01-17 Hyperthyroidism Flashcards
Learning objectives
What is the difference between thyrotoxicosis, hyperthyroidism, and hyperthyroxinemia?
- Thyrotoxicosis: state in which tissues are exposed to and respond to an excess of thyroid hormone.
- Hyperthyroidism: hyperfunction of the thyroid gland with resultant thyrotoxicosis.
- Hyperthyroxinemia: elevated measurable thyroid levels in the blood
What are the symptoms of hyperthyroidism?
—Nervousness —Fatigue —Weakness —Increased Sweating —Heat Intolerance —Altered Sleep —Irritability —Tremor Hyperactivity —Palpitations (5% A. fib pts have Graves') —Increased appetite —Weight loss (rare weight gain) —Menstrual Disturbances —# stools/day and/or diarrhea
What are the clinical findings (signs, labs, imaging) of hyperthyroidism?
SIGNS —Hyperactivity —Tachy/Atrial Arrhythmias (↑ # β-Rs & ↓ α-Rs) —Systolic HTN —Warm, moist skin, —Stare/Eyelid retraction —Tremor —Hyperreflexia —Muscle Weakness (b/c catabolic state)
LABS
—low TSH is diagnostic
—can also do Total and/or Free T3 and/or T3
IMAGING (if unsure)
—Iodine uptake/Scan: ↑ uptake →
Graves' disease —Etiology —P.E. Findings —Lab/Imaging findings —Tx
ETIOLOGY
—Ab produced that mimics TSH (many postulated Ag’s)
—Lymphocytic Infiltration of thyroid (T-cell mediated; B-cells w/in and outside thyroid make Abs)
P.E. FINDINGS
—Homogeneous, diffusely enlarged gland
—Vascular Goiter with possible hums/bruits
—Graves’ Triad: 1. Diffuse Hyperplasia
2. Infiltrative Opthalmopathy (Exopthalmus) 3. Infiltrative Dermopathy (pretibial myxedema)
LAB FINDINGS
—Iodine uptake and scan
—Maybe TBII (TSH-binding inhibitory Ig) levels
TX —Betablockers —Antithyroid drugs (PTU and Tapazole) —Radioiodine Ablative Therapy —Surgery
EXOPTHALMUS TX —Eye drops---Artificial Tears —Steroids---Dexamethasone —Surgical Decompression of Orbits —Radiation Therapy
Toxic Multinodular Goiter —Etiology —P.E. Findings —How to Dx —Tx
2nd MOST COMMON CAUSE OF HYPER-THYR
TMNG ETIOLOGY
—Several mechs postulated about abnl growth
P.E. Findings
—multiple nodules
—same as other thyrotoxicoses excluding Graves’ unique findings
DX
—PE and/or nuclear scan/uptake or thyroid US
TX —beta blockers —antithyroid medication —surgery —Radioiodine Ablative Therapy
toxic thyroid adenoma
—Description: Single “hot” nodule on nuclear scan representing an area of thyroid autonomy
—Features: Almost always benign; Occasionally assoc w/ T3 toxicosis
—Remainder of the gland is suppressed and often difficult to palpate
Define Excess TSH secretion (Pituitary tumor) —Etiology —P.E. Findings —Labs —Imaging —Tx
[This is a rare condition]
ETIO
—TSH-secreting adenoma
P.E. —big, homogeneous thyroid —bilateral hemianopsia —no s/sx of Graves' —may hear bruit over thyroid
LABS
—inappropriately high TSH (usu down w/ hyper)
IMAGING
—get MRI of head
TX
—Surgery and/or radiation for macroadenomas
—Octreotide acetate
—–longacting somatostatin analogue
—–lowers TSH levels
—–tumor shrinkage and possible visual field improvement
Define Thyrotoxicosis factitia
—Description
—Dx
—Tx
DESCRIPTION
—o/d on pills; often healthcare workers who want to lose wt.
DX
—Labs: ↑ T4 & T3 w/ ↓ TSH
—Nuc Uptake Scan: 0% uptake (even thyroiditis pts have 0.5-3%)
TX
—confront patient & involve psych PRN
—stop hormone
What is the Graves’ triad?
diffuse thyroid hyperplasia, ophthalmopathy, dermopathy
What are the Gravs’ Igs?
TSI and TBII (TSH-binding inhibiting immunoglobulins)
PTU & Methimazole
—Rx for short or long term therapy
—can only be used in autonomous situations
—Minor ADRs: rash, LFT abnl, arthralgias
—Major ADRs: Neutropenia is rare <1% reversible, more common in elderly and high doses
Tapazole
Brand name methimazole
Thyroid ablation —Agent —Desired Outcome —Preparations —ADRs
AGENT
—I-131
DESIRED OUTCOME
—Definitive Therapy; Hypothyr is desired
PREP:
—Iodine uptake scan, estimate gland size, stop antithyroid drugs (PTU), higher doses may be required in TMNG/elderly
—ADRs: Radiation Thyroiditis, Thyroid Storm; No known carcinogenic effect
Most common forms of Thyrotoxicosis?
—Mechanism?
—Autonomous?
In order of prevalence:
- Graves’ (TSH-R Ab; non-autonomous)
- Multinodular Goiter (Foci of fxn autonomy; auton)
- Toxic adenoma (Benign tumor; autonomous)
Thyroiditis in cause 5-10% of time
HLA overlap between Graves’ and?
Hashimoto’s (ironically)
—Also, pernicious anemia, 1° thyroid failure, and other autoimmune disease
