves
    disease
  • T lymphocytes that are sensitized to antigens
    shared by thyroid follicular cells and orbital
    fibroblasts accumulate around the eye where they
    secrete cytokines that activate fibroblasts.

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1. Graves Disease
  • Pathology
  • The thyroid is symmetrically enlarged
  • Microscopically,
  • The thyroid is diffusely hyperplastic and highly
    vascular
  • The epithelial cells are tall and columnar and
    are often arranged as papillae that project into
    the lumen of the follicles
  • The colloid tends to be depleted and presents a
    scalloped moth-eaten appearance
  • Scattered lymphocytes and plasma cells infiltrate
    the interstitial tissue

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Graves Disease
  • Clinical features
  • gradual onset of nonspecific symptoms such as
    nervousness, emotional lability, tremor, weakness
    and weight loss
  • They are intolerant of heat, and tend to sweat
    profusely
  • Almost all patients exhibit tachycardia or
    palpitations
  • Physical examination reveals
  • a symmetrically enlarged thyroid often with an
    audible bruit and palpable thrill
  • Protrusion of the eyeball and retraction of the
    eyelids expose the sclera
  • The skin is warm and moist
  • Some patients exhibit Graves dermopathy which is
    a peculiar pretibial edema caused by the
    accumulation of fluid and glycosaminoglycans

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1. Graves Disease
  • Treatment
  • antithyroid drugs
  • Radioiodine
  • adjuvant therapy with corticosteroids
  • adrenergic anatagonist

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2. Toxic Multinodular Goiter
  • Many patients who are older than 50 years of age
    develop functional autonomy of the nodules and a
    toxic form of the disease
  • More frequent in women
  • Never develop exophthalmos
  • Patients complain of cardiac complications such
    as atrial fibrillation and congestive heart
    failure
  • Serum T4 T3 are minimally elevated
  • Microscopic examination reveals groups of small
    hyperplasic follicles mixed with other nodules of
    varying size that appear to be inactive.
  • Treatment radio labeled iodine

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3. Toxic adenoma
  • A solitary hyperfunctioning follicular neoplasm
    in a normal thyroid
  • Hyperfunctioning of the adenoma suppresses the
    remainder of the thyroid which then atrophies
  • Treatment radiolabeled iodine and surgery for
    large nodules.

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Hypothyroidism
  • Refers to the clinical manifestation of the
    thyroid hormone deficiency
  • It can be the consequence of 3 general processes
  • Defective synthesis of the thyroid hormone
  • Inadequate function of the thyroid parenchyma
  • Inadequate secretion of TSH by the pituitary or
    TRH by the hypothalamus

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1. Hashimoto Thyroiditis
  • An autoimmune disease that is characterized by
    circulating antibodies to thyroid antigens and
    features that are suggestive of cell-mediated
    immunity to thyroid tissue
  • Arises most commonly in women during the 4th and
    5th decades of life
  • in regions where supplies of Iodine are adequate
    ? Hashimoto thyroiditis is the most common cause
    of goitrous hypothyroidism

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1. Hashimoto Thyroiditis
  • Pathogenesis
  • Patients exhibit high titers of circulating
    autoantibodies directed against thyroid
    peroxidase, thyroglobulin and the TSH receptor
  • The intense filtration of the thyroid parenchyma
    by lymphocytes and plasma cells suggest
    cell-mediated destruction of the gland
  • Both patients of Hashimoto and their relatives
    have a higher incidence of other autoimmune
    diseases, such as Insulin dependent diabetes
    mellitus, pernicious anemia, Addison disease, and
    myasthenia gravis
  • Hashimoto is associated with an increased
    frequency of the HLA- B8, HLA-Dr3, and HLA-DR5
    haplotypes

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1. Hashimoto Thyroidtis
  • Pathology
  • The gland in Hashimoto is diffusely enlarged,
    firm and slightly lobular
  • Microscopically, the gland displays
  • Infiltrate of lymphocytes and plasma cells
  • Destruction and atrophy of the follicles
  • Oxyphilic metaplasia of the follicular epithelial
    cells

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1. Hashimoto Thyroiditis
  • Clinical features
  • The patient notes a gradual onset of a goiter
  • Majority of these patients are euthyroid, few are
    hypothyroid when they present for medical
    attention
  • Most cases progress to a hypothyroid state
  • Many patients require no treatment
  • Thyroid hormone is administered to alleviate
    hypothyroidism and to decrease the size of the
    gland

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2. Subacute Thyroiditis
  • It is also called (DeQuervain, Granulomatous, or
    Giant cell thyroiditis)
  • Infrequent self-limited viral infection of the
    thyroid that is characterized by granulomatous
    inflammation
  • The disease typically occurs after upper
    respiratory tract infections including those
    caused by Influenza Virus, adenovirus, echovirus,
    and coxsackievirus
  • Affect women between 30 50 years of age

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2. Subacute thyroiditis
  • Pathology
  • The gland is enlarged and the cut surface is firm
    and pale
  • Microscopic examination reveals
  • An acute inflammatory reaction often with micro
    abscesses
  • Appearance of a patchy infiltrate of lymphocytes,
    plasma cells and macrophages throughout the gland
  • Numerous multinucleated giant cell of the foreign
    body type often containing colloid

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2. Subacute Thyroiditis
  • Clinical features
  • Pain in the anterior neck which is sometimes
    accompanied by fever
  • On physical examination, the thyroid is
    moderately enlarged and tender
  • Generally resolves within a few months and
    without clinical sequelae

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3. Riedel thyroiditis
  • Rare disease that is characterized by dense
    fibrosis of the thyroid
  • The disease involves extrathyroid soft tissues of
    the neck and is often associated with progressive
    fibrosis in other locations including the
    reroperitoneum, mediastinum, and orbit
  • A disease of middle age with a female male ratio
    of 31
  • Cause is unknown
  • Patients notice a gradual onset of painless
    goiter
  • Patients may suffer from the consequences of
    compression of the trachea, esophagus and
    recurrent laryngeal nerves
  • Treatment is primarily surgical to relieve
    compression of local organs

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