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81 Cards in this Set
- Front
- Back
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what is Thyroxine?
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T4
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what else besides T4/T3 does the thyroid produce?
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Calcitonin
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where does calcitonin come from?
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Follicular C cells
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How is T3 usually utilized?
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Most peripheral tissues utilize T3 converted from T4
Exceptions = brain and pituitary that feed on T3 as source of T3 |
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Kickers for TSH secretion?
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circadian w/ highest levels at night
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what does low iodine lead to?
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deficient thyroid hormone
excess TSH thyroid hyperplasia GOITER |
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What is Thyrotoxicosis?
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Elevated concentrations of free thyroid hormone
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Then what is Hyperthyroidism?
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Excessive release of thyroid hormone by gland hyperfunction
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how to measure iodine uptake?
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RAI
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Pathophys of Graves' disease?
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IgG antibodies bind to and activate TSH receptors on thyroid gland
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what is the most common disorder of thyroid fxn?
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hypothyroid
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most common cause of hypothyroidism?
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iodine def
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what is nongoiterous hypothyroidism?
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degeneration and atrophy of thyroid gland
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how does thyroid hormone affect Growth and Dev?
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Critical for brain dev, so absence for first 6 months of life can lead to MR
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Synthetic T4's?
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Synthroid
Levothroid |
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Synthetic T3's?
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Liothyronine
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Synthetic T4/T3 combo's?
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Liotrox
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SE's of Thyroid Hormone Therapy?
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Allergic Rxn's
Vomiting Chest Pain, Arrhythmias, Dyspnea Tremor HA, insomnia Diarrhea, wt. loss Leg cramps, menstrual irregularites Fever, Sweating, heat sensitivity |
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4 categories of Antithyroid Drugs?
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Synthesis inhibitors (true ATD)
Ionic Inhibitors (block iodide) High Concentrations of Iodide (dec synth/release) Radioactive Iodide (damage gland) |
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Main SE of Synthesis Inhibitors?
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Goitrogenic
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prototype synthesis inhibitor?
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Propylthiouracil (PTU)
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newer, better synthesis inhibitor?
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Methimazole (longer half life, much more potent)
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Downside to methimazole?
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crosses placenta = contraindicated in preggers
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SE's of synthesis inhibitors?
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Rashes
Hives |
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Types of Ionic Inhibitors?
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SCN-***
ClO4-*** NO3 they're similar in size to iodine |
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Interaction for Theiocynate (SCN-)?
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Plant glycosides and smoking increase concentration
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Other goitrogenic drugs?
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Sulfonamides (prevent iodide binding)
Sulfonylureas |
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Drugs that inhibit extrathyroidal T3 generation?
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Glucocorticoids
Propanolol Amiodarone Acetylsalicylic Acid Opiates |
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Other stuff thyroid hormone interact w/?
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Antacids
Iron supplements Warfarin Insulin ERT TCA's |
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who can alter thyroid hormon transport?
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Salicylates
Heparin Dilantin Furosemide Glucocorticoids |
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who inhibits TSH secretion/
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Dopamine agonists
Alpha adrenergic blockers glucocorticoids Acetylsalicylic acid Opiates |
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Synthesis of PTH?
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prepro-->pro in ER-->PTH in golgi
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Roles of PTH?
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stimulate conversion of Vit D to Calcitriol-->
Inc absorption of Ca from intestines and bone Regulates excretion of Ca |
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PTH and phosphate?
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PTH inhibits renal reabsorption of phosphate
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Path of Vit D to get to Calcitriol?
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1. Vit D (cholecalciferol) Synthesized by skin from provitamin
2. Converted to calcifediol in liver 3. Converted to Calcitriol (1,25) in kidney |
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Types of Rickets?
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Nutritional
Metabolic Vit D-dependent Renal |
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Kicker for nutritional rickets?
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Inadequate sunlight or vitamin D
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Kickers for metabolic rickets?
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Abnormal synthesis or response to calcitriol
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kickers for Vitamin D Dependent rickets?
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Auto Rec
Defective conversion of calcifediol to calcitriol |
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Renal Ricket kickers?
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Ass w/ chronic renal failure
Dec conversion to calcitriol |
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who opposes PTH?
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Calcitonin
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where does calcitonin come from?
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thyroid
parathyroid thymus |
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Role of calcitonin?
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it lowers plasma Ca and phosphate
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synthetic calcitonin?
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Cibacalcin used for hypercalcemic pts
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Role of Biphosphonates?
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Inhibit bone resorption by repressing osteoclast fxn
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Examples of Biphosphonates?
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Etidronate**
Pamidronate |
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Indications for Biphosphonates?
