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Thyroid Disease: Diagnosis and Management

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Thyroid Disease: Diagnosis and Management Internal Medicine Resident Lecture Series Michael Pascolini D.O. 8/18/2004 – PowerPoint PPT presentation

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Title: Thyroid Disease: Diagnosis and Management


1
Thyroid DiseaseDiagnosis and Management
  • Internal Medicine Resident Lecture Series
  • Michael Pascolini D.O.
  • 8/18/2004

2
Goal
  • The residents will understand how to diagnose and
    manage thyroid disease

3
Objectives
  • The residents will
  • understand the basic hormonal actions of the
    thyroid gland
  • evaluate and diagnose a patient with thyroid
    disease using clinical skills and lab work
  • understand the four different types of Malignant
    thyroid tumors

4
Question 1
  • In X-linked TBG deficiency, the TSH level is
  • A. increased
  • B. decreased
  • C. normal

5
Thyroid Axis
Dopamine Glucocorticoids Somatostatin
Hypothalamus
TRH
Pituitary
TSH
Thyroid
T3 and T4
6
Thyroid Axis
  • Thyroid hormones (T3 and T4) are the dominant
    regulator of TSH TRH production
  • TSH production
  • pulsatile diurnal (highest levels at night)
  • long plasma 1/2 life (50 min)

7
Iodine
  • Iodine transport is a critical first step in
    thyroid hormone synthesis
  • Normal thyroid extracts 10-25 radioactive iodine
    trace over 24 hrs.
  • Thyroid of Graves disease can extract 70-90
  • Areas of iodine deficiency have increased
    incidence of Goiter
  • Oversupply of iodine is associated with increased
    incidence of autoimmune thyroid disease
  • Decreased iodine increases thyroid bloodflow
  • Excess iodine inhibits thyroid iodide
    organification (Wolff-Chaikoff effect)

8
Thyroid hormones
  • T4 is secreted 20x in excess of T3 from thyroid
    gland
  • both are bound to plasma proteins
    thyroxine-binding thyroglobulin(TBG),
    transthyretin (TTR) and Albumin (99.98 T4 and
    99.7 T3)
  • Free T3 gt Free T4 (only free hormone is available
    to tissues)

9
Thyroid hormones
  • Homeostatic mechanisms maintain normal
    concentration of free hormones
  • X-linked TBG deficiency - There are low levels of
    total T3 T4, however free hormone levels are
    normal.
  • patients are euthyroid, TSH levels are normal
  • TBG are increased by estrogen (pregnancy,
    estrogen birth control pills) TBG, total T3 T4
    are increased. Free T3 and T4 are normal.
  • Do not try to normalize the total hormone levels

10
Question 1
  • In X-linked TBG deficiency, the TSH level is
  • A. increased
  • B. decreased
  • C. normal

11
Question 1
  • In X-linked TBG deficiency, the TSH level is
  • A. increased
  • B. decreased
  • C. normal

12
Question 2
  • Which of the following can cause a decreased TSH
    level?
  • A. severe non thyroid illness
  • B. medications (increased levels of dopamine and
    glucocorticoids)
  • C. TSH secreting pituitary tumor
  • D. Thyroid hormone resistance (increased free T4
    T3 with normal TSH)

13
Physical Exam
  • Extrathyroid features Opthalmopathy and
    Dermopathy
  • Inspect pt from front and side
  • Palpate thyroid from behind pt
  • note tenderness, fixation, nodularity, masses
  • Bruit over gland suggests increased vascularity
    (hyperthyroidism)

14
Physical Exam
15
Physical Exam
  • If low boarders are not clearly felt, pt may have
    retrosternal goiter
  • Venous distention, difficulty breathing,
    especially when arms are raised (Pembertons
    sign)
  • Central Masses - have pt stick out tongue,
    thyroglossal cysts will move upward
  • Asses lymphadenopathy in supraclavicular and
    cervical regions

16
Lab Eval
  • First determine TSH level
  • normal TSH level excludes primary abnormalities
    of thyroid function, with rare exceptions
  • Abnormal TSH, next get a free T4 and T3 resin
    uptake tests
  • Resin uptake test - compares amount of T3 bound
    to Resin as opposed to unoccupied thyroid hormone
    binding proteins
  • uptake increased when proteins are low or Thyroid
    hormone levels are increased

17
Lab Eval
  • TSH as screening test may be misleading
    (especially without Free T4)
  • Increased TSH level
  • severe non thyroid illness
  • TSH secreting pituitary tumor
  • Thyroid hormone resistance (increased free T4
    T3 with normal TSH)
  • Artifact
  • Decreased TSH level
  • 1st trimester of pregnancy (2o hCG secretion)
  • Treatment of hyperthyroidism (suppression lasts
    several weeks)
  • medications (increased levels of dopamine and
    glucocorticoids)
  • TSH should not be used to assess a patient with
    known pituitary disease.

