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Hormones
- secreted cyclically
- minute amounts
- deactivated by the liver/excreted by the kidney
- - so if these don't work we have a problem
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Hypothalamus
- top of the chain
- link between the CNS and endocrine
- releasing and inhibiting hormones
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Pituitary Gland
- middle management
- anterior pituary
- produces and secretes hormones to target glands
- located at the base of the brain and connected to the hypothalmus
- Target tissues
- - thyroid
- - parathyroid
- - adrenal
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Thyroid Gland
METABOLISM
- in neck just below the cricoid cartilage
- H butterfly shape
- largest endocrine gland
- highly vascular
-
Thyroid hormones
- Metabolism:
- - Thyroxine - T4
- - triiodothyroxine- T3
- Ca levels
- - thyrocalcitonin (TCT)
- works on negative feedback
-
Thyroid hormones
- Thyroxine (T4) and Triiodothyroxine (T3)
- - metabolism
- - CHO, protein, Fat metabolism
- - cell replication, tissue growth
- - brain development- (protein synth)
- - thermogenesis
- - resistance to infection
- - serum cholesterol level
-
Thyroid hormones
TCT
- Thycalcitonin
- - lowers plasma Ca and elevates phosphate
- - when the body has too much Ca this hormone is released.
-
Thyroid disorders
- Hypothyroid
- hyperthyroid
- Goiter- enlarged thyroid- can be caused by both
-
hypothyroidism
- can effect all body systems
- risk:
- more common in women than men
- genetic disposition- ?
- inc incidence between- 40-70 yo
-
Hypothyroidism
Primary 95%
- in the gland itself- problem with gland
- atrophy** - due to aging (primary cause)
- autoimmune (Hashimoto's)- attacks thyroid itself causing < T3, T4
- congential
- iodine insufficiency- not usually in the US
- antithyroid drugs (lithium)- for bipolar
- surgery/radiation for hyperthyroidism (in neck)
-
Hypothyroidism
secondary
tertiary
- secondary- pitutary malfunction TSH
- tertiary (central)- hypothalamus malfunction (TRH)- top of the chain
-
Hypothyroidism
Patho
- iodine necessary for thyroid gland to synthesize and secrete its hormes T3 and T4
- with insufficient iodine, error in feedback mechanism and/or suppressed TH
- gland can hypertrophy in compensation (goiter)
- need iodine to produce T3 or T4
-
Goiter
worry about airway
-
Hypothyroidism 2
- decrease in TH leads to slowed metabolism
- - dec HCl in stomach
- - dec GI motility
- - bradycardia, dec cardiac contractility, increa trig/chol- atheroscerosis- incr risk for HTN
- - slow neuro function?
- decr heat production- cold intolerance
- anemia- dec in erythopoten- RBC
-
Hypothyroidism
manifestation
- mild, asymptomatic or vague- very individual
- fatigue, lethargy
- dry skin, brittle nails, hair loss
- symptoms of dec metabolism
- - weight gain
- - muscle weakness
- -- d/t altered protein metabolism
- chx in memory, speech, flat affect
- sensitive to opioids
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Myxedema
- missing thyroid hormone- undx
- seen in times of stress
- complication of hypothyroidism
- - significant lack of TH
- s/s dry, waxy type of swelling with abnormal mucopolysaccharide deposits in skin and other tissues
- - nonpitting edema - pretibial, facial
- early prevention and tx
- untx associated with atherosclerosis- greater risk for HTN
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diagnostic testing
- **most sensitive test- TSH- incre (body making too much)
- - decre T3, T4
- - decre T3U- has much hormones is bound to protein
- - decr RAIU (I 131)- Inc TH- dec bind empty (not enough to bind too)- scanning radioisotype iodine?
- - incr chol- hyperlipidemia
- - dec HCT- anemia
- - inc TRH
-
dx test cont
- Thyroid scan- size
- US
- CT, MRI
- biopsy- malignancy
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Goals and management
- correct TH deficiency
- reverse manifestations
- prevent further damage
- correct underlying cause- improve iodine intake(if r/t iodine)
- thyroid hormone replacement
- - synthroid (levothyroxine)- most pt on this is r/t aging
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Levothyroxine
- T4 converts to t3
- dosage is based on TSH
- s/e incr metabolism
- NI- slow onset, peak in 1-3 weeks
- - assess HR, incr cardiac demand (tachy, chest pain discomfort)
- - best on empty stomach
- - multiple drug interaction ie warafin
- - life long
- titrate up slowly watch the heart rate
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nursing interventions
hypothyroidism
- low cal diet w/incre fiber and H20
- temperature regulation-
- adjust insulin (thyroid may inc BS), careful use of sedatives/narcotics
- skin care/risk of infection
- constipation
- cardiac assessment (esp when u start synthroid), activity intolerance
- - assess hr, palpitations, edema
- teaching with these pt- simple instructions, teach back, handouts d/t their memory problem ans issue was concentrating
- memory, depression, concentration
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Simple goiter
- thyroid enlargement
- cause: excess TSH, inadequate iodine, 'goitrogens". immunoglobulins
- - goitrogens- cabbage, peanuts, peaches, strawberries, thyroid inhibitors like lithium- drugs and food that block thyroid
- manifestations- hoarness, dysphagia, and enlarged thyroid
- AIRWAY
-
-
TSH
- T4 t3
- thyroid antibodies0 immunoglubins attack thyroid gland
- US
-
simple goiter
management
- goal: stop enlargement, encourage regression
- thryoid hormone- synthroid
- incr iodine intake dec goitrogens intake
- subtotal thyroidectomy
- never palpate an enlarged thyroid- remember it is vascular can cause a rapid release of TH into the blood stream
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