Chapter 1 Flashcards
(31 cards)
Regulators of calcium
Bone
GI
Kidneys
Stimulators of PTH secretion
decreased serum Ca
Mild decreases in serum magnesium
Increases in serum phosphorus
Inhibitors of PTH secretion
Increase in Calcium
Severe decreases in magnesium
Calcitriol
how to adjust calcium for albumin
For every 10 below normal for albumin (40), increase serum calcium by 0.2
Degrees of hypercalcemia
2.5-3; mild
3-3.5; moderate
>3.5 severe
Approach hypercalcemia
PTH vs non PTH mediated Non PTH mediated; -CA; humoral vs osteolytic hypercalceia -Vit D mediated -Genetic (FHH)
Humoral hypercalcemia
PTHrp -squamous cell -adenoCA (breast, ovary) -RCC -transitional cell carcinoma (bladder) **when present likely means high tumor burden since each cell only secretes small amount PTHrp Calcitriol -secreted by B cells in lymphoma (less common)
Osteolytic hypercalcemia
due to invasion of bone; multiple myeloma, adenoma breast, some lymphomas
Vitamin D mediated
-Granulomatous disease; TB, sarcoid
-Endocrine; thyrotoxicosis (increased bone turnover), primary adrenal insufficiency (decrease vascular volume and calcium clearance), phew (produces PTHrp)
-prolonged immobilization
Drugs: thiazide diuretics, lithium, vit D
Treatment hypercalcemia
- IVF
- Lasix
- bisphosphonates
- Calcitonin
- steroids
Bisphosphonates
inhibits osteoclast effects
- great affinity for bone and resistant to degradation effects which account for their long half life
- poor absorption GI so IV route necessary
- effect begins within 2 days and nadir 7 days
- can last several weeks to months
Calcitonin
- inhibits bone resumption and increase real excretion of calcium
- onset 4-6 hours, nadir 12-24 hours
- not as effective as calcium lowering agent as bisphosphonates but is faster onset when dealing with dangerously high levels of calcium (>4)
- tachyphylaxis develops in 48-72 hours
Steroids in treatment hypercalcemia
- Only effective if hypercalcemia mediated by hematologic cancers (lymphoma or MM) or granulomatous diseases
- give equivalent of hydrocortisone 2-300 mg/day IV 3-5 days
Calcium >3.5 asymptomatic
could use IVF + bisphosphonates vs calcitonin
Calcium >3.5 symptomatic
IVF + calcitonin +/- bisphosphontes +/- steroids
EKG hypercalcemia
Shortening QT
Osborn (j) waves; positive deflection at J point (also see in hypothermia)
Ventricular irritability and VF arrest
EKG hypocalcemia
QT prolongation
Dysrrhythmias uncommon
Hypocalcemia values
- 2-2.6- mild
1. 9-2.2 niderate
Sx hypocalcemia
Increased neuromuscular irritability; tetany
Chovstek
Trousseau
Perioral and fingertip parasthesia
Spontaneous muscle cramps
Feared: contraction of respiratory and laryngeal spasm
Approach hypocalcemia
PTH abnormalities (low PO4)
- hypoparathyroidism; surgery, radiation, autoimmune (polyglandular autoimmune syndrome, infiltrative
- functional hypopara: Mg deficiency
- PTH resistance; pseudohypoparathyroidism
Vitamin D abnormalities (High PO4)
- Vit D deficiency; nutritional, malabsorption
- Altered vit D metabolism: cirrhosis, CKD
Drugs
-calcitonin, bisphosphonates, plicamycin, loop diuretics
Acute causes: pancreatitis, rhabdomyolysis, tumor lysis syndrome, transfusion blood products (citrate), toxic shock syndrome
Others: malabsorption, hypoalbuminemia
Treatment Hypocalcemia (severe)
IV; calcium gluconate preferred over calcium chloride due to less tissue necrosis if extravasated
- 1-2 grams calcium gluonate administered over 10-20 minutes (faster administration can result in prolonged QT)
- Infusion cannot contain bicarb or phosphate because can precipitate into insoluble calcium salts
Anti-Ro, Anti-La also known as SS-A and SS-B
Sjogren’s syndrome
Anti-Smith
Lupus
- 99% people with autoantibody have disease, but only 20% pts with SLE have anti-smith
- associated with CNS involvement, kidney disease, lung fibrosis and pericarditis but not associated with disease activity
Anti-nRP/anti-U1-RNP
Highly associated with mixed connective tissue disease