18
Hypothyroidism - signs and symptoms (decreasing
order of frequency)
  • Signs
  • Dry coarse skin
  • Puffy face, hands and feet
  • Diffuse alopecia
  • Bradycardia
  • Peripheral edema
  • Delayed tendon reflex relaxation
  • Carpal tunnel syndrome
  • Serous cavity effusion
  • Symptoms
  • Tiredness, weakness
  • Feeling cold
  • Difficulty concentrating and poor memory
  • Constipation
  • Weight gain with poor apatite
  • Dyspnea
  • Hoarse voice
  • Menorrhagia
  • Parasthesias
  • Impaired hearing

19
Hypothyroidism
  • increased TSH and a decreased free T4
  • Congenital
  • Autoimmune
  • Iatrogenic

20
Hypothyroidism
  • Congenital
  • 1 in 3000-4000 newborns
  • lt10 are diagnosed with clinical features
  • prolonged jaundice, feeding problems, hypotonia,
    enlarged tongue, delayed bone maturation.
  • permanent neurological damage could occur if
    treatment is delayed
  • Treatment is levothyroxine at 10-15 mcg/kg/day,
    monitoring effects by TSH levels

21
Hypothyroidism
  • Autoimmune
  • may be associated with goiter (Hashimotos) or
    minimal residual thyroid tissue (atrophic
    thyroiditis), later in the disease.
  • patients present with typical signs and symptoms

22
Hypothyroidism
  • Iatrogenic
  • may be caused by radioiodide treatment (in the
    1st 3-4 months after treatment)

23
Hypothyroidism
  • Treatment
  • Start daily replacement dose of levothyroxine at
    1.5 mcg/kg of body weight
  • adjust the dose based on TSH levels
  • once replacement is achieved, annual TSH are
    recommended to follow

24
Thyrotoxicosis - signs and symptoms (decreasing
order of frequency)
  • Signs
  • Tachycardia A-fib in the elderly
  • Tremor
  • Goiter
  • Warm, moist skin
  • Muscle weakness, proximal myopathy
  • Lid retraction or lag
  • Gynecomastia
  • Symptoms
  • Hyperactivity, irritability, dysphoria
  • Heat intolerance and sweating
  • Palpitations
  • Fatigue and weakness
  • Weight loss with increased apatite
  • Diarrhea
  • Polyuria
  • Oligomenorrhea

25
Thyrotoxicosis
  • Thyrotoxicosis - the state of thyroid hormone
    excess
  • Hyperthyroidism - result of excessive thyroid
    function
  • Labs Decreased TSH and increased free T3 T4
  • Etiologies
  • Graves disease
  • Thyroiditis
  • Toxic Adenoma

26
Thyrotoxicosis
  • Graves disease
  • 60-80 of thyrotoxicosis, depending on iodine
    intake (increased intake increased prevalence)
  • Diagnosis can be excluded if TSH is normal
  • clinical features worsen without treatment
    mortality 10-30

27
Thyrotoxicosis
  • Graves disease
  • Treatment goal is to reduce thyroid hormone
    synthesis using antithyroid drugs
  • Thionamides
  • Propylthiouracil 100-200mg q 6-8 hours
  • Carbimazole 10-20 mg BID or TID
  • Methimazole 10-20 mg BID or TID

28
Thyrotoxicosis
  • Thyroiditis
  • Acute
  • pt presents in thyroid pain
  • infection of thyroid, rare, usually secondary to
    presence of piriform sinus
  • Treatment guided by Gram stain and culture of FNA
    biopsy
  • Subacute (deQuervains thyroiditis)
  • many viruses implicated as cause peak incidence
    30-50 yrs FgtM
  • Treat with relatively large doses of Aspirin or
    other NSAIDs.(600mg q4-6 hrs)

