thyroid disorders in everyday care chris vreeland, rn, msn, np-c georgia mountain endocrinology, pc
TRANSCRIPT
Thyroid disorders in everyday care
Chris Vreeland, RN, MSN, NP-c
Georgia Mountain Endocrinology, PC
Introduction• One in ten Americans have a thyroid
disorder• Body’s response to thyroid disorders is
fatigue - most common reason to seek healthcare.
• Women particularly affected by thyroid imbalanceWeightFertilityPregnancyMenopauseOsteoporosis
Thyroid Hormone Action
• Activates nuclear receptors which regulate expression of thyroid hormone-responsive genes:Fetus & neonate: differentiation
of target tissuesChildhood:
differentiation/proliferationAdolescent: role in action of sex
steroids
Thyroid Hormone Action
• Gene expression (continued)
All ages: • Regulates energy production
• Regulates functional /structural proteins
• Regulates action of other hormones - glucocorticoids, mineralocorticoids, growth factors, biologic amines (catecholamines)
Negative Feedback Loop
• Thyroid hormone inhibits pituitary secretion of TSH
• Hypothalamus plays crucial role• TSH very sensitive indication index
of action• TSH & thyroid hormones maintained
in a certain relationship• Modified by TBG (thyroxine-binding
globulin)
Negative Feedback Loop
Hyperthyroidism • Elevated serum thyroid level• Decreased TSH
Hypothyroidism • Decreased serum thyroid levels• Increased TSH
Serum Levels of Thyroid Hormones
• T3 regulates peripheral action of hormone
• T3 & T4 both released from gland
• Peripheral conversion of T4 to T3 occurs in liver and target tissues
• In presence of liver damage, T3 conversion may be low despite good levels of T4
TBG Metabolism
• T4 transported to tissue by TBG• High serum TBG (liver damage,
pregnancy, OCP’s, HRT) lowers serum concentrations of free T4 which decreases amount of substrate (T4) that can be converted to T3
• Indirect measure of TBG abnormality is T3 uptake
Causes of Thyroid Disorders
Hyperthyroidism• Graves’ disease:
• Autoimmune • TSH receptor antibodies
• Thyroiditis: • Sub-acute• Post-partum
• Pituitary tumor - TSH producing
Causes of Thyroid Disorders
Hypothyroidism (High TSH, low T3, T4)
• Hashimoto thyroiditis: • Autoimmune
TPO and thyroglobulin antibodies• RAI: radioactive iodine ablation• Surgery• Antithyroid drugs• Goitrogens: lithium, amiodarone
Normal Hormone Levels
• TSH: 0.4-5.5 MIU/L
• Total T3: 60-181 NG/DL
• Total T4: 4.5-12.5 MCG/DL
• T3 Uptake: 22-35%
Hypothyroidism
SymptomsFatigueWeight gainCold feelingDry hair, nails,
skinHair lossHeavier or
longer menses
ConstipationPeripheral
edemaPeriorbital
edemaBradycardiaHypotension Infertility
Hypothyroidism
• Treatment:
• Hormone replacement (L-T4)
Absorbed from small intestine6-day half-life
• Daily dosing: 0.025-.300 mgs• Branded preparations preferred to
genericSynthroid Levoxyl Tirosint
Hypothyroidism• Treatment
Initial dose:1.7 mcg per kg
Pregnant: may need 1.8 mcg per kgElderly: usually start at lower doses,
esp. with angina or CAD• Monitoring
6-8 weeks after any dose changeAnnually once stableEach trimester in pregnancy
Hypothyroidism• Myxedema Coma
End stage of uncompensated hypothyroidism
Presents most often in elderly and women in winter months
Present in respiratory failure, hypotension, bradyarrythmia, along with serious precipitating illness
Treatment is T4 IV @ 1/10th dose of oral
ICU admit for multi-system failure
HypothyroidismPearls
Most patients reports feeling best with TSH between 1-2
If TSH normal, but patient still not feeling good, think low T3; may need Cytomel (oral T3)
Depression very commonInadequate treatment can contribute to
infertilityLook for recent onset of symptom with
family history of thyroid disease
Hyperthyroidism
SymptomsAnxietyPalpitationsUnintended weight lossDecreased or absent mensesOily skinFine, silky, oily-appearing hairHeat intoleranceExopthalmos (not all cases)Tachycardia
Hyperthyroidism
Treatment• Anti-thyroid drugsMethimazole
Inhibits thyroid hormone synthesis in the thyroid gland
PTU
Inhibits thyroid hormone synthesis in the thyroid gland & inhibits peripheral conversion of T4 to T3
HyperthyroidismDosing:
• Tapazole: 10 mg BID or TID• PTU: only 50 mg tablets available
Usual starting dose: 2 tabs TID; may double dose if necessary
• Both very effective at lowering thyroid hormone levels
