Thyroid disorders in everyday care

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Thyroid disorders in everyday care

• Chris Vreeland, RN, MSN, NP-c
• Georgia Mountain Endocrinology, PC

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Introduction

• One in ten Americans have a thyroid disorder
• Bodys response to thyroid disorders is fatigue -
  most common reason to seek healthcare.
• Women particularly affected by thyroid imbalance
• Weight
• Fertility
• Pregnancy
• Menopause
• Osteoporosis

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Thyroid Hormone Action

• Activates nuclear receptors which regulate
  expression of thyroid hormone-responsive genes
• Fetus neonate differentiation of target
  tissues
• Childhood differentiation/proliferation
• Adolescent role in action of sex steroids

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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)

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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)

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Negative Feedback Loop

• Hyperthyroidism
• Elevated serum thyroid level
• Decreased TSH
• Hypothyroidism
• Decreased serum thyroid levels
• Increased TSH

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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

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TBG Metabolism

• T4 transported to tissue by TBG
• High serum TBG (liver damage, pregnancy, OCPs,
  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

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Causes of Thyroid Disorders

• Hyperthyroidism
• Graves disease
• Autoimmune
• TSH receptor antibodies
• Thyroiditis
• Sub-acute
• Post-partum
• Pituitary tumor - TSH producing

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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

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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

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Hypothyroidism

• Symptoms
• Fatigue
• Weight gain
• Cold feeling
• Dry hair, nails, skin
• Hair loss
• Heavier or longer menses

• Constipation
• Peripheral edema
• Periorbital edema
• Bradycardia
• Hypotension
• Infertility

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Hypothyroidism

• Treatment
• Hormone replacement (L-T4)
• Absorbed from small intestine
• 6-day half-life
• Daily dosing 0.025-.300 mgs
• Branded preparations preferred to generic
• Synthroid
• Levoxyl
• Tirosint

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Hypothyroidism

• Treatment
• Initial dose
• 1.7 mcg per kg
• Pregnant may need 1.8 mcg per kg
• Elderly usually start at lower doses, esp.
  with angina or CAD
• Monitoring
• 6-8 weeks after any dose change
• Annually once stable
• Each trimester in pregnancy

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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 _at_ 1/10th dose of oral
• ICU admit for multi-system failure

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Hypothyroidism

• Pearls
• 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 common
• Inadequate treatment can contribute to
  infertility
• Look for recent onset of symptom with family
  history of thyroid disease

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Hyperthyroidism

• Symptoms
• Anxiety
• Palpitations
• Unintended weight loss
• Decreased or absent menses
• Oily skin
• Fine, silky, oily-appearing hair
• Heat intolerance
• Exopthalmos (not all cases)
• Tachycardia

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Hyperthyroidism

• Treatment
• Anti-thyroid drugs
• Methimazole
• Inhibits thyroid hormone synthesis in the thyroid
  gland
• PTU
• Inhibits thyroid hormone synthesis in the thyroid
  gland inhibits peripheral conversion of T4 to
  T3

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Hyperthyroidism

• Dosing
• 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

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Hyperthyroidism

• Dosing
• Monitor every 4-6 weeks
• When TSH rises, may need to add T4 (thyroid
  hormone)
• Want to leave on ATDs 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

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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

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Hyperthyroidism

• Radioactive Iodine Ablation
• Administration of I131 iodine by mouth
• Used after TFTs normal or if unable to control
  hyperthyroidism with drugs
• Usually destroys gland over 3-6 months

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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

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Hyperthyroidism

• Surgery
• When disease state or gland size cant be
  controlled with drugs
• When gland causing obstructive signs
• Difficulty breathing either supine or upright
• -Evaluated by PA LAT CXR
• Difficulty swallowing food
• -Evaluated by barium swallow

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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

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Hyperthyroidism

• Thyroid storm
• Treatment
• PTU orally or by NG tube
• Tapazole not favored because it does not inhibit
  peripheral conversion of T4 to T3
• Beta blockade, PO or IV
• Supportive therapy for fever, dehydration
• Perhaps iodine solution or corticosteroids

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Hyperthyroidism

• Graves Eye Disease
• Caused by antibody effect on orbital tissue
• Symptoms include
• Edema
• Inflammation
• Hypertrophy of extra ocular muscles orbital fat
• Exopthalmos upper lower lid retraction,
  strabismus, herniated orbital fat

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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

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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

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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

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Thyroid Nodules

• Treatment
• 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

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Thyroiditis

• Most common cause chronic autoimmune
  thyroiditis or post-partum thyroiditis
• Next is sub acute thyroiditis
• More rare acute suppurative thyroiditis

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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

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Thyroiditis

• Post-partum thyroiditis
• Usually spontaneously resolve
• May need temporary medication support for
  symptoms
• Beta blockers for tachycardia
• Tranquilizers for anxiety
• T4 for hypothyroidism
• Can progress to permanent hypothyroidism

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Thyroiditis

• Sub acute
• Usually follows viral illness
• Gland is swollen, tender
• Sed rate elevated gt50mm/hour
• May have fever, even fairly mild
• Leucocytosis
• Follows usual pattern of transient
  hyperthyroidism, then hypothyroidism, then
  euthyroid

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Thyroiditis

• Sub acute
• Treatment
• Symptomatic
• NSAIDS for pain, fever
• Prednisone for severe pain unrelieved by above
• Beta blockers for hyper phase
• Thyroid replacement for hypo phase
• Resolve spontaneously

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• Questions?

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• Thank you!