Clin Med - Exam 8 - Thyroid
Hyperparathyroidism: - Etiology
1° (Parathyroid Gland) - 4-gland hyperplasia 2° (Pituitary) - Hypercalcemia 3° (Hypothalamus) - d/t long-standing 2° Single Adenoma (80%) - Left inferior gland MC - Inferior glands are more predictable location Hyperplasia (10-15%) Cancer (<1%)
Adrenal Labs: - Low cortisol w/ ↑ ACTH
1° Adrenal insufficiency (Addison's)
Adrenal Labs: - Low cortisol w/ ↓ ACTH
2° Adrenal insufficiency (Hypopituitary)
Hyperparathyroidism: - Manifestation
No or mild Sx Nephrolithiasis: - 15-20% new Dx Pts Fatigue Muscle weakness Mild ↓ cognition (w/ Ca >11)
Hashimoto's Thyroiditis: - Tx
TH Replacement: - Levothyroxine (T4) - Liothyronine (T3) - Armour thyroid (T3&T4) Careful w/ elderly Pts Goal: TSH <2
Addison's Disease: - Tx
r/o TSH problems, but treat adrenal insufficiency first
What thyroid cancer spreads through the blood?
Follicular
Which thyroid cnacer has ↑ calcitonin?
Medullary
Thyroid Dx: - Nodule Workup
*FNA:* - Positive = resection - Suspicious = recection (4% end up being carcinoma) - Negative = re-biopsy *TFT:* - ↓ TSH w/ nodule = uptake & scan - ↑ TSH w/ nodule = hypothyroid Tx *Thyroid Uptake & Scan:* - "Hot" nodule = positive test - "Cold" nodule = negative test
Thyroid Dx: - TFT
*Hormones:* - TSH - Free T3 - Free T4 *Antibodies:* - TSI (Thyroid Stimulating immunoglobulin) - TPO (Thyroid Peroxidase Antibody) - ATA (Antithyroglobulin antibody)
When do you use I-131 to treat thyroid cancer?
*Papillary:* - Multifocal - Lesion > 1cm *Follicular:* - Lesion > 1cm
Important for Ca++ regulation
*Parathyroid:* - Bone strength - Muscle function - Nerve function
Adrenal Insufficiency: - 1° vs 2°
*Primary (Addison's):* - Adrenal gland damage - ↑ ACTH w/ ↓ Cortisol +/- ↓ Aldosterone - *Negative rapid ACTH stim test* *Secondary:* - Pituitary damage - ↓ ACTH w/ ↓ Cortisol - *Positive rapid ACTH stim test*
Addison's Disease: - Labs
ACTH > 250 pg/ml CMP: - Hyponatremia - Hyperkalemia - Hypercalcemia - Hypoglycemia - Mild non-AG met acidosis Urinary & Sweat Na+ LFT CBC: - Anemia masked by dehydration
Addison's Disease: - Pathophysiology
Adrenal gland damage ↓ Decreased cortisol & aldosterone
Adrenal Labs: - High cortisol w/ ↓ ACTH
Adrenal gland tumor
Surgery, XRT, and chemo do not work for which type of thyroid cancer?
Anaplastic
Which thyroid cancer is lethal within 6wks - 3months?