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Paget's Disease (skeletal condition leading to disorderd bone mineralization)
Hypercalcemia (good for managing malignancy related) Postmenopausal Osteoporosis |
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how many parathyroids usually?
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4 (80-90%)
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normal size?
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30mg each
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embryology of parathyroids?
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inferior ones: from 3rd branchial pouch
superior ones: from 4th branchial pouch |
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cell types in parathyroid?
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Parenchymal = Chief cells and oncocytes
Stromal = adipocytes |
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Classic Sx and Sx's of Hyperparathyroidism?
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Nephrolithiasis
Osteitis Fibrosa Cystica Neuropsychiatric disorders Peptic Ulcers Pancreatitis Cholelithiasis Muscle weakness/atrophy Metastatic Calcifications |
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What is Osteitis Fibrosa Cystica?
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Osteoclastic bone resorption coupled w/ marrow fibrosis
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what's up with the classic signs and sx's in the US?
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most people never make it that far. they're diagnosed and treated earlier
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Modern (US) signs and symptoms?
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Fatigue, Weakness
Mild Depression many Asymptomatic |
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If its all vague, how are hyper PTH people diagnosed?
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by a routine serum Ca measurement
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Types of Primary HyperPTH?
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Parathyroid Ademoma (80%)
Parathyroid Hyperplasia Parathyroid Carcinoma (rare( |
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Causes of Secondary HyperPTH?
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Parathyroid hyperplasia secondary to:
1) Chronic Renal Insufficiency 2) Vit D Def 3) Intestinal malabsorption of Ca |
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What is Renal Osteodystrophy?
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Combo of Osteomalacia and Secondary HyperPTH
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Pathogenic Mechanisms for Renal Osteodystrophy?
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1) Chronic Renal Failure-->phosphate retention-->dec calcium
2) Renal Damage leads to dec 1alpha-hydroxylase activity-->dec 1,25-(OH)2D--> dec calcium The Dec Calcium --> hyperPTH--> inc Ca mobilization from bone--> demineralization |
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What's up w/ tertiary hyperPTH?
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starts as secondary hyperPTH secondary to renal disease, but PT acquires autonomous fxn leading to persistent hyperPTH and hyperCa
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Rx for tertiary hyperPTH?
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surgical excision
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Causes of HypoPTH?
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Surgical Excision
Congenital Agenesis/hypoplasia Autoimmune Disease |
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clinical features of hypoPTH?
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Inc Neuromuscular Excitability
Emotional Disorders Parkinsonian-like syndromes |
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Parathyroid Tumor Classification?
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ADENOMAS
typical oncocytic water-clear lipoadenoma atypical CARCINOMA SECONDARY metastasis or direct extension |
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B or M for Parathryoid adenoma?
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Benign
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Peak incidence of parathyroid adenoma?
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50-60 years
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gender and parathyroid adenomas?
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3:1
F:M |
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Gross morphology of parathyroid adenoma?
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encapsulated
weigh between .2 and 1 gram often single |
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cellular make up of parathyroid adenoma?
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cheif's
oncocytes mix no adipocytes |
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Mutations leading to Parathyroid Adenoma?
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PRAD1 gets relocated --> overexpression of Cyclin D1 (cell cycle regulator) (40%)
MEN1 Tumor suppressor gene (10-20%) |
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Parathyroid Carcinoma recurrence rate, 5 year, and 10 year survival?
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Recurrence Rate: 30-67%
5 year: 40-86% 10 year: 50% |
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Definitive Features of Parathyroid Carcinoma?
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Invasion (tissues, vessels, perineural)
Metastasis |
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Non-definitive features of carcinoma?
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Mitotic activity
pleomorphism pattern fibrous bands DNA ploidy |
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MEN Syndromes and Parathryoids?
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MEN1 = Parathyroid Adenoma/Hyperplasia
MEN2A = parathyroid hyperplasea |
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What comes w/ MEN1?
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Parathyroid Adenoma/Hyperplasia
Pancreatic Endocrine Tumors Pituitary Adenomas |
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Mutation in MEN1?
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MEN1 at Ch 11 which is an inactivating GERMLINE mutation of a tumor suppressor gene
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What comes w/ MEN2A?
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Parathyroid Hyperplasia
Medullary Thyroid Carcinoma* Pheochromocytoma* |
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Mutations for MEN2 A and B?
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Germline mutation of RET Protooncogene on Ch10
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Inheritance pattern of MEN1 vs 2?
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Both are Auto Recessive
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What comes w/ MEN2B?
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Medullary Thyroid Carcinoma
Pheochromocytoma Mucocutaneous Neuromas |