29
Thyrotoxicosis
  • Thyroiditis
  • Silent (painless thyroiditis)
  • usually pts have underlying autoimmune thyroid
    disease
  • clinical course same as subacute thyroiditis
    without the pain
  • glucocorticoids are not indicated
  • Propranolol may be used to treat sever
    thyrotoxicosis

30
Thyrotoxicosis
  • Toxic adenoma
  • autonomously functioning thyroid nodule
  • hypersecretion of T4 and T3 leads to
    thyrotoxicosis
  • etiology related to iodine deficiency
  • Always greater than 3cm in diameter
  • Labs decreased TSH and marked elevation of T3
    levels, borderline elevation of T4
  • Almost never malignant
  • May treat with antithyroid drugs but if size
    continues to increase, then surgery or I-131
    therapy

31
Sick Euthyroid Syndrome
  • Any acute, severe illness can cause abnormalities
    in TSH of thyroid hormone levels in the absence
    of underlying disease. These measurements can be
    misleading
  • Common pattern Decreased Total and Free T3 with
    normal levels of T4 and TSH

32
Amiodarone effects on Thyroid
  • Amiodarone is structurally related to thyroid
    hormone and contains 39 iodine by weight
  • increased iodine levels for gt6 months after
    discontinuation of drug
  • Multiple effects on thyroid function
  • acute, transient changes in thyroid function
  • hypothyroidism in susceptible patients with
    increased iodine
  • thyrotoxicosis, possibly by induction of
    autoimmune Graves disease

33
Question 2
  • Which of the following can cause a decreased TSH
    level?
  • A. severe non thyroid illness
  • B. medications (increased levels of dopamine and
    glucocorticoids)
  • C. TSH secreting pituitary tumor
  • D. Thyroid hormone resistance (increased free T4
    T3 with normal TSH)

34
Question 2
  • Which of the following can cause a decreased TSH
    level?
  • A. severe non thyroid illness
  • B. medications (increased levels of dopamine and
    glucocorticoids)
  • C. TSH secreting pituitary tumor
  • D. Thyroid hormone resistance (increased free T4
    T3 with normal TSH)

35
Question 3
  • Which of the following malignant tumors has the
    poorest prognosis?
  • A. Anaplastic carcinoma
  • B. Follicular (well-differentiated thyroid
    carcinomas)
  • C. Papillary
  • D. Medullary thyroid carcinoma

36
Benign lesions
  • Can be categorized into
  • nontoxic - diffuse and multinodular goiter
  • toxic - toxic multinodular goiter, solitary toxic
    adenoma, and diffuse toxic goiter (Graves
    disease)
  • inflammatory - Thyroiditis acute, subacute and
    chronic
  • Benign thyroid diseases are significant to the
    surgeon because
  • mechanical constraint on the upper aerodigestive
    structures
  • its not possible to rule out carcinoma within a
    nodular lesion of the thyroid gland

37
Malignant tumors
  • Primary epithelial tumors, they account for 1.5
    of all cancer in the US
  • Papillary
  • Follicular (well-differentiated thyroid
    carcinomas)
  • Medullary thyroid carcinoma
  • Anaplastic carcinoma

38
Papillary Adenocarcinomas
  • 80 of all thyroid carcinomas
  • incidence in the 3rd and 4th decade
  • both lobes involved in 80 of the cases often
    multicentric
  • tumor spreads by regional lymphatics to
    paratracheal or lateral cervical lymph nodes
  • locoregional metastasis is high from 37-65
  • 5-year survival rates range from 70-95 with
    mortality of 10-20 over 10-20 year period
  • significant mortality occurs from intrathyroidal
    lesions gt 5cm in diameter or extracapsular spread

39
Follicular Carcinomas
  • 10 of all thyroid cancers
  • more prevalent in areas of endemic goiter
  • occurs exclusively in patients older than 40
    years
  • Multicentricity is uncommon as is lymph node
    metastasis
  • tumor spreads by angioinvasion distant mets to
    lungs or bone in 65of patients
  • 5-year survival rate is about 70, decreasing to
    40 at 10 years.
  • if distant mets present, 5-year survival is 20

