排鐵治療

Buzzwords → Dx

Diagnostic / Decision Concepts

• Iron overload develops with cumulative RBC transfusions — each unit = ~200 mg iron.
• Ferritin >1000 ng/mL (often >2500) = chelation threshold.
• MRI T2* (cardiac) and LIC MRI (hepatic) for body iron burden.
• Cardiac iron is leading mortality in transfusion-dependent thalassemia.

Workup before initiation

• Ferritin trend.
• Cumulative transfusion units.
• Liver function tests, Cr/eGFR, urinalysis.
• MRI T2* cardiac + LIC (annually in chronic transfusion).
• Endocrine workup (TSH, glucose, gonadal axis, calcium) if long-term.
• Audiometry + ophthalmology (DFO baseline).
• CBC for deferiprone (weekly–biweekly for agranulocytosis).

Treatment Algorithm

flowchart TD
  A[Transfusion-dependent; cumulative iron loading] --> B[Ferritin >1000-2500 OR ≥20 RBC units]
  B --> C{Disease + organ priority}
  C -- β-thal major / SCD / MDS<br>cardiac iron concern --> D[Deferiprone or DFO + deferiprone combo for cardiac]
  C -- routine first-line --> E[Deferasirox PO daily]
  C -- compliance issues with PO --> F[Deferoxamine SC overnight]
  D --> G[Monitor q1-2 wk CBC for agranulocytosis (deferiprone)]
  E --> H[Monitor Cr, LFTs, urinalysis q month for first 3 mo, then q3 mo]
  F --> I[Monitor audiometry + ophthalmology annually]
  G --> J[Adjust dose by ferritin trend; goal <500 ng/mL or LIC <7]
  H --> J
  I --> J
  J --> K[Treat endocrinopathies + cardiac function annually]

Pearls / Pitfalls

• Deferiprone has cardiac iron preference (lipophilic, crosses cell membranes) — preferred in cardiac iron overload, often combined with DFO.
• Deferasirox renal toxicity — monitor Cr monthly (esp. early); proteinuria; doses adjusted in CKD. Avoid in CrCl <40.
• Deferiprone agranulocytosis ~1 % — weekly CBC initially; stop immediately if ANC <500.
• DFO ototoxicity + retinopathy — annual audiometry + ophth exam.
• Combination DFO + deferiprone for severe cardiac iron — synergistic; "shuttle hypothesis".
• Vitamin C in moderate doses can help iron mobilization with DFO; avoid high-dose vit C with thalassemia (may worsen iron toxicity).
• Pediatric thalassemia chelation start age 2–5 (after baseline iron loading) — DFO traditional; deferasirox now common.
• Pregnancy + iron chelation — DFO safer (limited data); deferasirox/deferiprone teratogenic.
• MDS chelation in lower-risk transfusion-dependent: TELESTO trial (deferasirox) showed PFS benefit; routine but not universally adopted.
• SCD chelation less aggressive (less iron loading) — start when ferritin >1000 + cumulative >20 RBC units; DFO traditional; deferasirox common.
• Ferritin can mislead — acute phase reactant; correlate with LIC + MRI.
• Iron chelation may also reduce some SCD-specific complications (NTDT and thalassemia data extrapolated).

Cross-references

• β-thalassemia — chelation lifelong
• SCD — chronic transfusion + chelation
• MDS — chelation in lower-risk transfusion-dependent
• Post-HCT iron overload
• Sideroblastic anemia chelation
• Drug Regimens — chelators

相關題目

• Q-208 — Iron chelation indications
• Q-209 — Iron chelation — cardiac iron preference
• Q-210 — Iron chelation in lower-risk MDS (TELESTO)

Sources