Anatomy and Embryology
From what embryologic structure does the thyroid gland originate, and if it is arrested in process of migration then it is called?
What is Endodermal diverticulum from the floor of the primitive pharynx (foramen cecum) and What is Lingual Thyroid
What protein stores thyroid hormone within follicles?
Thyroglobulin
This imaging modality is the gold standard for evaluating thyroid nodules and cervical lymph nodes.What TI-RADS level requires no follow-up or biopsy?
What is ultrasound?
If TSH is suppressed, this nuclear study helps determine if a nodule is “hot” or “cold.”
What is thyroid scintigraphy (radioiodine or technetium scan)?
What is the most common cause of hyperthyroidism and what is the most common cause of hypothyroidism in the U.S.?
Graves and Hashimoto's Disorder
Persistence of the thyroglossal duct leads to Thyroglossal Duct Cyst or Pyramidal Lobe. What is the Procedure called to fix it?
What is Sistrunk procedure
Which enzyme couples MIT and DIT residues to form T₃/T₄?
Thyroid peroxidase (TPO).
What frequency transducer is optimal for thyroid ultrasound?
High-frequency 8–12 MHz linear probe
What percent of FNAs are indeterminate (AUS/FLUS or follicular neoplasm)?
~20–25 %.
Which medication is preferred for hyperthyroidism during pregnancy?
Propylthiouracil (PTU).
What nerve runs close to the superior thyroid artery and controls voice pitch?
External branch of the superior laryngeal nerve (EBSLN).
What percent of circulating T₃ is produced by peripheral conversion of T₄?
90%
The thyroid gland volume is estimated by multiplying length × width × depth × this correction factor.
What is 0.5?
List the six Bethesda cytology categories.
I Nondiagnostic, II Benign, III AUS, IV Follicular neoplasm, V Suspicious, VI Malignant.
This iodide solution, given pre-operatively in Graves disease, acutely inhibits thyroid hormone release
What is Lugol’s solution (potassium iodide)?
What are the names of the four strap muscles in the anterior neck? Which ones are mobilized during thyroid surgery?
•Sternohyoid
•Sternothyroid
•Omohyoid
•Thyrohyoid
Mobilized ones are Sternohyoid and Sternothyroid
Name two organs where peripheral T₄→T₃ conversion occurs.
Liver and kidney (also brain, skeletal muscle, adipose).
Name three features of suspicious lymph nodes on US.
Round shape, loss of fatty hilum, peripheral vascularity/microcalcifications
What is the typical follow-up for a stable benign nodule?
Repeat US in 6–18 months; if stable → extend to 3–5 years.
Painful thyroid enlargement following a viral illness with elevated ESR but low radioiodine uptake defines this self-limited condition.
What is subacute (de Quervain) thyroiditis?
Define the boundaries of the central neck compartment (Level VI)?
Superior – hyoid; Inferior – sternal notch; Lateral – carotid sheaths; Anterior – strap fascia; Posterior – prevertebral fascia
In critically ill patients, this syndrome features low T₃, normal or low T₄, and low or normal TSH, caused by cytokine-mediated suppression of deiodinase activity and reduced peripheral conversion of T₄ to T₃ — but does not require thyroid hormone replacement.
What is euthyroid sick syndrome (non-thyroidal illness syndrome)?
Which neck levels define the “central compartment”?
Levels VI and VII (hyoid → innominate artery)
A 1.5 cm nodule yields two nondiagnostic FNAs but causes dysphagia. The most appropriate next step is this.
What is diagnostic lobectomy?
This rare fibrosing thyroiditis produces a “woody-hard,” fixed gland that can mimic carcinoma.
What is Riedel thyroiditis?