Anaplastic
Hyperthyroidism: - Manifestation
Anxious Bulging eyes Weight loss Fatigue Tachycardia Sweating Insomnia Diarrhea
Hashimoto's Thyroiditis: - Pathophysiology
Autoimmune disorder ↓ Hyperthyroidism ↓ Thyroid fatigue ↓ Hypothyroidism
Graves Disease: - Pathophysiology
Autoimmune disorder ↓ Overproduction of TH
Hyperparathyroidism: - Tx
Bisphosphonates: - Fosamax - Actonel - Boniva Surgery: - Remove adenoma - Remove 3 glands for hyperplasia
Thyroid Dx: - US
Can detect nodules >0.2cm Diagnostic for nodules >1cm - 4% CA in female - 7% CA in males Also used to guide FNA
Hyperparathyroidism: - Pathophysiology
Elevated PTH ↓ Elevated bone resorption ↓ Hypercalcemia Affects compact > trabecular bone Cortices of long bones are affected more
Cushing's Syndrome: - Pathophysiology
Excess cortisol: - Corticosteroid medication (MC)
Graves Disease: - RF
Female > Male
Thyroid Dx: - FNA
Fine Needle Aspiration More accurate for cancer Dx than any other test for uni-nodular lesions. - 80% sensitivity - ~100% specificity - <6% False neg/pos
Aldosterone
Function: - Na+ reabsorption - K+ excretion - ↑ BV Stimulated by: - High serum K+ - Low BV (angiotensin II)
Adrenal Gland: - Products
Glucocorticoid (cortisol) Androgen (DHEA) Mineralocorticoid (aldosterone)
Hashimoto's Thyroiditis: - Manifestation
Goiter Birth defects Heart problems ↑ LDL *Myxedema*
Positive TSI indicates
Graves disease
MC cause of hypothyroidism
Hashimoto's Thyroiditis
Graves Disease: - Manifestation
Heart disorders Brittle bones Thyroid Storm *Exophthalmos*
Graves Disease: - Dx
Hormones: - ↓ TSH - ↑ TH Auto-Ab: - *TSI* - TPO - ATA Uptake & Scan: - Diffuse "hot"
Hashimoto's Thyroiditis: - Dx
Hormones: - ↓ TSH (hyper) → ↑ TSH (hypo) - ↑ TH (hyper) → ↓ TH (hypo) Auto-Ab: - TPO - ATA (*NO TSI !!!!!*)
Thyroid Dx: - Thyroid Uptake & Scan:
Hot = ↑ uptake = ↑ activity (hyperthyroid) Cold = ↓ uptake = ↓ activity (hypothyroid)
Which thyroid cancer is associated w/ a Hx of a goiter?
Lymphoma
What is the MC & 2nd MC thyroid cancer?
MC: Papillary 2nd MC: Follicular
What thyroid cancer spreads through the lymphatics?
Papillary
Which thyroid cancer can be multifocal?
Papillary
Adrenal Labs: - High cortisol w/ ↑ ACTH
Pituitary tumor
Cushing's Syndrome: - Tx
Surgery at source: - Adrenal - Pituitary Medication: - d/c steroids - Cortisol replacement after Tx
Graves Disease: - Tx
Radioactive iodine Propylthiouracil (PTU) - Block TH production - Inhibit conversion T4→T3 Methimazole (Tapazole) - Block TH production Beta blocker Surgery
Thyroid Storm / Thyrotoxic crisis
Rare, life-threatening complication of Grave's disease Requires immediate emergency care Manifestation: - Fever - Diaphoresis - Confusion - Delirium - Weakness - Tremors - Irregular heartbeat - ↓ BP - Coma
Myxedema
Rare, life-threatening complication of Hashimoto's disease Requires immediate emergency care Long-term hypothyroidism ↓ Cold intolerance & drowsiness ↓ Profound lethargy & unconsciousness ↓ Coma
Hypothyroidism: - Manifestation
Tired Fatigue Weight gain Brittle hair Brittle nails Constipation Long heavy menses Cold intolerance
Rapid ACTH Stim Test
Uses *Cortrosyn* to test function of the adrenal gland: - Should ↑ cortisol secretion from adrenal gland when administered *Positive test = ↑ cortisol w/ Cortrosyn admin = functional adernal gland = 2° adrenal insufficiency* *Negative test = no Δ cortisol w/ Cortosyn admin = non-functioning adrenal gland = 1° adrenal insufficiency* *2 Criteria for positive test:* - ↑ Cortisol by ≥ 20 mcg/dl in 30-60 minutes - ↑ Baseline cortisol level by ≥ 7
Addison's Disease: - Imaging
X-ray: +/- small heart CT: +/- adrenal gland atrophy EKG: - Low voltage QRS - Non-specific ST/T waves - d/t hyperkalemia
