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Hagen chapter 22 Thyroid/parathyroid

Terms in this set (70)

Thyroid function:
Regulates cell metabolism, modulates O2 consumption, resp 4 basal metabolic raye(BMR), synthesizes, stores, secretes hormones thru iodine metabolism
Thyroid gland
Produces hormones T3 & T4
Thyroid gland traps ____ from blood thru series of chemical reactions
Iodine
Low levels of thyroid hormones trigger release of
TSH
When body needs thyroid hormone, it's released into the _____
Bloodstream
Thyroid hormone released into bloodstream by action of
TSH (thyroid-stimulating hormone) or thyrotropin
TSH or thyroid-stimulating hormone is produced by
Pituitary gland
Calcitonin
A thyroid hormone
Helps maintain homeostasis of blood calcium
Calcitonin
Decreases concentration of calcium by first acting on bone to inhibit breakdown
calcitonin
Thyroid function responsible for regulating BMR that
Controls growth/development, HRT rate, neural activity
Euthyroid
State of having a normal thyroid function
Hypothyroidism
Under secretion of thyroid hormones, may b caused by low intake of iodine
Goiter
MAY b causes by the inability of the thyroid 2 produce proper amount of thyroid hormone or problem in the pituitary gland w/ controlling thyroid production
Hyperthyroidism
Over secretion of thyroid hormones
Etiologies of hyperthyroidism
Entire gland out of control, localized neoplasm (adenoma) causes overproduction of thyr horm
Clinical symptoms of HyPOthyroidism
Infancy/childhood causes cretinism leading to stunted growth/mental retardation
Clinical symptoms of HyPOthyroidism
After puberty: ^subcu tissue around eyes, myxedema (red rash on lower legs), mod weight gain
Clinical symptoms of HyPOthyroidism
Hair loss, lethargy, intellectual/motor skills slowing, cold tolerance
Clinical symptoms of HyPOthyroidism
Constipation, deep husky voice, menstrual irregularities
Clinical symptoms of HyPERthyroidism
^ metabolic rate, weight loss, ^ appetite, ^ nervous energy, tremor
Clinical symptoms of HyPERthyroidism
Excess sweating, heat intolerance, tachycardia/palpitations, exophthalmos (protruding eyes), menstrual irreg
Lab test for thyroid measures
Levels of T3 & T4 in blood
Levels of T3 & T4 r elevated w/
Hyperthyroidism
Levels of T3 & T4 r decreased w/
Hypothyroidism
Higher lab values r typical when thyroid hormones r
Low
Lower lab values r typical when thyroid hormones r
High
Nuclear medicine related to thyroid
Nuclear scintigraphy... Iodine uptake studies
(Nuclear scintigraphy) ^uptake of radionuclide w/
Hyperthyroidism, iodine starvation, thyroiditis, lithium use, hypoalbuminemia, adenomas w/ hyperfunction (hot nodules)
(Nuclear scintigraphy) decreased uptake of radionuclide w/
Hypothyroidism, thyroid hormone therapy, thyroiditis, intake of iodine substances
Small butterfly shaped gland in lower anterior neck
Thyroid gland
Thyroid gland
Largest endocrine gland in the body
Approx upper size limits of thyroid
6cm x 2cm x 2cm each lobe
Isthmus measurements
4-6 mm AP
AP dimension of each lobe should not exceed
2cm
Newborn thyroid measurement
18-20 mm x 9-8 mm
Common method for volume calc of thyroid
Ellipsoid formula l x w x thickness x 0.52 for each lobe
Normal mean thyroid volume
18.6+/- 4.5 ml
Volume slightly larger in
Males than females
_____ may call 4 ^ intake of iodine
Pregnancy
Consists of 2 lives joined by an isthmus
Thyroid gland
Pyramidal lobe
Is a variant, 20%occur, projects superiorly, usually atrophied by adulthood
Relational anatomy
...
Muscles around the thyroid gland r
Hypoechoic
Strap muscles in relation to the thyroid gland
Sternothyroideus, sternohydoideus, omohyoideus
Sternocleidomastoid muscle
More lateral/anterior (superficial) than strap muscles
Longus colli muscles
Posterior to thyroid/adjacent to cervical spine- may stimulate mass
Esophagus
Posterior to the trachea & thyroid
Minor neurovascular bundle
Posterior
Parathyroid glands
Usually 2 pr on posterior aspect, <5mm, 1pr sup to mid, 1pr inf
Arterial: superior thyroid arteries
Branches of external carotid artery
Inferior thyroid arteries
Branches of thyrocervical branch of subclavian arteries
Arterial: thyroid : peak systolic velocities
20-40cm/sec larger arteries
Superior thyroid vein
Courses to/from the internal jugular
Middle thyroid vein
Courses to/from the internal jugular
Inferior thyroid vein
Courses to/from the in nominate (brachiocephalic)
Sono Eval thyroid or
Pt position supine w/ pillow under shoulders w/ neck extended
High frequency 7.5-15 MHz linear-array
Transducer to b used on thyroid scan (wide foot print vector may b used IF high freq)
Sono appearance (echogenicity):
Medium level echoes, ^ echogenic than adjacent muscles, homogeneous, fine, vey Ty smooth
Sono exam protocol minimum
3 lng, rt/lt; 3 trans, rt/lt; measurements 3 dimensions,
Sono exam protocol minimum
Lng/trans isthmus, AP dimension isthmus, Doppler any nodules, survey adj anatomy for enlarged lymph nodes
Other imaging
Nuclear medicine: isotope I123
Cold nodules
Lack of uptake of radiopharmaceutical
Hot nodules
Usually benign
90% of palpable nodules r
Cold
90% of cold, palpable nodules r
Benign
10% of cold, palpable nodules r
Malignant
90% of cold, palpable nodules r
Benign
10% of cold, palpable nodules r
Malignant
High frequency 7.5-15 MHz linear-array
Transducer to b used on thyroid scan
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