Both Cin & Etlc classes lower PTH levels but have disparate effects on Ca+ & PO4 levels; thus, we choose different ttt approaches based on SPO4 & Ca+
Parathyroid adenoma
List of abbreviations:
1) Calt: Calcitriol
2)
Cin: Cinacalcet.
3)
Etlc: Etelcalcetide.
4)
Cmm: Calcimimetics
5)
PTH: Parathyroid hormone
6) Hpr: hyperparathyroidism
TREATMENT APROACH OF
HYPERPARATHYROIDISM
Both Cin & Etlc classes lower PTH levels
but have disparate effects on Ca+ & PO4 levels; thus, we choose different ttt
approaches based on SPO4 & Ca+ levels. The optimal approach for management of
hyperparathyroidism is greatly consistent with the 2017
KDIGO guidelines
as follows:
1) Ptns
with phosphate <5.5 mg/dL (<1.78 mmol/L) & Ca+
<9.5 mg/dL (<2.37 mmol/L) can be ttt with Calt monotherapy. However, other vit D analogs are also efficacious in PTH reduction.
2) Some
physicians suggest such ptns ttt with Cmm
rather than Calt or a synthetic vit D
analog, despite of lacking evidence of any survival benefits for Cmm.
3) Cin should NOT be used if Ca+
level is <8.4 mg/dL (<2.1 mmol/L),
since it induces hypo- Ca+. Such ptns could
be ttt with Calt.
4) Dose
plan is empirical, with the target of
higher doses of Calt or synthetic vit
D analogs to reach a target plasma PTH
level & maintain S PO4≤5.5 mg/dL.
5) Concurrent
means to maintain goal S.PO4 are applied.
6) Ptns
with inadequate decline of PTH
on Calt, we can add Cin, providing the ca is >8.4 mg/dL. Almost
50% of ptns with
severe Hpr may exhibit little or No lowering in pl PTH with Calt therapy.
7) The
addition of Cin may augment the
chance to achieve PTH target value
and permit lowering the doses of vit D
analog, that is less likely to induce hyper-Ca+
or hyper-PO4.
8) Cin can be initiated at 30 mg/d. orally, with stepwise
increments to 60, 90, & 180 mg/d. Dose changes can be proceeded every 4 wk until target
is achieved.
9) Ptns
with s PO4 ≥ 5.5 mg/dL (≥1.78 mmol/L) or S.Ca+ ≥9.5
mg/dL (≥2.37 mmol/L) &
persistently high PTH, despite
maximal efforts to decline PO4, initiate
Cmm rather than Calt or a synthetic vit D analog.
10) Calcitriol & synthetic vit D analogs should NOT be used in such ptns at least initially, as they
both elevate S.Ca+ & PO4.
11) Cin should not be initiated if S Ca+
is <8.4 mg/dL (<2.1 mmol/L), as it
induces Ca+ decline.
12) Maintain
s levels of corrected total Ca+ between 8.4 & 9.5 mg/dL (2.10-2.37 mmol/L).
13) Ptns
who do Not have enough PTH reduction with Cin
alone, we can add Calt or a synthetic
vit D analog, providing the phosphate <5.5 mg/dL (<1.78 mmol/L) & Ca+ <9.5 mg/dL (<2.37 mmol/L).
14) Etelcalcetide (Etlc): Etlc
was superior to Cin in decreasing PTH by > 30 %. Nausea & vomiting
were comparable. However, hypocalcemia was more evident in Etlc
g requiring increasing S.Ca+ via:
1. Increasing
dialysate
Ca.
2. Giving
Ca-containing PO4 binders,
3. Oral
Ca+ supplements, Calt
and active vit D).
-Etlc
therapy > may prolong QT interval in many ptns. However, as it’s provided IV,
its compliance is not certain.
COMMENTS