Thyroid Flashcards
When does the thyroid gland begin to develop during human embryo formation?
Around the 4th week of gestation.
Where does the thyroid gland initially develop?
At the floor of the primitive pharynx, just below the base of the tongue.
What is the thyroid gland’s initial form during early development?
A small endodermal diverticulum.
During which weeks of fetal development does the thyroid migrate downward?
7th to 8th week.
What is the final position of the thyroid gland after migration?
Anteriorly to the trachea.
What structure connects the two lobes of the thyroid gland?
The isthmus.
Common ectopic sites for thyroid tissue include _______.
- Lingual Thyroid
- Mediastinal Thyroid
- Prelaryngeal Thyroid
Where is the thyroid gland located in the body?
In the anteroinferior neck, just below the thyroid cartilage.
What is the characteristic shape of the thyroid gland?
Butterfly shape.
What are the dimensions of an adult thyroid lobe?
- Length: 40–60 mm
- Anteroposterior diameter: 20–30 mm
- Width: 15–20 mm
What arteries supply the thyroid gland?
- Superior thyroid arteries
- Inferior thyroid arteries
What is the primary function of the thyroid gland?
Regulating metabolism by producing T3 and T4 hormones.
What hormones are primarily produced by the thyroid gland?
- Triiodothyronine (T₃)
- Thyroxine (T₄)
- Calcitonin
What is the role of calcitonin?
Helps lower blood calcium levels.
What is hypothyroidism?
A condition where the thyroid produces insufficient amounts of thyroid hormones.
Common causes of hypothyroidism include _______.
- Hashimoto’s Thyroiditis
- Iodine deficiency
- Thyroidectomy
- Radioactive iodine treatment
Symptoms of hypothyroidism include _______.
- Weight gain
- Fatigue
- Cold intolerance
- Constipation
What is hyperthyroidism?
A condition where the thyroid gland produces excessive amounts of thyroid hormones.
Common causes of hyperthyroidism include _______.
- Graves’ Disease
- Toxic nodules
Symptoms of hyperthyroidism include _______.
- Weight loss
- Increased appetite
- Heat intolerance
- Sweating
What does a TSH test measure?
The level of TSH in the blood.
What does a high TSH level indicate?
Hypothyroidism.
What is the normal range for TSH?
0.4 - 4.0 mIU/L.
What does the free T₃ and T₄ test measure?
Levels of active thyroid hormones circulating in the blood.
What is the purpose of the thyroglobulin test?
Measures the level of thyroglobulin, a protein produced by the thyroid.
What is the purpose of the radioactive iodine uptake (RAIU) test?
Measures the amount of iodine the thyroid absorbs.
What does an increased uptake in the RAIU test indicate?
Hyperthyroidism.
What imaging technique is used to visualize the thyroid gland?
Ultrasound (Sonography).
What position should a patient be in for a thyroid ultrasound?
Supine position with a pillow under their shoulders.
What is the purpose of fine needle aspiration (FNA) biopsy?
To collect tissue from the thyroid for examination.
What defines nodular thyroid disease?
Presence of one or more abnormal lumps (nodules) in the thyroid.
What are the types of nodular thyroid disease?
- Solitary Nodules
- Multinodular Goiter (MNG)
- Colloid Nodules
What is the definition of Nodular Thyroid Disease?
Presence of one or more abnormal lumps (nodules) in the thyroid.
What are the types of Nodular Thyroid Disease?
- Solitary Nodules
- Multinodular Goiter (MNG)
- Colloid Nodules
What characterizes a benign thyroid nodule on ultrasound?
Homogeneous, well-defined, may have a hypoechoic halo.
What are the sonographic features of malignant thyroid nodules?
- Hypoechoic with irregular borders
- Microcalcifications
- Increased vascularity
What is a Benign Follicular Adenoma?
A common, non-cancerous thyroid tumor.
How does a Colloid Cyst appear on ultrasound?
Anechoic (dark), well-defined walls, distal acoustic enhancement.
What is the clinical feature of Papillary Thyroid Carcinoma?
Often presents with a hard, firm nodule, possibly with cervical lymphadenopathy.
What are the sonographic findings of Follicular Thyroid Carcinoma?
- Hypoechoic
- Irregular borders
- Increased vascularity
What is Medullary Thyroid Carcinoma associated with?
May be associated with MEN (Multiple Endocrine Neoplasia) syndrome.
What is the significance of Anaplastic Carcinoma?
Rarest and most aggressive thyroid cancer.
What are the sonographic findings of Lymphoma in the thyroid?
- Large, non-vascular, hypoechoic, lobulated mass
- Possible necrosis and surrounding lymphadenopathy
What is the origin of Thyroid metastasis?
Uncommon and can come from primary cancers like breast, kidney, and melanoma.
True or False: FNA Biopsy is the gold standard for confirming malignancy in thyroid lesions.
True
What are key sonographic signs of malignant lesions?
- Hypoechoic Mass
- Microcalcifications
- Irregular Borders
- Taller-than-Wide appearance
- Increased Vascularity
What is Aplasia in the context of congenital abnormalities of the thyroid gland?
The complete absence of the thyroid gland.
What are the clinical features of congenital hypothyroidism due to Aplasia?
- Developmental delays
- Poor feeding
- Jaundice in infants
What is Hypoplasia?
Underdevelopment of the thyroid gland, resulting in reduced thyroid function.
Where is ectopic thyroid tissue commonly located?
- Sublingual or Lingual Thyroid
- Prelaryngeal Thyroid
- Substernal Thyroid
What imaging technique is often used to locate ectopic thyroid tissue?
Scintigraphy (radioactive iodine scan).
What is a Thyroglossal Duct Cyst?
Occurs when the thyroglossal duct does not atrophy during development.
What is the typical presentation of a Thyroglossal Duct Cyst?
Painless, movable neck mass.
What are the sonographic features of a Branchial Cleft Cyst?
- Primarily cystic
- Can have complex or solid components if infected.
What is the cause of Cervical Lymphadenopathy?
Enlargement of lymph nodes due to reactive hyperplasia, neoplasms, metastasis, or inflammatory processes.
What are the sonographic features of normal lymph nodes?
- Oval-shaped
- Symmetric and homogeneous cortex
- Echogenic central hilum
What is the purpose of postthyroidectomy neck sonography?
To evaluate patients after a thyroidectomy for thyroid cancer to detect possible recurrence or metastasis.
What are the sonographic findings of primary hyperparathyroidism?
- Adenoma typically appears as hypoechoic
- Increased vascularity
- Most adenomas are located near the superior or inferior poles of the thyroid.
What characterizes Parathyroid Hyperplasia?
Enlargement of all four parathyroid glands, often linked to chronic renal failure.
What is the prevalence of Parathyroid Carcinoma?
Rare, accounting for about 1% of hyperparathyroidism cases.
What are the causes of Secondary Hyperparathyroidism?
- Chronic hypocalcemia
- Chronic kidney disease
- Vitamin D deficiency
- Malabsorption syndromes
What are the locations of ectopic parathyroid tissue?
- Mediastinum
- Retropharyngeal
- Intrathyroid
- Carotid sheath
What is the typical appearance of an Abscess on ultrasound?
- Complex cystic mass with low-level echogenicity
- Irregular walls and possible septations.
