Endocrine Flashcards
(46 cards)
Thyroid Gland
Free and total thyroid
T4/T3
Primary effects:
Metabolism
Temperature management
Growth & Development
Hypothyroidism – Signs and Symptoms
Increased weight gain
Cold intolerance
Hair loss
Hypothyroidism treatment
Supplementation
-T4 (Levothyroxine) Synthroid ®
-T3 (Liothyronine) Cytomel®
-T4/T3 Combination - Armour Thyroid®
Long half-life of T4 (7-10 Days)
Onset of action:
-initial 3-5 days
-peak 4-6 weeks
Hashimoto’s Disease
Most prevalent
Inherited with unknown gene expression
Women>Men
40-60 years of age
Immune cells target and destroy thyroid tissue
Myxedema Coma
Severe form of hypothyroidism
No edema/no coma
Deteriorating mentation
Myxedema Coma treatment
Supportive care
IV levothyroxine
Reverse underlying cause if known
Hyperthyroidism – Signs and Symptoms
Atrial Fibrillation, Muscle Weakness, Heat Intolerance, neck swelling (Goiter)
Hyperthyroidism treatment
Propylthiouracil (PTU) - Blocks synthesis of new thyroid hormone, prevents conversion of T4 to T3
Methimazole - Block synthesis of new thyroid hormone
Graves Disease
Autoimmune disorder
-Hyperthyroidism
Rapid/irregular heart rate
Osteoporosis
Muscle weakness
Vision changes
Weight loss
Thyrotoxicosis – Umbrella Term
1% prevalence, Most common cause is Graves Disease (Autoimmune disease)
Of that population – 1% will experience thyrotoxicosis crisis “Thyroid Storm”
Extremely elevated T4 and T3
20% mortality rate
Thyrotoxicosis - Treatment
For Symptomatic Relief, beta blockers (propranolol, slows everything down and only used for symptom relief in this case)
Antithyroid agents (PTU or methimazole)
Other therapies
-Radioactive iodine
-Thyroidectomy (hypothyroidism is a concern after this)
Iodide
Blocks new hormone synthesis & release
Tachyphylaxis ~2 weeks
Parathyroid
Parathyroid Hormone (PTH)
Maintains calcium homeostasis
Hypoparathyroidism
Poor PTH secretion
Reduced bone resorption – hypocalcemia
Supplement
-Calcium & Vitamin D
Hyperparathyroidism
Excessive PTH secretion
-Tumors
-Hypercalcemia
Resection
Vitamin D
Supports bone mineralization
Calcitriol stimulates calcium absorption from the GI tract
Decreases PTH, promoting bone mineralization by decreasing catabolic effects of PTH
Calcitonin
Secreted by thyroid
Stimulated bone formation -> increases incorporation of calcium into skeletal storage
Bisphosphonates
often first line in therapy for bone mineralization homeostasis, inhibits osteoclastic activity
Side effects: GI upset, abdominal pain, nausea, flu-like symptoms
Rare side effects: Atypical fractures, osteonecrosis of the jaw (ONJ), bone/muscle/joint pain
Atypical Fractures
Subtrochanteric & diaphyseal femur fractures
Can be bilateral
Higher risk patients: long term therapy, Asian race, steroid use >1yr, femoral bowing
Prodrome of pain in weeks or months prior
Osteonecrosis of the Jaw (ONJ)
Destruction and death of bone that affects the mandible
Most cases reported are with patients on bisphosphonates
Higher risk patients: Cancer, longer duration of therapy, concurrent steroid use
Calcium
Supplements calcium to maintain adequate levels for bone formation
*Dietary is preferred source
*Target RDA based on patient specific factors
*Hypercalcemia is harmful
Vitamin D analogs
Enhance bone formation by increased absorption of calcium
*Fat soluble vitamin = toxicity risk
*Weekly or daily dosing
Adrenocorticosteroids
Cholesterol backbone
Glucocorticoids
-Cortisol (glucose metabolism)
-Inflammation
-Immune system
Glucocorticoids
Receptor binding
Extra & Intra-cellular
-DNA expression
-Protein synthesis
Increase in glucose
-Liver
-Increased storage (glycogen)
Muscle/Adipose Tissue
-Increased breakdown
-Decreased storage
Immune system suppression
