Endocrine-Thyroid

Thyroid hormones

T3, T4, Iodine, TSH, TRH, Calcitonin

T3

-Triiodothyronin: activated by TSH
-Elevated T3 and T4 concentrations in blood plasma inhibit TSH
-4 times more potent than T4
-Acts on all major tissues (except spleen and testis)
_Iodine needed to produce

T3 uses

-Increases basal metabolic rate: increases O2 and energy consumption and cell metabolism
-Stimulates protein synthesis and degradation
-Increase glycogen breakdown and glucose synthesis
-Stimulates breakdown of cholesterol
-Increase HR, CO and SV

T4

-Thyroxine
-Iodine necessary for production
-Longer 1/2 life than T3

T4 Uses

-Increase basal metabolic rate
-Protein synthesis
-regulate long bone growth
-Neural maturation
-Increase sensitivity to catecholamines (adrenaline)
-Increase CO, HR and RR

TSH

-Thyroid-stimulating hormone:Stimulates thyroid to produces T3 and T4
-Secreted by anterior pituitary
-TRH (hypothalamus) control release of TSH

TSH dx Test

-0.4-3.0 ul/mL
-Too low: Hypothyroidism
-Too high: Hyperthyroidism

Serum Free T4

-Active form of Thyroxine
-Newer and not affected by protein levels
-More accurate reflection og thyroid function
- Usually ordered with TSH test
-High: Overactive thyroid (Hyperthyroidism)
-Low: Underactive thyroid (Hypothyroidism)

Hypothyroidism

-thyroid gland doesn't make enough thyroid hormone
-TH deficiency
-Metabolic rate reduced

Primary Hypothyroidism

-Most common forms: Hoshimoto's Thyroiditis (autoimmune)
-Not enough Thyroid hormone produced

Secondary Hypothyroidism

-Pituitary gland doesn't produce enough TSH
-Usually caused by damage to pituitary gland, tumor, radiation or surgery
-Less than 5% of hypothyroidism cases

Hypothyroidism: Causes

- Congenital (rare)
-Inflammation of pituitary (releases stores TSH, but doesn't produce more)
-Iodine Deficiency (nuclear fall out destroys cells)
-Thyroidectomy
-Automimmune
-LITHIUM-based mood stabalizers
-INTERFERON
-STRESS (chronic circulating cortis

Hypothyroidism: Signs and Symptoms

-Fatigue
-Bradycardia
-Constipation
-Mental Dullness
-COLD INTOLERANCE
-Hypoventilation
-Dry Skin and Hair
-Weight gain
-Heart failure
-Hyperlidemia
-MYXEDEMA (swollen lips and thickened nose)
-Poor muscle tone
-Muscle cramps and joint pain
-THIN, BRITTLE

Hypothyroidism: Diagnosis

-Low T3 and T4
-Primary: High TSH (Trying to encourage T3 and T4 production)
-Secondary: Low TSH (pituitary's fault)

Hypothyroidism: Interventions

-Hormone replacement: Synthroid/Levothyroxine
-Range 0.1-0.2 mg/d (monitor blood levels)
-Take daily, 30-60 min before breakfast
-Ca and coffee can diminish absorption
-Can crush

Hypothyroidism: Complications

-Cause hyperthyroidism with too much Synthroid
-Myxedema coma

Myxedema Coma: Signs and Symptoms

-hyperthermia
-Decreased VS and LOC (hallucination, disorientation, seizure)
-Respiratory Failure
-Death
-common in elderly
-Swelling all over body (swollen eyes and thickened tongue)

Myxedema Coma: Causes

-Poorly controlled hypothyroidism
-Lithium, amiodarone, narcotics, anesthesia
-Infection
-Stroke
-Trauma
-GI bleeding
-Failing to take thyroid meds or meds not being absorbed

Myxedema: Treatment

-Monitor VS
-Warming blanket
-Mechanical ventilation ( b/c increased CO2)
-IV Levothyroxine (IV bc can be given fast)
- Can cause arrythmias if given too fast

Hyperthyroidism

-Too much TSH or too much TH
-Increased Metabolic rate
-Increase Beta receptors
-Causes Grave's disease

Hyperthyroidism: Causes

-Automimmune (Grave's Disease) 50-80%
-Inflammation of thyroid gland (releases stored TH but doesn't produce more)
-INgestion of too much exogenous hormone
-Pituitary tumor (Secondary)
-Increased iodine absorption thru diet
-multinodular goiter

Hyperthyroidism: Signs and Symptoms

-hypermetabolic state
-HEAT INTOLERANCE
-increased appetite
-weight loss
frequent stools
-NERVOUSNESS
-tachycardia, palpitations
-TREMOR
-heart failure
-WARM, SMOOTH SKIN
-EXOPHTHALMOS (bugged eyes)

Hyperthyroidism: S/S in Elderly

-heart failure
-atrial fib
-fatigue
-apathy
-depression

Hyperthyroidism: Diagnosis

-Elevated T3 and T4
-Low TSH (Primary)
-HIgh TSH (Secondary)
-TRH Stimluation test

TRH Stimulation Test

-baseline TSH
-Injection of TRH given to stimulate TSH release
-Second blood sample 20-30 min later
-generally used with suspected hypothyroidism (her slide says hyperthyroidism)

Thyroid Stimulating Immunoglobulin test

-shows autoantibodies produced with hyperthyroidism
-bind to TSH receptors

Hyperthyroidism: Treatment

-Proplthyiouracil (PTU) :inhibits iodine and peroxidase from their normal production of T3 and T4---> decreases production of TH
-Tapazole (methimazole): same as PTU
-Inderal (propranolol): beta-blocker to inhibit sympathetic nervous system release of NE

