I. Pathophysiology

  1. Primary: Decreased Glomerular Filtration Rate
    1. Hypocalcemia
      1. Decreased Vitamin D activity and deficiency with decreased calcium absorption
    2. Hyperphosphatemia
      1. Phosphate retention
  2. Secondary Hyperparathyroidism
    1. Contrast with Primary Hyperparathyroidism (where calcium is increased and phosphate low)
    2. Results in increased Osteoclast activity and increased bone turnover
  3. Ultimate bone impacts
    1. Oseteomalacia
    2. Osteitis Fibrosa Cystica

II. Labs

  1. Serum Phosphate
  2. Serum Calcium
  3. Parathyroid Hormone
  4. 25-Hydroxyvitamin D
    1. Also increases PTH
    2. Replace if <30 ng/ml

III. Management: Parathyroid Hormone (PTH) target

  1. Target Parathyroid Hormone
    1. Stage 3: 35-70 pg/ml
    2. Stage 4: 70-110 pg/ml
    3. Stage 5: 150-300 pg/ml
  2. Initial Steps: Measures to suppress PTH Secretion
    1. Treat Hyperphosphatemia
    2. Give Calcitriol
    3. Give Vitamin D Analogs
  3. Persistent rise in PTH despite initial steps
    1. 25-OH-Vitamin D <30 ng/ml
      1. Replace with Ergocalciferol or Cholecalciferol
    2. 25-OH-Vitamin D >30 ng/ml: Give Cacitriol (if calcium <9.5, phosphorus <5.5, CaxPO4 <55)
      1. PTH 70-300 (ckd3) or 110-300 (ckd4) Calcitriol 0.25 mcg/day
      2. PTH 300-600: Calcitriol 0.5 to 1.0 mcg/day
      3. PTH 600-1000: Calcitriol 1 to 2 mcg/day
  4. Persistent rise despite above in Dialysis patients
    1. Calcimimetic: Cinacalcet (Sensipar)
      1. Suppresses PTH by increasing Parathyroid Gland's calcium-sensing receptor sensitivity

IV. Management: Phosphate

  1. Serum Phosphorus Target
    1. Stage 3-4 CKD: 2.7 to 4.6 mg/dl
    2. Stage 5 CKD: 3.5 to 5.5 mg/dl
  2. Dietary phosphate restriction
    1. Limit phosphate to 800-1000 mg/day
    2. Indication
      1. PTH increased
      2. Phosphate levels >4.6 mg/dl
  3. Phosphate binders
    1. Calcium Carbonate (Tums)
    2. Sevelamer (Renagel)
    3. Calcium Acetate (PhosLo)
  4. Avoid
    1. Calcium Citrate (citracal)
    2. Aluminum based binding agents (due to aluminum deposition in bone)

V. Management: Calcium

  1. Serum Calcium and Serum Phosphate Target
    1. Keep Ca x PO4 <55
  2. Keep total calcium 8.4 to 9.5
    1. Maximum Dietary Calcium 2000 mg/day (including calcium based binders)
  3. Total Serum Calcium <8.4 (or PTH>55)
    1. Oral Calcium supplement
    2. Oral Vitamin D
    3. Calcitrol (Rocaltrol) 25 mcg every other day
  4. Total Serum Calcium >9.5 or PTH below goal
    1. Discontinue Calcium Supplementation
    2. Avoid calcium-based phosphate binders
    3. Avoid Vitamin D

VI. Complications

  1. Osteitis Fibrosa Cystica

Images: Related links to external sites (from Google)

Ontology: Renal Osteodystrophy (C0035086)

Definition (MSH) Decalcification of bone or abnormal bone development due to chronic KIDNEY DISEASES, in which 1,25-DIHYDROXYVITAMIN D3 synthesis by the kidneys is impaired, leading to reduced negative feedback on PARATHYROID HORMONE. The resulting SECONDARY HYPERPARATHYROIDISM eventually leads to bone disorders.
Concepts Disease or Syndrome (T047)
MSH D012080
ICD9 588.0
ICD10 N25.0
SnomedCT 197668007, 16726004, 155858005, 266617009
English Osteodystrophies, Renal, Renal Osteodystrophies, OSTEODYSTROPHY, PANNEPHRITIC, OSTEODYSTROPHY, RENAL, Renal osteodystrophy NOS, renal osteodystrophy, renal osteodystrophy (diagnosis), OSTEODYSTROPHY RENAL, Renal osteodystrophy NOS (disorder), Renal Osteodystrophy [Disease/Finding], osteodystrophy renal, renal bone disease, renal disease bone, Renal osteodystrophy, ROD - Renal osteodystrophy, Renal bone disease, Renal osteodystrophy (disorder), osteodystrophy; renal, renal; osteodystrophy, Renal Osteodystrophy, Osteodystrophy, Renal
Swedish Renal osteodystrofi
Japanese ジンセイコツイエイヨウショウ, 腎性くる病, 線維性骨炎, 腎性骨異栄養症, 腎性骨ジストロフィー, 骨異栄養症-腎性, 腎性骨形成異常症, 腎性骨症, 骨炎-線維性, 腎性骨形成異常, 腎性骨ジストロフィ, くる病-腎性, 骨ジストロフィー-腎性
Czech renální osteopatie, renální osteodystrofie, Renální osteodystrofie
Spanish Renal osteodystrophy, osteodistrofia renal (trastorno), osteodistrofia renal, SAI (trastorno), osteodistrofia renal, SAI, osteodistrofia renal, Osteodistrofia renal, Osteodistrofia Renal
Finnish Renaalinen osteodystrofia
Korean 콩팥(신장성) 뼈형성장애
Polish Osteodystrofia nerkowa, Krzywica nerkowa
Hungarian Renalis osteodystrophia
Dutch osteodystrofie; renaal, renaal; osteodystrofie, renale osteodystrofie, Dystrofie, renale osteo-, Osteodystrofie, renale, Renale osteodystrofie
Portuguese Osteodistrofia renal, Osteodistrofia Renal
German renale Osteodystrophie, Renale Osteodystrophie
French Ostéodystrophie rénale
Italian Osteodistrofia renale