Term
| What percent of total Ca is extracellular? How much of that is free? |
|
Definition
| 0.1% is extracellular; 50% of that is free |
|
|
Term
| How do you correct for albumin? |
|
Definition
| For every 1mg/dl decrease in albumin, add 0.8mg/dl to Ca |
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Term
| How does hyperventilation cause numbness? |
|
Definition
| Hyperventilation causes respiratory alkalosis, more Ca is bound, pt is hypocalcemic |
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Term
|
Definition
| Increases Ca reabsorption, activation of vitamin D, bone resorption, increases phosphate excretion |
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Term
| Functions of active vitamin D |
|
Definition
| Increases phosphate and Ca absorption, inhibits PTH secretion, increases bone resorption |
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Term
| How does PTH increase bone resorption? |
|
Definition
| PTH activates osteoblasts to express RANKL, which binds to RANK on monocytes/macrophages, making them differentiate into osteoclasts |
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|
Term
| What enzyme activates vitamin D in the kidneys? |
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Definition
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Term
| Where is CaSR expressed? What is it's second messenger? What drug sensitizes it? |
|
Definition
| On chief cells of parathyroid. IP3. Cinacalset. |
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Term
| Where are PTH receptors located? What is it's second messenger? |
|
Definition
| Renal and bone cells. cAMP. |
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Term
| How is skin, liver and kidney involved in vitamin D metabolism? |
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Definition
| Skin absorbs UVB which is added to 7-dehydrocholesterol to make vitamin D. Liver makes it to 25-OH vitamin D. Kidney makes that into 1,25-OH vitamin D. |
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Term
| How do malignancies cause hypercalcemia? |
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Definition
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|
Term
| Is urinary calcium levels high or low in primary hyperparathyroidism? |
|
Definition
| High because of high Ca filtration, despite increased Ca reabsorption |
|
|
Term
| What lab value is a good measure of Ca stores? |
|
Definition
|
|
Term
| Is vitamin D fat soluble or non fat soluble? |
|
Definition
|
|
Term
| Clinical presentation of hypercalcemia |
|
Definition
| Mostly asymptomatic, nonspecific (fatigue, irritability, dehydration); psychic moans, abdominal groans, bones, and renal stones; respiratory depression and death |
|
|
Term
| Moans groans bones and stones...? |
|
Definition
Moans: depression, fatigue, irritability
Groans: constipation, pancreatitis
Bones: osteoporosis, osteitis fibrous cystic
Stones: polyuris, polydipsia, renal stones, nephrocalcinosis |
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|
Term
| Differential for hypercalcemia (10) |
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Definition
| Primary hyperparathyroidism (MEN syndromes), familial hypocaluric hypercalcemia, tertiary hyperparathyroidism, malignancy, sarcoidosis/TB, adrenal insufficiency, pheochromocytoma, hyperthyroidism, renal failure, drugs (lithium, thiazides diuretics) |
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Term
| High PTH, high plasma Ca, high urine Ca; dx? |
|
Definition
| Primary hyperparathyroidism |
|
|
Term
| Prolactinoma, gastrinoma, hypercalcemia; dx? |
|
Definition
| Primary hyperparathyroidism in MEN1 |
|
|
Term
| Medullary carcinoma of thyroid, pheochromocytoma, hypercalcemia; dx? |
|
Definition
| Hyperparathyroidism in MEN2A |
|
|
Term
| Medullary carcinoma of thyroid, pheochromocytoma, mucosal neuromas, hypercalcemia; dx? |
|
Definition
| Hyperparathyroidism in MEN2B |
|
|
Term
| How do you screen for MEN2 syndrome? |
|
Definition
| Screen for RET proto oncogene |
|
|
Term
| Normal to high PTH, high plasma Ca, low urine Ca; dx? Pathogenesis? |
|
Definition
| Familial hypocaluric hypercalcemia. Loss of function mutation in CaSR |
|
|
Term
| Low PTH, Low plasma Ca, high urine Ca; dx? |
|
Definition
| Gain of function mutation in CaSR |
|
|
Term
| How does lithium cause hypercalcemia? |
|
Definition
| Lithium interferes with IP3 signaling, increasing Ca set point such that a higher plasma Ca is required to turn off PTH |
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|
Term
| Pt with chronic kidney disease presents with hypercalcemia, high PTH; dx? |
|
Definition
| Tertiary hyperparathyroidism |
|
|
Term
| What diseases secrete active vitamin D? (3) |
|
Definition
| Lymphoma, TB, sarcoidosis |
|
|
Term
| How does multiple myeloma cause hypercalcemia? |
|
Definition
| Osteoclasts activating factor |
|
|
Term
| Pt with hypercalcemia and normal PTH, high urine Ca; dx? |
|
Definition
| Malignancy secreting PTH-RP |
|
|
Term
| How does chronic kidney disease cause hypercalcemia? (3) |
|
Definition
| Decreased GFR decreases 1,25OH in plasma causing an increased PTH and bone resorption response. Decreases expression of vitamin D receptors and CaSR. Can cause parathyroid autonomy. |
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|
Term
| Most common cause of active vitamin D deficiency |
|
Definition
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|
Term
| Clinical presentation of hypocalcemia |
|
Definition
| Mostly asymptomatic. Excessive movement, twitches, tetany. Prolonged QT. If chronic: papilledema, cataracts, basal ganglia calcification, dementia, retardation |
|
|
Term
|
Definition
| Maintain BP cuff above systolic pressure for 3 min. Positive Trousseua = strong thumb adduction |
|
|
Term
|
Definition
| Tap facial nerve. Positive Chvostek = facial muscle twitch. |
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|
Term
| Causes of PTH deficiency (6) |
|
Definition
| Surgery, DiGeorge syndrome, autoimmune, irradiation, hypomagnesemia, CaSR gain of function |
|
|
Term
| Short stature, basal ganglia calcifications, mental retardation, cataracts, short 4th metacarpal bones |
|
Definition
| Pseudo hypoparathyroidism |
|
|
Term
| Chronically high PTH, low plasma Ca, high plasma phosphate |
|
Definition
| Pseudo hypoparathyroidism |
|
|
Term
| What is a marker of osteoblastic activity? |
|
Definition
| Serum alkaline phosphatase |
|
|
Term
Type 1 rickets causes...
Type 2 rickets causes... |
|
Definition
1. Vitamin D deficiency
2. Vitamin D resistance |
|
|
Term
| 3 causes of vitamin D deficiency |
|
Definition
| Kidney disease, diet, type 1 rickets |
|
|
Term
| In pts with chronic renal failure, hypocalcemic is likely due to? |
|
Definition
| Reduced absorption of phosphate and Ca |
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