Nephrology Grand Rounds

1
Nephrology Grand Rounds

• 5/13/08

2
(No Transcript)
3
Refractory Hyperparathyroidism

• Brad Weaver

4
Causes of refractory HPTH

• Inadequate therapy
• Persistent hyperphosphatemia
• Acquired abnormalities of parathyroid gland
• Polyclonal cell proliferation (diffuse
  hyperplasia) summative effect of each cell
  having a nonsuppressible basal secretion of PTH
• Monoclonal cell proliferation can lead to
  adenomatous cells that do not respond to
  appropriate feedback

5
General indications for parathyroidectomy

• Symptomatic patients with elevated and
  nonsuppressible iPTH (usually gt800)
• Hyperparathyroid bone disease diagnosed by
  radiographical evidence or bone biopsy
• Extensive extraskeletal calcifications or
  calciphylaxis
• Refractory pruritis
• Unexplained myopathy
• Severe hypercalcemia (mainly seen in primary HPTH)

6
Effects of parathyroidectomy
7
Effects cont.

• Parathyroidectomy may have beneficial effects on
  humoral immunity
• Prospective study 1999 34 dialysis patients
  received parathyroidectomy for 2HPTH.
• At 12 months there were significant increases in
  serum levels of IgG, IgM, IgA, C3, C4, and CH50
• Nutrional status also improved as measured by
  significant increases in albumin and hematocrit

Am J Surg 1999 Oct178(4)332-6.
8
VA Study 2004 U. of Washington

• Observational matched cohort study of 4558
  dialysis patients undergoing parathyroidectomy
  vs. 4558 matched controls
• Higher 30 day mortality in parathyroidectomy
  group 3.1 vs. 1.2 in controls
• Long term survival better in parathyroidectomy
  group 53 vs. 47 months
• Survival curves crossed at 587 days s/p surgery

Kidney Int 2004 Nov66(5)2010-6
9
Parathyroidectomy and transplant

• What to do with a patient with refractory
  hyperparathyroidism on transplant list?
• Most cases (approximately 96) of HPT resolve
  after transplant
• HPT that does not resolve may cause increased
  risk to the renal graft and may cause
  hypertension
• However, parathyroidectomy in transplant patients
  carries a small risk of sudden deterioration of
  renal graft function

10
Surgical considerations

• In primary HPTH, nuclear medicine scans
  (technetium-99m-sestamibi or I-123 SPECT) are
  used to detect location of glands prior to
  surgery
• Unknown if useful in 2HPT due to renal failure
• Total parathyroidectomy with autotransplantation
  is the most common technique
• Reoperation rates for persistent HPT are 6-14

11
Hungry bone syndrome

• Severe hypocalcemia following parathyroidectomy
  in spite of normal or elevated PTH levels
• Sudden decrease in PTH disrupts bone equilibrium
  of resorption vs. formation
• Most common in patients with severe preexisting
  bone disease
• Occurred in 20 of 148 dialysis patients
  undergoing parathyroidectomy in one series

Kidney Int Suppl 2003 Jun(85)S97-100
12
Hungry bone syndrome cont.

• Hypocalcemia
• Nadirs 2-4 days post op
• If tetany and seizures occur, they can increase
  fracture risk
• Sudden heart failure has been attributed to
  hypocalcemia
• Hypophosphatemia and hypomagnesemia
• Mainly seen in primary HPTH
• Hyperkalemia
• Occurs in 80 of dialysis patients post-op

13
Treatment

• Oral calcium 2 to 4 g per day
• IV calcium for symptomatic hypocalcemia or Ca lt
  7.5 1 amp of calcium gluconate instilled over
  10 to 20 minutes followed by maintenance drip
• Vitamin D supplementation calcitriol
• Hemodialysis use high calcium bath (3.5 mEq/L
  Ca)
• Peritoneal dialysis add 1 to 3 amps of calcium
  gluconate to each bag of dialysate