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Subclincal Thyroid Disease and the Work-up of a Thyroid Nodule


Subclincal Thyroid Disease and the Work-up of a Thyroid Nodule Jared Bunevich MS IV LECOM – PowerPoint PPT presentation

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Title: Subclincal Thyroid Disease and the Work-up of a Thyroid Nodule

Subclincal Thyroid Disease and the Work-up of a
Thyroid Nodule
  • Jared Bunevich MS IV

  • Discuss the diagnosis and clinical presentation
    of subclincal hypothyroidism
  • Discuss the controversies surrounding treatment
    of subclincal hypothyroidism
  • Discuss the diagnosis and clinical presentation
    of subclincal hyperthyroidism
  • Discuss the controversies surrounding the
    treatment of subclincal hyperthyroidism
  • Discuss cost-effective and clinically based
    work-up of a Thyroid Nodule

Subclinical Hypothyroidism
  • Definition Increased TSH levels in the face of
    normal free thyroxin (T4)
  • Even though referred to as subclinical, patients
    still may have symptoms (fatigue, weight gain,
    muscle loss)

Subclinical Hypothyroidism
  • Diagnosis
  • Increase serum TSH and free T4 within the normal
  • Measurement of TSH is sensitive and specific,
    even though free T4 levels maybe within normal
    limits the actual levels of T4 maybe less than
    that patient previously had
  • 7 of women and 3 of men aged 60-89 were found
    to have TSH greater than 10 uU per mL without
    obvious hypothyroidism clinical findings
  • Risk Factors for Diagnosis family history of
    thyroid disease, autoimmune disease, previous
    head and neck radiation, drugs (lithium,

Subclincal Hypothyroidism
  • Guidelines
  • U.S. Preventive task force recommends routine
    universal screening NOT be carried out on
    asymptomatic patients because clinical benefit is
  • American Thyroid Association recommends screening
    in men and women every five years beginning at
    age 35

Subclincal Hypothyroidism
Subclinical Hypothyroidism
  • Course
  • TSH may return to normal after several month
    reassessment and can be attributed to
  • Lab error
  • Silent thyroiditis
  • Sub clinical hypothyroidism with detectable
    antithyroid antibodies progesses to overt
    hypothyroidism at about 5 per year, and maybe as
    high as 20 in the elderly and patients with high
    antithyroid antibodies

Subclinical Hypothyroidism
  • Symptoms
  • In studies comparing euthyroid individuals and
    subclinical hypothyroid easy fatigability, cold
    intolerance and dry skin were more common in the
    subclincal hypothyroid group
  • Arem et al and Franklin et al found a decrease in
    the LDL of patients with subclincal
    hypothyroidism when treated with synthyroid
  • Cooper et al found the PEPLVET was found to
    significantly improve in subclincal patients when
    treated with levothyyroxine

Subclincal Hypothyroidism
  • When should we treat?
  • When TSH is consistently 10 uU/mL on two or more
    occasions six months apart and the patient has
    increased antithyroid antibodies
  • Persons who have hypothyroid type complaints and
    elevated TSH should be treated (even if TSH is in
    the 5-10 uU/mL range)

Subclinical Hypothyroidism
Subclinical Hypothyroidism
  • Treatment options
  • Overt Hypothyroidism
  • Typical Patient
  • Start with Levothyroxine 25-50 ug daily and
    increased slowly by 25-50 ug to 75 or 100 ug
  • Elderly and the Patients with heart disease
  • Start a lower doses and progress at smaller
    increments to 50 or 100 ug or 1.6 ug/kg
  • Subclinical Hypothyroidism
  • Levothyroxine 25-50 ug with a repeat TSH in 6
    weeks with the goal of maintaining TSH in the
    normal range
  • Smaller overall dosages are more commonly utilized

Subclinical Hyperthyroidism
Subclinical Hyperthyroidism
  • Diagnosis
  • Definition normal serum free thyroxine and free
    triiodothyronine with a TSH suppressed below the
    normal levels
  • Physical exam will NOT yield an enlarged thyroid

Subclinical Hyperthyroidism
  • Differential Diagnosis
  • Silent thyroiditis
  • Steroid use
  • Dopamine administration
  • Pituitary dysfunction
  • Early Hashimotos or Graves disease
  • Multinodular goiter (particularly in the elderly)

Subclinical Hyperthyroidism
  • Etiology
  • Vanderpump et al found subclinical
    hyperthyroidism progresses to overt
    hyperthyroidism at 1-3 year
  • There is an increased risk of cardiac and bone
    density abnormalities

Subclinical Hyperthyroidism
  • Cardiac Abnormalities
  • A-fib risk increased 3-5 fold in persons older
    than 60 with decreased TSH values (Sawin et al)
  • A small study showed resting baseline left
    ventricular diastolic filling was impaired at
    maximal exercise
  • In addition patients increased interventicualr
    wall thickness

Subclinical Hyperthyroidism
  • Bone Density
  • Premenopausal women with subclinical
    hyperthyroidism do NOT appear to be at risk for
    increased bone loss
  • 41 studies including 1200 postmenopausal patients
    found patients with suppressed TSH values were
    associated with significant bone loss in the
    lumbar spine and femur

Subclinical Hyperthyroidism
  • Neuropsychiatic Boomer et al
  • Reduced feelings of well being
  • Inability to concentrate
  • Feelings of fear

Subclinical Hyperthyroidism
  • Diagnostic Assessment
  • TSH, T3, T4 evaluation
  • Monitor for three months if indicative of
    subclinical hyperthyroidism
  • If TSH concentration remains suppressed a RAIU is
    indicated with possible sonography
  • Also, in elderly patients consider ECG, bone
    mineral density exams

Subclinical Hyperthyroidism
  • Treatment options
  • Antithyroid medications
  • PTU 50-100 mg /day
  • Mehtimazole 5 mg /day if not pregnant
  • Initiate if RAIU is positive or if patient is
    symptomatic for 6-12 months
  • Surgery
  • Non-complaint or patients who develop Garves,
  • Radioactive iodine
  • Only cost-effective if medical therapy fails x2

Thyroid Nodule Work-up
  • Clinical Hx
  • Consider
  • Age
  • Malignancy is higher in youth with nodules
  • Sex
  • Less common in men but more likely to be
  • Family history
  • History of neck radiation
  • 0.5 Gy increases risk of thyroid cancer 1-7 up
    to 30 years later

Thyroid Nodule
  • Tests
  • Calcitonin Small reports suggest meduallry CA
    mets can be prevented
  • Cost effectiveness unclear
  • FNA Gold standard to evaluate thyroid nodule
  • Adequate specimen can be obtained in 90 of
  • False negative and false positive are reported to
    be as low as 5

Thyroid Nodule
  • FNA
  • 5-8 of aspirates are diagnostic of malignancy
  • 10-20 considered suspicious for malignancy
  • 2-5 fail to provide adequate samples
  • With suspicious findings 25 of patients are
    found to have malignancy
  • If patients chooses, questionable biopsy can be
    followed with sonography every 6 months

Thyroid Nodule
  • Thyroid Sonography
  • Sensitive to 3 mm nodules
  • 3-20 of nodules are found to be cystic
  • Cystic lesions have lower incidence of malignancy
    than solid masses (3 vs. 10)

Thyroid Nodule
Thank you
  • Questions?
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