b17m03l08 Thyroid Nodules

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    THYROID NODULE BLOCK XV

    Dr. F Hilado MODULE III10/30/2015 3:00-5:00 PM LECTURE VI

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    OUTLINE

    I. Thyroid Gland Anatomy

    II. Thyroid Nodules

    III.

    Diagnostic Evaluation Methods- History and PE

    - Laboratory Tests

    - Investigative Procedures

    IV. Differential Diagnosis

    V. Diagnostic Approach

    VI. Thyroid cancer

    THYROID GLAND ANATOMY

    Largest endocrine gland in the body and is tasked with

    regulating the metabolism of most of the bodys cells

    Butterfly-shaped organ located inferior to the larynxand over the 2

    ndand 3

    rdcricoid cartilage.

    It has two pyramidal-shaped lateral lobes,

    approximately 5 cm long, joined by the narrow

    isthmus anterior to the trachea

    Pretracheal fascia

    - Attaches the thyroid to the trachea so that

    it moves with the trachea and larynx when

    swallowing but not when the tongue is

    protruded

    THYROID NODULES

    Goiter- Is an enlarged thyroid gland by palpation,

    ultrasound, or thyroid scan

    It is not about the blood tests. This will only tell you

    the function, whether it is hypothyroid, hyperthyroid,

    or euthyroid

    GOITER

    - refers to an enlarged thyroid gland

    - Biosynthetic defects, iodine deficiency, autoimmune

    disease, and nodular diseases can each lead to goiteralthough by different mechanisms

    Biosynthetic defects and iodine deficiency

    - reduced efficiency of thyroid hormone synthesis,

    leading to increased TSH, which stimulates thyroid

    growth as a compensatory mechanism to overcome the

    block in hormone synthesis.

    Graves disease

    -the goiter results mainly from the TSH-Rmediated

    effects of TSI

    Hashimotos thyroiditis

    -

    occurs because of acquired defects in hormone

    synthesis, leading to elevated levels of TSH and its

    consequent growth effects.

    - Lymphocytic infiltration and immune systeminduced

    growth factors also contribute to thyroid enlargement

    in Hashimotos thyroiditis.

    NODULAR DISEASE

    - is characterized by the disordered growth of thyroid

    cells, often combined with the gradual development of

    fibrosis- occurring in about 37% of adults when assessed by

    physical examination

    Ultrasound: nodules are present in up to 50% of adults,

    with the majority being

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    Diagnostic evaluation:

    A case of single thyroid nodule. A 25-year-old patient with

    incidental ultrasound finding of a thyroid nodule in the left

    lobe

    (a) Thyroid ultrasoundshows a solid hypoechoic nodule,

    with microcalcifications

    (b) Thyroid scintigraphyshows the cold nodule with no

    detectable 99mTcO4 uptake. The patient underwent fine

    needle cytology and the cytology was suspicious forpapillary carcinoma

    Imaging In Endocrinology

    MULTINODULAR

    Diagnostic evaluation:

    A case of multinodular toxic thyroid. A hyperthyroid 46-

    year-old woman with a palpable multinodular thyroid.

    (a) Ultrasound scanshows an enlarged thyroid with

    multiple nodules in both right and left lobe. The gland

    seems to extend in the mediastinum

    (b) Thyroid scintigraphy.The scan shows intense uptake in

    the glandular parenchyma with multiple cold areas in

    correspondence to the major nodules seen at ultrasound.

    This finding is consistent with the diagnosis of a

    multinodular toxic thyroid. The patient underwent

    surgery

    Imaging In Endocrinology

    Nodular, non-toxic goiter

    - 1 nodule, blood tests are normal

    Nodular, toxic goiter:- 1 nodule with abnormal blood tests

    - TSH low with T3 and T4 that is high

    Diffuse goiter:

    - enlarged thyroid but no nodules

    Multinodular:

    - >2 nodules either toxic or non-toxic

    There is no nodular hypothyroid or multinodular

    hypothyroid, we call that non-toxic hypothyroid

    DIAGNOSTIC EVALUATION METHODS

    HISTORY TAKINGWhen we see a nodule, what are we going to do?

    What are we going to ask?

    HISTORY TAKING PHYSICAL EXAMINATION

    Is it painful?

    History of fever, cough,

    nasal congestion, fluids

    one month ago?

    Does it go with

    swallowing?

    For how long did he

    notice the nodule?

    Family history of

    thyroid nodule or

    thyroid cancer?

    Weight loss/gain?

    Sleeping patterns?

    Tremors?

    Palpitations?