• TSH will stay suppressed several month
HyperthyroidismDosing:
Monitor every 4-6 weeksWhen TSH rises, may need to add
T4 (thyroid hormone)Want to leave on ATD’s long
enough to allow TSH receptor antibodies to decrease & induce remission; usually 12-18 months
Plan to withdraw med at 12-18 months to evaluate remission status
Hyperthyroidism
Side effects of anti-thyroid drugs:• Leucocytopenia• Agranulocytosis-most serious• Pernicious anemia• Thrombocytopenia• Hepatic dysfunction• Allergy (discoid rashes)
Evaluate with CMP, CBC, & thyroid hormone levels every 4-6 months
Hyperthyroidism
Radioactive Iodine Ablation
• Administration of I131 iodine by mouth
• Used after TFT’s normal or if unable to control hyperthyroidism with drugs
• Usually destroys gland over 3-6 months
Hyperthyroidism
Radioactive Iodine Ablation• Induces permanent hypothyroidism• May cause post-treatment thyroid
storm (rare)• May cause aggravation of Graves’
eye disease• Pregnancy should be prevented
within 6 months after treatment
Hyperthyroidism
Surgery• When disease state or gland size
can’t be controlled with drugs• When gland causing obstructive signs
Difficulty breathing either supine or upright
-Evaluated by PA & LAT CXRDifficulty swallowing food
-Evaluated by barium swallow
Hyperthyroidism• Thyroid Storm
• Most often with Graves’ disease• Levels same as with Graves’• Cardinal signs:
Temperature 102 to 1050
Profuse sweating
Marked tachycardia (120-140 pulse rate or higher)
Atrial fibrillation• Usually induced by concurrent infection
or surgery on hyperactive gland
HyperthyroidismThyroid storm
• TreatmentPTU orally or by NG tubeTapazole not favored because it does
not inhibit peripheral conversion of T4 to T3
Beta blockade, PO or IVSupportive therapy for fever,
dehydrationPerhaps iodine solution or
corticosteroids
HyperthyroidismGraves’ Eye Disease:• Caused by antibody effect on orbital
tissue• Symptoms include:
EdemaInflammationHypertrophy of extra ocular muscles &
orbital fat• Exopthalmos upper & lower lid retraction,
strabismus, herniated orbital fat
Hyperthyroidism
Graves’ Eye Disease:• Should be stabilized for 6 months
prior to any other treatment modality• Exception is optic neuropathy
caused by strangulation of optic nerve
• Extent of protrusion measured by increase in distance between lateral orbital rim and anterior aspect of eye
Thyroid Nodules
• May be a single nodule or larger of multiple nodules
• 95% benign• More common in women• More likely malignant in men• Increase in size while on T4 therapy
worrisome for malignancy
Thyroid Nodules• Note size, consistency and mobility
on physical exam• Evaluate for tracheal deviation or
esophageal obstruction• Usually TSH suppressed, T3 and T4
levels normal• Antibodies may be present, but
more likely they are not not• Ultrasound best way to diagnose
Thyroid NodulesTreatment• Multinodular gland without dominant
nodule: T4 to shrink if TSH not suppressed
• Single nodule 1 cm or greater: fine needle aspiration biopsy
• Enlarging nodule despite “good” dose of T4 or indeterminate or malignant result from FNA indicates need for surgery
Thyroiditis
• Most common cause: chronic autoimmune thyroiditis or post-partum thyroiditis
• Next is sub acute thyroiditis
• More rare: acute suppurative thyroiditis
Thyroiditis
Post-partum thyroiditis• May occur anytime in the first year,
but most common in first 3 months• Usually have hyperthyroid
symptoms first, followed by hypothyroid findings
• Gland usually enlarged• Will not have other markers for
inflammation: fever, tenderness, high sed rate
Thyroiditis
Post-partum thyroiditis• Usually spontaneously resolve• May need temporary medication
support for symptomsBeta blockers for tachycardiaTranquilizers for anxietyT4 for hypothyroidism
• Can progress to permanent hypothyroidism
Thyroiditis
Sub acute• Usually follows viral illness• Gland is swollen, tender• Sed rate elevated >50mm/hour• May have fever, even fairly mild• Leucocytosis• Follows usual pattern of transient
hyperthyroidism, then hypothyroidism, then euthyroid
Thyroiditis
Sub acute• Treatment:
SymptomaticNSAIDS for pain, feverPrednisone for severe pain
unrelieved by aboveBeta blockers for hyper phaseThyroid replacement for hypo phaseResolve spontaneously
Questions?
Thank you!