Hyperthyroidism: Thyroid Storm

Thyrotoxic Crisis: rare but sever
-occurs when pt is very sick or physically stressed
-Too much TH released too quickly
-Tachycardia, HTN
-fever, dehydration
-N/V/D
-coma
-death
-requires prompt tx and hospitalization

Hyperthyroidism: Thyroid Storm TX

-decrease circulating thyroid hormone and decrease production
-PTU
-INderal
-Tapazole
-IV fluids
-Cooling blanket
-Tylenol for fever (NO ASA)
-oxygen

Radioactive Iodine Therapy Precautions:Hospital

-Limit time spent with pt
-glove and gown
-avoid if pregnant
-take precautions with urine, emesis and other body fluids
-double flush toilet
-special environmental services

Radioactive Iodine Therapy: Home

-avoid close contact for a week
-sleep alone
-wash hands carefully after urinating
-avoid oral contact
-avoid pregnancy for 1 yr (men and women)

Goiter

-enlarged thyroid gland
-elevated TSH
-hyperplasia

Goiter: Causes

-Low TH
-Iodine deficiency: hyperplasia of thyroid to compensate for decreased efficacy
- can cause hypothyroidism
- 90% of goiters
-Congenital hypothyroidism
-Goitrogens: substances that suppress function of thyroid by interfering with iodine uptake (PTU

Goiter: Signs and Symptoms

-enlarged thyroid
-hypo/hyperthyroid or eurthyroid
-dysphagia (obstruction)
-difficulty breathing (airway obstruction)

Goiter: Treatment

-For too much TH: give radioactive iodine
-Thyroidectomy with obstructions
-Monitor breathing (Stridor)
-Monitor swallowing
-Dietary consult
-Have trach kit at bedside

Thyroid Cancer

-usually benign
-more common in women

Thyroid Cancer: Causes

-radiation exposure
-hyperplasia
-iodine deficiency
-goitrogens
-usually found with normal thyroid function

Thyroid Cancer: Signs and Symptoms

-hard painless nodule
-enlarged lymph node
-dysphagia
-dyspnea with obstruction

Thyroid Cancer: Diagnosis

-physical exam of enlarged nodes
-biopsy (only way to confirm)
-thyroid scan (shows cold spot with decreased activity)
-TSH and TSI

Thyroid Cancer: Treatment

-Radioactive Iodine
-chemotherapy
-thyroidectomy (partial or total)
-excellent prognosis
-most don't need tx

Thyroidectomy:Post-op Care

-monitor breathing
-don't put strain on the incision
-assess nutrition status
-monitor VS
-Thyroid hormone given to achieve normal TH
-monitor for tetany
monitor for Thyroid Crisis

Thyroidectomy: Pre-op Teaching

-Gentle ROM
-Support neck with position change
-Use incentive spirometer
-potential change of voice
-permanently low Ca (risk for tetany)
-life long hormones needed

Hypoparathyroidism

-decreased function of parathyroid
-decreased PTH
-Ca stays in bone
-hypocalcemia (locked up in bones)
-paresthesia (tingling around mouth, hands and feet)
-muscle cramps and sever spasms (tetany)
-hyperphosphatemia (not enough Vit D to reabsorb Ph, so st

Parathyroid

-4 glands at rear surface of thyroid gland
-size of a grain of rice
-produces Parathyroid hormone (PTH)

Parathyroid: Calcium

-controls amount of Ca in blood and in bones
-PTH increases blood Ca by stimulating osteoclats to break down done and release calcium
-increases GI Ca absorption
-promotes Ca conservation by kidney

Parathyroid: Phosphate

-major regulator of serum phosphate concentrations by kidneys
-inhibits proximal and distal reabsorption
-through activation of Vit D-Phosphate absorption is increased

Hypoparathyroidism: Physical Exam

-Low PTH
-Low blood Ca
-High blood Ph
-Tetany
-neuromuscular irritability
-paresthesia (numbness/tingling in mouth, hands and feet)
-muscle spasms
-cardiac dysrrhythmias
-POSITIVE CHVODTEK'S SIGN (facial spasms with tapping face)
-POSITIVE TROUSSEAU'S SIG

Hypoparathyroidism: Treatment

-IV Ca gluconate to tx severe low Ca
-Rebreathe in paper bag
-Long term Ca with Vit D
-thiazide diuretics
-no hormone replacements available

Hyperparathyroid

-overactivity of parathyroid
-increased production of PTH (harmful to bone bc constantly breaks down)
-hyper Ca
-hypo Ph

Hyperparathyroid: Signs and Symptoms

-fatigue
-depression
-confusion
-N/V
-kidney stones
-joint pain
-FRACTURES
-dysrrhythmia
-coma
-cardiac arrest
-DX with bone density test (decreased)

Hyperparathyroidism: Cause

-long term LITHIUM
-VITAMIN D deficiency (lack of sun, diet or malabsorption)
-chronic renal failure

Hyperparathyroidism: Treatment

-IV NS to dilute Ca (secondary: response to low Ca levels)
-Lasix
-Calcitonin
-Estrogen therapy
-Parathyroidectomy

Parathyroid Hormone

-acts to increase concentration of Ca in blood
--enhances release of Ca from bone
-stimulates osetoclats to reabsorbs bone through normal bone destruction
-enhances reabsorption of Ca and Mg in kidneys
-decreases reabsorption of Ph (decrease blood Ph bc e