Thyroid Gland Flashcards
define the artery supply to the thyroid?
superior thyroid artery
- first branch of external carotid artery
inferior thyroid artery
- branch of the thyrocervical trunk
what is the venous drainage of the thyroid?
superior thyroid vein
middle thyroid vein
inferior thyroid vein
name the thyroid lobe appendage coursing toward the hyoid bone from around the thyroid isthmus?
pyramidal lobe
name the lymph node group around the pyramidal thyroid lobe
delphian LN group
what is the thyroid isthmus?
midline tissue border between the left and right thyroid lobes
which ligament connects the thyroid to the trachea?
ligament of berry
which paired nerves must be carefully identified during a thyroidectomy?
recurrent laryngeal nerves
- found in the tracheoesophageal grooves and dive behind the cricothyroid muscle
- damage to these nerves paralyzes laryngeal abductors and causes hoarseness if unilateral and airway obstruction if bilateral
what other nerve is at risk during a thyroidectomy and what are the symptoms?
superior laryngeal nerve
- if damaged, patient will have a deeper and quieter voice
What is TRH?
thyrotropin-releasing hormone
- released from hypothalamus
- causes release of TSH
what is TSH?
thyroid-stimulating hormone
- released by anterior pituitary
- causes release of thyroid hormone from the thyroid
what are the thyroid hormones?
T3 and T4
what is the most active form of thyroid hormone?
T3
what is the negative feedback loop?
T3 and T4 feedback negatively on the anterior pituitary
- cause decreased release of TSH in response to TRH
what do parafollicular cells secrete?
calcitonin
what is the differential diagnosis of a thyroid nodule?
multi nodular goiter adenoma hyperfunctioning adenoma cyst thyroiditis carcinoma/lymphoma parathyroid carcinoma
name three types of non thyroidal neck masses
inflammatory lesions: abscess, lymphadenitis
congenital lesions: thyroglossal duct, branchial cleft cyst
malignant lesions: lymphoma, metastases, squamous cell carcinoma
what is the diagnostic test of choice for thyroid nodule?
FNA
what in a history suggests thyroid carcinoma?
neck radiation
family history
young age
male>female
what signs suggest thyroid carcinoma?
single nodule cold nodule increased calcitonin lymphadenopathy hard, immobile nodule
what symptoms suggest thyroid carcinoma?
voice change (vocal cord paralysis)
dysphagia
discomfort
rapid enlargement
what is the most common cause of thyroid enlargement?
multinodular goiter
What is Plummer’s disease?
toxic multi nodular goiter
what is the treatment of a patient with a history of radiation exposure, thyroid nodule, and negative FNA?
remove the nodule with thyroid lobectomy
name the five main types of thyroid carcinoma
- papillary carcinoma
- follicular carcinoma
- medullary carcinoma
- Hürthle cell carcinoma
- anaplastic/undifferentiated carcinoma
what are the signs/symptoms of thyroid carcinoma?
mass/nodule, lymphadenopathy
- most are euthyroid
what is a papillary carcinoma’s claim to fame?
most common thyroid cancer
what is the environmental risk of papillary adenocarcinoma?
radiation exposure
what are the associated histologic signs of papillary adenocarcinoma?
psammoma bodies
- round microscopic calcific
papillae lined by cells with clear, ‘orphan Annie eye’ nuclei and nuclear grooves
what postoperative medication should be administered for papillary adenocarcinoma?
thyroid hormone replacement, to suppress TSH
what is the most common site of metastases in papillary adenocarcinoma?
pulmonary (lungs)
describe the nodule consistent of follicular adenocarcinoma
rubbery, encapsulated
can the diagnosis of follicular adenocarcinoma be made by FNA?
no
- tissue structure is needed for a diagnosis of cancer
what histologic findings define malignancy in follicular adenocarcinoma?
capsular or blood vessel invasion