    Inspection:

    Allow to swallow (does it

    follow?)

    Palpation:

    Tender? How many? Size?

    Auscultation:

    bruit (present in Graves

    disease, but not in nodules)

    History

    Benign disease

    - Family history of Hashimotos thyroiditis, benign

    thyroid nodule, or goiter

    -

    Symptoms of hypothyroidism or hyperthyroidism; an

    a sudden increase in size of the nodule

    with pain or tenderness, which suggests a cyst or

    localized subacute thyroiditis

    Malignancy

    - include young age (60 years

    - male gender

    - history of external neck irradiation during childhood

    - more than 1 nodule

    - it can be cystic,

    complex, solid

    -

    toxic, non-toxic and

    euthyroid

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    adolescence

    - rapid growth

    - recent changes in speaking, breathing, or swallowing;

    and a family history of

    thyroid cancer or multiple endocrine neoplasia type 2

    (MEN2)

    Physical Examination

    Malignancy- firm consistency of the nodule

    - irregular shape

    - fixation to underlying or overlying tissues

    - vocal cord paralysis

    - Suspicious regional lymphadenopathy

    Nodule Size < 4 cm

    - not predictive of malignancy

    -

    the incidence of cancer in incidentally identified or

    nonpalpable thyroid nodules is the same as in patients

    with palpable

    nodulesNodule Size >4 cm

    - the incidence of carcinoma may be higher

    Williams Textbook of Endocrinology

    Laboratory Tests

    Serum TSH

    - first-line screening test,

    - may be measured with a highly sensitive immunometric

    assay and combined with a single measurement of free

    thyroid hormone concentrations

    Low or undetectable serum TSH

    - associated with normal thyroid hormones suggest

    possibility of toxic, autonomously functioning

    nodular areas in the goiter and should lead to

    thyroid scintigraphy

    - indicates the need to monitor the patient for the

    possible development of hyperthyroidism and

    indicates that there is no point in attempting further

    suppression of TSH with thyroxine therapy

    High serum TSH value

    - Patients with thyroid cancer

    -

    even if it is within the upper part of the referencerange, is associated with increased risk of

    malignancy in a thyroid nodule

    - indicates hypothyroidism and suggests Hashimoto

    thyroiditis

    Antithyroid Peroxidase Antibodies

    - helpful in the diagnosis of chronic autoimmune

    thyroiditis, especially if serum TSH is elevated

    Serum Thyroglobulin levels

    - The measurement of serum thyroglobulin levels h

    historically not been recommended in the

    evaluation of solitary thyroid nodule because it is

    also elevated in benign thyroid disorders

    - There is more recent data to suggest that elevated

    serum thyroglobulin, thyroglobulin antibody, and

    thyroid-stimulating hormone (TSH) levels may be

    associated with a higher risk of malignancy

    Williams Textbook of Endocrinolo

    Investigative Procedures

    A number of investigative techniques identify possible

    malignancy of the nodule, including imaging with

    radionuclide, ultrasound examination, and fine needle

    biopsy

    RADIOISOTOPE SCANNING

    Scintigraphy

    - is the standard method for functional imaging of the

    thyroid.

    - The two isotopes most commonly used are 123I and

    99mTc pertechnetate, the latter being the agent of

    choice, because of lower cost and greater availability

    Interpretation

    - Scanning provides a measure of the iodine-trapping

    function in a nodule compared

    with the surrounding thyroid tissue.

    -

    Normally, there is uniform tracer uptakethroughout both lobes and sometimes even in the

    isthmus

    On the basis of tracer uptake:

    NORMAL

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    Cold Warm Hot

    Hypofunctioni

    ng

    Indeterminate Hyperfunctioning

    Decreased

    uptake

    Uptake similar

    to surrounding

    tissue

    increased nodular

    uptake with

    suppression of uptake

    in the surrounding

    tissue80-85% 10 %

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    CT SCAN AND MRI

    - Limited role in the initial evaluation of solitary thyroid

    nodule

    - Indications for these imaging techniques include

    suspected tracheal involvement, either by invasion or

    compression, extension into the mediastinum, or

    recurrent disease

    FNA BIOPSY- This procedure represents a major advance in the

    diagnosis and management of thyroid nodules

    - now considered the most effective test currently

    available to distinguish benign from malignant thyroid

    nodules

    - diagnostic accuracy that approaches 95%

    FNA BIOPSY RESULT

    Benign Diagnosis Malignant Diagnosis

    Colloid Nodule

    Cyst

    Lymphocytic ThyroiditisGranulomatous Thyroidit