Thyroid Disorders Lecture Powerpoint Flashcards
Thyroid disease epidemiology
- Most autoimmune
- Women>men
- Familial predisposition
- Radiation exposure risk
Drug effects on the thyroid
- Estrogen therapy increases thyroid binding and thus may require increased dosing of thyroid hormone to maintain free hormone levels
- Biotin in popular supplements can interfere with lab testing (hold 48 hrs before testing)
- supplements such as antacids can prevent absorption of thyroid hormone
Differential for hyperthyroidism causes (5)
- Graves disease
- Toxic multinodular goiter
- Toxic adenoma
- Subacute thyroiditis
- Iatrogenic origin
Common presentation of hyperthyroidism (4)
- Sweating, tremor, palpitations
- widened pulse pressure and tachycardia
- proximal muscle weakness
- lid lag
Graves disease
Most common hyperthyroid disease onset of 20-50 years of age where an individual has developed autoantibodies for the TSH receptor at the thyroid causing excessive thyroid activity
Graves opthalmopathy
Immunologic mediated accumulation of extracellular water and ground substance that only occurs in about 20% of patients with graves disease unless they smoke which greatly increases risk, can result in diplopia or vision loss (optic nerve can stretch out causing everything to get green hue)
Lab results (TSH, free T3/4, thyrotropin receptor antibody test) in Graves disease
- TSH low
- T3/4 elevated
- Positive thyrotropin receptor antibody test
Hyperthyroidism from Graves disease treatment options (5) and ADR (1)
- Antithyroid drugs tapazole and PTU (block production of thyroid hormone), B blockers to control side effects, irradiation therapy, surgery
- Agranulocytosis (leukopenia)
Why is tapazole preferred to PTU for treatment of hyperthyroidism?
-It is not as hepatotoxic, but preference is reversed in pregnancy
Hyperthyroidism from Graves disease opthalmoapthy best and worst treatment options
- Antithyroid drugs tapazole and PTU are best
- Irradiation therapy is the worst
Subacute thyroiditis presentation (4)
- One week onset palpitations, tremor, sweating
- post URI onset
- Widened pulse pressure
- Can have tender thyroid
Subacute thyroiditis progression
- Initial phase of hyperthyroidism from healthy stores of thyroid hormone being released due to viral mediation
- Later transient phase of hypothyroidism
- Total resolution by 2-3 months
Subacute thyroiditis lab evaluation
Varies by phase
Subacute thyroiditis treatment options (4)
- Analgesics/NSAIDs
- B blocker in hyperthyroid phase
- thyroid hormone if hypothyroid phase
- Self limiting and does not return
Presentation of new onset of afib in elderly indicates need for…
….thyroid studies
Subclinical hyperthyroidism
A low serum TSH with normal free T4 and T3 with usually few or no symptoms of hyperthyroidism often with variable natural history and reversion to normal TSH within a year
Findings in subclinical hyperthyroidism that warrant further management (3)
- Change in bone mineral density
- Increased frequency of afib
- Reduced exercise tolerance
Subclinical hyperthyroidism management
Varies depending on patient
Hypothyroidism presenting symptoms (6)
- Fatigue
- Weight gain
- Cold intolerance
- Hypertension
- Edema
- delay in DTR
Peroxidase antibody
Test for hypothyroidism, if positive usually indicates hashimoto’s hypothyroidism
Hypothyroidism can be brought on by ___ or ___ iodine
excess, shortage
Hypothyroidism lab evaluation
- Elevated TSH
- Free T4/3 is low
Hypothyroidism treatment options (1)
-Synthroid (L thyroxine)
Subclinical hypothyroidism
Normal free T4 and 3 with slightly elevated TSH, diagnosis based on test results as clinical symptoms and signs are nonspecific, usually etiology is from hashimoto’s or prior ablative therapy, can become overt if not treated when TSH >10mU/L or other condition present, otherwise monitored
Amiodarone and thyroid function
Can cause toxic effect on thyroid cell due to high iodine content, usually in a patient with underling hashimoto’s hypothyroidism and thus has the same signs and symptoms of hypothyroidism either type I (excess iodine) or type II (destructive thyroiditis)
Lithium and thyroid function and treatment (1)
Taken up by thyroid cells but cannot be utilized and thus inhibits formation and secretion of T3/4, changes in patients with underlying hashimoto’s hypothyroidism (goiter, fatigue), treated with supplemental synthroid
Postpartum thyroiditis
Presents like hyperthyroidism in the setting of postpartum approx 4-7% of population due to inflammation causing same course as subacute thyroiditis (hyperthyroid phase that is severe and looks like graves but lacks thyroid stimulating immunoglobin levels and gets better with time followed by hypothyroid phase)
Postpartum thyroiditis treatment options (3)
- Self limiting and recurs with future pregnancy***
- B blockers for hyperthyroid phase
- Thyroid replacement for hypothyroid phase
Pregnancy and thyroid function
-hCG has weak stimulating effect on thyroid causing hCG mediated hyperthyroidism which is transient and subclinical that is self limiting but may cause hyperemesis gravidarum (lots of N/V)
Hyperthyroidism treatment of choice in pregnant woman with graves disease
-PTU (does cross placenta, need to give lowest amount to keep mother’s levels normal)
Hypothyroidism during pregnancy left untreated is associated with these 3 things, what is it treated with?
- preeclampsia
- preterm labor
- newborn neuropsycho impairment
-T4 therapy at a higher dose (mother and infant)
Thyroid cancer frequency, diagnostic tests (2)
-only 5% of nodules are cancer (relatively rare), ultrasound determine solid vs cyst and size (<1cm no clinical significance) and regular border no concern or fine needle aspiration
Hot vs cold nodules
Hot have high radiologic activity and cold do not, cold are more concerning for cancer
Most common type of thyroid cancer and management (5)
- Papillary
- Resection of gland, iodine ablation, thyroid hormone replacement, whole body scan, serum thyroglobulin (only present if not all thyroid tissue was removed)
Sick euthyroid syndrome
Acute or chronic non-thyroidal illness that is often seen with decreased T3/4 with normal TSH and has no thyroid treatment necessary