40
Medullary Thyroid Carcinoma
  • 5-7 of thyroid carcinomas
  • originate from parafollicular cells (neural crest
    cells)
  • calcified areas in the thyroid is a radiological
    feature of this tumor
  • 60-80 are sporadic cases10-40 are familial.
  • sporadic case is unilateral familial cases are
    bilateral
  • Familial cases occur in the MEN syndrome type II
  • better prognosis than the sporadic cases
  • 5- and 10-year survival rates range from 88 and
    78, respectively
  • cervical lymph node mets affects 10 year rate
    down to 46

41
Anaplastic Carcinoma
  • one of the most lethal carcinomas 1-5 of
    thyroid malignancies
  • mainly affects patients older than 65 years.
  • only small-cell type responds to radiation
    therapy
  • Approximately 10 of patients will survive 1
    year.
  • Average duration of survival after diagnosis is
    3-6 months
  • Effective treatment is rarely feasible.

42
Thyroid Ultrasound
  • Can differentiate cystic from solid thyroid
    nodules in gt80 cases
  • used increasingly in the diagnosis of thyroid
    disease
  • 10MHz instruments with detection of nodules gt3mm
  • Can also be used to monitor nodular sizes, guide
    FNA biopsies and aspiration of cystic lesions

43
Thyroid scanning
  • Radioisotopes of iodine can be used to trace the
    fractional uptake into the gland
  • Graves disease - shows and enlarged thyroid with
    homogenous tracer uptake
  • Toxic Adenoma - shows areas of increased uptake
    with suppressed tracer uptake in remainder of
    gland
  • Toxic Multinodular goiter - Enlarged gland with
    multiple areas of increased and decreased uptake

44
Thyroid scanning
  • Subacute thyroiditis - very low uptake due to
    cell damage
  • Thyrotoxicosis factitia (self-administration of
    thyroid hormone) - low uptake
  • Cold nodules are usually benign, but have 5-10
    chance of being malignant
  • Hot nodules are almost never malignant
  • Scans are also used to follow up on thyroid
    cancer. Uptake in the thyroid bed after surgery
    may show metastatic thyroid cancer deposits.

45
Thyroid scanning
46
Fine Needle Aspiration
  • most accurate preop diagnostic modality for
    evaluation of thyroid nodules
  • Has decreased the need for thyroid surgeries by
    50 and increased yield of thyroid malignancies
    by 50
  • reports classified as benign, indeterminate or
    malignant
  • fewer than 5 false-positives on malignancies

47
Indications for Operation
Scan
Needle Bx
Cystic
Solid
Rapid recurrence
disappearance
Neg
Pos. or ?
Surgery
Surgery
growth or failure to suppress
Suppression cont.
Surgery
48
Treatment
  • Thyroidectomy
  • hemithyroidectomy - half of the thyroid is
    removed, parathyroids preserved
  • total thyroidectomy - entire thyroid is removed,
    parathyroids preserved

49
Complications of Surgery
  • complication rate is low
  • reported complications with surgery
  • transient hypocalcemia (7.1)
  • permanent hypocalcemia (0.4)
  • Vocal cord paralysis (1.2)

50
Further management
  • 131I thyroid ablation and treatment should be
    coordinated with the surgical approach
  • ablation is much more effective when there is
    less normal thyroid tissue in the thyroid bed.
  • Patient is kept on thyroid treatment for a few
    weeks post op, then withdrawn.
  • TSH rise correlates to the amount of normal
    tissue left.
  • The residual tissue is then ablated with 131I

51
Further management
  • An initial whole-body scan should be performed
    about 6 months after surgery and thyroid ablation
    for more residual tissue.
  • if positive another larger ablative dose is given
  • if negative and thyroglobulin (Tg) levels are
    low, a repeat scan should be done 1 year later
  • if negative again, then patient can be managed
    with suppressive therapy and Tg levels every 6 to
    12 months

52
Question 3
  • Which of the following malignant tumors has the
    poorest prognosis?
  • A. Anaplastic carcinoma
  • B. Follicular (well-differentiated thyroid
    carcinomas)
  • C. Papillary
  • D. Medullary thyroid carcinoma

53
Question 3
  • Which of the following malignant tumors has the
    poorest prognosis?
  • A. Anaplastic carcinoma
  • B. Follicular (well-differentiated thyroid
    carcinomas)
  • C. Papillary
  • D. Medullary thyroid carcinoma
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