Lect 5 Flashcards
PTH effects on Ca and phos
increase in serum Ca
decrease in serum phos
Vit D effects on Ca and phos
increase in serum Ca
increase in serum phos
Calcitonin
decrease in serum Ca
decrease in serum phos
loss of nephrons
increased phos retention
decreased prod of 1,25 DH D3
secondary hyperparathyroidism
HD pts= PTH >495 pg/mL assoc w/ increased sudden death, increased morbidity and mortality
corrected Ca
Ca(corr)= [(4-albumin) x 0.8] + Ca(obs)
soft tissue calcification
rate is high when Ca x P >70 mg2/dL2
uncommon below 50 mg2/dL2
recommended to maintain below 55 mg2/dL2
elevated Ca x P assoc with ___
vascular calcification, CV disease, calciphylaxis, death
reference range of Ca
8.5-10.5
goal Ca for CKD stages
for all stages= w/in reference range
hypocalcemia
serum Ca less than 8.5
sx of hypocalcemia
depend on acuity of onset
acute= neuromuscular, CV
chronic= CNS, dermatologic
WHAT MEDS COMMONLY CAUSE HYPOCALCEMIA?
bisphosphonates, calcitonin, furosemide, oral phosphorus therapy
common causes of hypoCaemia
ICU, elderly, malnourished, pts who have received sodium phos as bowel prep, Vit D deficiency, parathyroidectomy or thyroidectomy, drugs
treatment for acute, symptomatic hypocalcemia
100-300 mg elemental Ca IV over 5-10 min (should not be infused faster than 60 mg/min due to cardiac dysfunction)
treatment for asymptomatic hypocalcemia
oral calcium 1-3 g/day
correct underlying cause if possible (replace Mg, replace Vit D)
treatment for acute, symptomatic hypocalcemia
100-300 mg elemental Ca IV over 5-10 min (should not be infused faster than 60 mg/min due to cardiac dysfunction)
continuous infusion 0.5-2 mg/kg/hr elemental Ca
treatment for asymptomatic hypocalcemia
oral calcium 1-3 g/day
correct underlying cause if possible (replace Mg, replace Vit D)
hypercalcemia
serum Ca >10.5 mg/dL
sx of hypercalcemia
Ca less than 13= asymptomatic
Ca >13= depends on acuity of onset
acute= anorexia, N/V, constipation, polyuria/dipsia; hypercalcemic crisis (acute elevation to >15 mg/dL)
chronic= metastatic calcification, nephrolithiasis, chronic renal insuffienciency
sx of hypercalcemia
Ca 13= depends on acuity of onset
acute= anorexia, N/V, constipation, polyuria/dipsia; hypercalcemic crisis (acute elevation to >15 mg/dL)
chronic= metastatic calcification, nephrolithiasis, chronic renal insuffienciency
common causes of hyperCaemia
malignancy, primary hyperparathyroidism, meds
common drug causes of hyperCaemia
Vit D analogs, Ca supplements, lithium
tx for hyperCaemia
- rehydration with NS 200-300 mL/h
- loop diuretics: furosemide 40-80 mg IV Q1-4h
- calcitonin 4 units/kg SQ or IM Q12h (use when hydration is C/I)= use in hemodialysis or ESRD
- bisphosphonates: zoledronate 4-8 mg IV given over 5 min
hypophosphatemia causes
decreased GI absorption (phos binders, sucralafate)
increased urinary excretion
extracellular to intracellular redistribution (refeeding syndrome)
hypophosphatemia symptoms
mild-mod= aysymptomatic severe= arrhythmias, resp muscle fatigue/ failure, myalgias, weakness, coma
treatment for severe symptomatic hypophosphatemia
phos 15-30 mmol IV over 3 hours
causes of hyperPhosemia
renal failure
intracellular phos release (tumor lysis syndrome)
sx of hyperphosphatemia
soft tissue calcification
N/V, diarrhea, lethargy, seizures
renal osteodystrophy
phos restriction
restrict to 800-1000 mg/day when:
phos levels >4.7 mg/dL
plasma conc of PTH elevated above target
reference range for phos
2.6-4.5
calcium citrate
phos binder
not to be used concurrently w/ aluminum-based binders
aluminum-based phos binders
slowly removed by dialysis so can accumulate in various tissues
toxicity treated with deferoxamine
aluminum-based phos binders
slowly removed by dialysis so can accumulate in various tissues
toxicity treated with deferoxamine
when are non-Ca, non-Mg, non-Al based binders first line?
when hypercalcemic, low PTH, or vascular calcification
examples of non-Ca, non-Mg, non-Al based binders
- sevelamer HCl (Renagel)= lowers LDL, increases HDL; should not be broken or chewed
- lanthanum carbonate (Fosrenol)= chewable wafer
when is it ok to use aluminum-based binders?
in pts with phos >7 mg/dL, they may be used for less than 4 weeks
Stage 3 & 4 phos binders first line
calcium-based
Stage 5 primary phos binder therapy
either calcium-based binders OR non-Ca, non-Mg, non-Al based binders
can use combo if monotherapy ineffective
stage 5 use of calcium binders
total daily dose of elemental Ca should not exceed 2 g/day (1500 mg phos binder, 500 mg diet)
when do you start a Vit D COMPOUND in CKD?
Stage 3 or 4
when serum conc of 25-hydroxyvitamin D is less than 30
when do you start a Vit D STEROL in CKD?
serum conc of 25(OH)D less than 30 and PTH is above target range
when PTH is progressively increasing and remain persistently higher than the upper reference limit
only in pts with Ca and phos at goal
do not use in rapidly worsening kidney function or non-compliant
when is it ok to use aluminum-based binders?
in pts with phos >7 mg/dL, they may be used for
which Vit D therapies are compounds?
ergocalciferol and cholecalciferol
which Vit D therapies are sterols?
calcitriol, paricalcitol, doxecalciferol
ADR’s of Vit D tx
increased intestinal absorption of Ca and phos (can lead to hyperCaemia or aggravate hyperPhosemia)
decreased PTH –> adynamic dbone disease
when do you start a Vit D COMPOUND in CKD?
Stage 3 or 4
when serum conc of 25-hydroxyvitamin D is
when do you start a Vit D COMPOUND in CKD?
Stage 3 or 4
when serum conc of 25-hydroxyvitamin D is
when do you start a Vit D STEROL in CKD?
serum conc of 25(OH)D target range
when PTH is progressively increasing and remain persistently higher than the upper reference limit
only in pts with Ca and phos at goal
do not use in rapidly worsening kidney function or non-compliant
PTH reference ranges
Stage 3-5= 35-70
Stage 5 dialysis= 130-600
calcimimetics (cinacalet HCl)
decrease PTH secretion and Ca x P
majority of pts receiving concurrent Vit D and phos binders
ADR’s of calcimimetics
N/V, hypoCaemia
inhibitor of CYP2D6
take with meals
calcimimetics place in therapy
alternative or adjunct to Vit D analogs
