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42 Cards in this Set
- Front
- Back
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how much of total body Ca++ is extracellular?
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0.1%
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Where does PTH act?
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Bone
Kidney Gut |
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To what does Ca++ bind to the parathyroid in the feedback mechanism?
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CaSR (Ca Sensing Receptor)
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what is resorption of bone?
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breaking bone down to create free Ca++ in the serum
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What does calcitonin do?
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antagonizes PTH (lowers Ca++)
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What is a helpful pneumonic for sx of hypercalcemia?
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Serendipity, Stones, Bones, Groans, and Psychiatric Overtones
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What are some sx of severe acute hypercalcemia?
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anorexia
polyuria dehydration impaired mentation immobilization |
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T or F: Longstanding asx hyperCa++ is more likely to be primary hyperparathyroidism than cancer
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TRUE
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What is the cutoff for mild hypercalcemia?
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< 11 mg/dL (usually 1'ary hyperparathyroidism)
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What is the threshold for severe hyperCa++?
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> 13 mg/dL (usually malignancy-associated)
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What are some non-PTH mediated causes of hyperCa++?
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Vitamin D (nonmalignant - sarcoid producing 1,25(OH)2-D)
Malignancy Meds (lithium, thiazide, PTH) Misc. (milk-alkali syndrome, endocrine) |
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inappropriately "normal" or high PTH w/ hypercalcemia --> __ mediated
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parathyroid
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inappropriately "normal" or high PTH, hyperCa++, low 24 hr urine Ca++ -->
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Familial Hypercalcemic Hyperparathyroidism (mutation of CaSR)
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How do you Rx FHH (CaSR mutation)?
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observation
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inappropriately "normal" or high PTH, hyperCa++, high 24 hr urine Ca++ -->
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some kind of hyperparathyroidism
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explain the pathophysiology of 2'ary hyperparathyroidism.
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Chronic kidney dz --> low 1,25(OH)2-D and low Ca++ --> ++PTH
This is a good thing! |
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What is tertiary hyperparathyroidism?
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autonomous overproduction of PTH
usually have chronic kidney dz +/- tranx |
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A young pt presenting w/ hyperCa++ and hyperparathyroidism...what do you need to think about?
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familial HPTH Jaw tumor syndrome
MEN syndromes FHH |
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HyperPTH, HyperCa++, hypocaluria -->
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FHH
TEST 1ST DEG RELATIVES Ca++ |
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What are the 3 P's of MEN1?
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HyperParathyroid tumor, Pituitary tumor, Pancreatic tumor
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What is the pneumonic for MEN2A?
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MPH --> MTC, Pheo, Hyperparathryoidism
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What is the pneumonic for MEN2B (MEN3)?
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MPM --> MTC, Pheo, Mucosal neuroma/Marfanoid habitus
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What is McCune Albright syndrome?
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PTH "excess" caused by constitutively active G protein (GNAS)
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Cafe-au-lait lesions w/ "coast of Maine" border that respects midline -->
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McCune Albright
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cafe-au-lait, precocious puberty, fibrous dysplasia -->
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McCune Albright
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What are some endocrine causes of mild hyperCa++?
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Hyperthyroidism
Adrenal Insufficiency Pheochromocytoma VIPoma |
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High Ca++, low PTH, nl-low 1,25-D and high PTHrp -->
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hyperCa++ of malignancy
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High Ca++, low PTH, and high 25-OH-D -->
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Vitamin D intoxication
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High Ca++, low PTH, high 1,25-(OH)2-D -->
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Granulomatous or lymphoproliferative d/o
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How do you Rx hyperCa++ of malignancy?
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hydration, diuretics, bisphosphonates, tx cancer
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What are some sx hypoCa++?
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agitation
hyperreflexia convulsions HTN long QT |
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What is Trouseau's sign?
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inflate BP cuff > systolic BP to occlude brachial artery
pts w/ hypoCa++ will have carpal-pedal spasm |
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What is Chvostek's sign?
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tapping of the inferior portion of the zygoma will produce facial spasms in pts w/ hypoCa++
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HypoCa++ w/ high PTH...what's the DDx?
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Vit D deficiency or resistance
PTH resistance pseudohypoparathyroidism Renal dz acute pancreatitis |
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How does magnesium fit in to calcium homeostasis?
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hypoMg can cause hypoCa++ by producing PTH resistance and by suppressing the secretion of PTH (in severe hypoMg)
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Low PTH, Nl Mg++ -->
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hypoparathyroidism
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High PTH, normal Vit D -->
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pseudohypoparathyroidism (renal dz, Albright's dz)
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What causes Albright's Hereditary Osteodystrophy?
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Loss of function mutation in GNAS --> PTH has no effect
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what are some sx of maternal inheritance of Albright's?
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OBESITY
hypoCa++ due to PTH resistance skeletal phenotype |
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What are some sx of paternal inheritance of Albright's?
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PSEUDOPSEUDOHYPOPARATHYROIDISM
skeletal phenotype |
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What is the action of Vitamin D on the kidney?
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increases Ca++ and phosphorus reabsorption
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what are the 3 most common causes of hypoCa++?
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postsurgical hypoparathyroidism
AI hypoparathyroidism Vitamin D deficiency |
