• Laboratory Evaluation:
    • Diagnosis is always established by the measurement of:
      • Sensitive TSH and thyroid hormone levels (free T3 and free T4)
    • Thyrotoxicosis caused by TNG or Graves’ disease is usually characterized by:
      • suppressed TSH level with either:
        • Normal (subclinical) or elevated (overt) free thyroid hormone levels
      • It is insufficient to rely on the measurement of TSH or free thyroid hormones:
        • Alone to diagnose TNG or Graves’ disease:
          • Because suppression of TSH or elevation of thyroid hormones can be associated with clinical conditions other than TNG and Graves’ disease
Low TSHHigh TSH
Secondary hypothyroidismTSH-secreting pituitary tumor
Non-thyroidal illnessThyroid hormone resistance
Glucocorticoid therapy
Amiodarone use
Excessive thyroid hormone therapy
  • Other serologic findings:
    • Such as antithyroid antibodiesantithyroid peroxidase and antithyroglobulin:
      • That support the diagnosis of autoimmune thyroid disease:
        • May be detected in patients with Graves’ disease:
          • However, serum TSHR-Ab:
            • Is occasionally helpful in the diagnosis of Graves’ disease:
              • Though there is no consensus regarding its routine measurement in Graves’ disease
  • Imaging:
    • Radionuclide Imaging:
      • Radionuclide scanning and radioactive iodine uptake (RAIU):
        • Are useful tests to elucidate the cause of hyperthyroidism
      • In toxic nodular goiter (TNG):
        • The radioactive iodine (RAIconcentration is in the nodule(s), and uptake is inhibited in the surrounding tissue:
          • Giving the appearance of “patchy uptake”
        • Consequently, the total RAIU may be either:
        • Slightly raised or at the upper limit of normal
      • In Graves’ disease:
        • Because of the diffuse thyroid involvement:
          • The RAIU is always intense and increased
      • Thyroid radionuclide imaging may not be necessary in every case:
        • When the diagnosis is obvious:
          • But it is helpful in the differentiation of other clinical conditions associated with hyperthyroidism but with low RAIU
Radionuclide scan of toxic nodular goiter demonstrating intense focal uptake of several hot nodules with different degrees of suppression of adjacent thyroid tissue (A) compared with the scan from a patient with non-toxic multi-nodular goiter, showing less intense patchy radioactive iodine uptake (B).
Radionuclide scan in Graves’ hyperthyroidism demonstrating the diffuse and homogeneous nature of increased uptake in both lobes of the thyroid.

Clinical Conditions Associated with Low Radioactive Iodine Uptake and Hyperthyroidism

Thyroiditis
Iodine-induced thyrotoxicosis
Exogenous thyrotoxicosis (factitia)
Ectopic functional thyroid tissue
  • Computed tomography scan:
    • In any patient with compressive or obstructive symptoms and an MNG:
      • Chest radiography and chest computed tomography (CT) are often informative
    • Chest CT is particularly valuable to define the size and extent of the goiter:
      • Especially into the mediastinum
    • Care to avoid iodinated contrast:
      • Until the patient’s thyroid functional status must be taken into account or the significant iodine load CT contrast agent may acutely induce or worsen hyperthyroidism
A, Chest radiography showing a huge solid goiter (horizontal arrow) displacing the trachea without compression (vertical arrow). B, Neck computed tomography of the same goiter (arrows). Thyroidectomy revealed a 290-g benign thyroid gland.
  • Associated metabolic abnormalities:
    • Altered glucose metabolism:
      • Reversible hyperglycemia
      • Elevated C-peptide
      • Elevated intact proinsulin
      • Insulin resistance
    • Increased bone turnover:
      • Elevated markers of bone formation and resorption
        • Are hallmarks of untreated hyperthyroidism
    • Untreated hyperthyroidism is associated with an elevated chromogranin A level:
      • That changes in parallel with thyroid status

Metabolic Abnormalities Associated with Hyperthyroidism

Mild hypercalcemia
Myopathy
Hypokalemic periodic paralysis
Pulmonary hypertension
Cholestatic jaundice

#Arrangoiz #CancerSurgeon #ThyroidSurgeon #ParathyroidSurgeon #HeadandNeckSurgeon #ThyroidExpert #SurgicalOncologist #EndocrineSurgery #CASO #Miami #ThyroidNodule #ToxicNodularGoiter #TNG #MultinodularGoiter #GravesDisease #Hyperthyroidism #Goiter #CenterforAdvancedSurgicalOncology

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