高黏滯度與白血球滯留

Buzzwords → Dx

Diagnostic Criteria

• Hyperviscosity: clinical triad + serum viscosity ≥4 cP (normal 1.4–1.8); typically IgM >4 g/dL but threshold variable (some patients symptomatic at lower levels).
• Leukostasis: clinical (neuro / pulmonary symptoms) + WBC >50–100K (AML) or much higher in ALL with mediastinal mass; CNS / pulmonary CT findings.

Workup

• Hyperviscosity:
  • Serum viscosity, IgM/IgG/IgA quantitation, SPE/IFE.
  • Fundoscopy (sausage-link veins).
  • Cryoglobulin testing.
  • vWF panel (acquired vWD in WM).
• Leukostasis:
  • CBC + manual differential + blast %.
  • Smear (immature WBC predominance).
  • CXR + ABG (don't trust pulse ox).
  • LDH, uric acid, K, Ph, Ca (TLS).
  • Coagulation panel (DIC in APL).
  • Marrow + cytogenetics (don't delay induction for full workup).

Treatment Algorithm

flowchart TD
  A[Suspected hyperviscosity / leukostasis] --> B{Type}
  B -- hyperviscosity (IgM, MM, etc.) --> C[Plasmapheresis IMMEDIATELY<br>1-1.5 plasma volume<br>removes IgM mechanically]
  C --> D[Treat underlying disease<br>BTKi for WM, regimens for MM]
  B -- leukostasis high WBC AML/ALL --> E{Hemodynamic / neuro / pulm distress?}
  E -- yes severe --> F[Cytoreduction:<br>hydroxyurea + IVF + leukapheresis<br>+ start induction chemo ASAP]
  E -- mild --> G[Hydroxyurea + induction chemo<br>often no leukapheresis needed]
  F --> H[NO RBC transfusion before WBC reduced<br>increases viscosity]
  G --> H
  F --> I[TLS prophylaxis<br>rasburicase + IVF]
  G --> I
  H --> J{APL suspected? faggot cells / DIC?}
  J -- yes --> K[Start ATRA on suspicion<br>aggressive coagulopathy mgmt]
  J -- no --> L[Continue induction chemotherapy]

Pearls / Pitfalls

• Plasmapheresis FIRST in hyperviscosity — don't transfuse RBCs first as RBCs add viscosity. Plasmapheresis removes IgM mechanically (effective within hours).
• DON'T transfuse RBCs in leukostasis before reducing WBC — increases viscosity. Stabilize WBC with hydroxyurea + leukapheresis first; then transfuse if Hb critically low.
• Hyperleukocytosis spurious labs: pseudo-↑platelet count (WBC fragments), pseudo-hypoxemia (WBC O₂ consumption in tube), pseudo-hyperkalemia, pseudo-↓glucose (WBC glucose consumption). Always confirm before treating.
• APL with hyperleukocytosis = differentiation syndrome risk during ATRA induction — pre-treat with hydroxyurea + dexamethasone prophylaxis when WBC >10K.
• Leukapheresis is bridge to chemo, not replacement. Some studies suggest no survival benefit; consensus is to use in symptomatic leukostasis only, while always starting induction chemo concurrently.
• CNS leukostasis can mimic stroke or seizure — neurology + emergent neuroimaging.
• Cryoglobulinemia + WM → avoid cold; warm IV fluids + transfusions; don't use refrigerated blood products.
• Acquired vWD in WM contributes to bleeding diathesis — separate from hyperviscosity but related.
• Type II vWD in extreme thrombocytosis (PV, ET) → similar bleeding from acquired vWD; cytoreduce platelets.
• Pediatric ALL T-cell with mediastinal mass + leukostasis — emergent pediatric oncology consultation; airway compromise risk.
• Hyperviscosity from polycythemia (PV, secondary erythrocytosis) → therapeutic phlebotomy first-line.

Cross-references

• Waldenström — IgM hyperviscosity
• MM — IgG/A hyperviscosity
• AML — leukostasis at induction
• APL — DIC + DS + hyperleukocytosis
• ALL — high-WBC leukostasis
• TLS — concurrent risk
• Apheresis — TPE / leukapheresis

相關題目

• Q-178 — Hyperviscosity — IgM threshold and clinical features
• Q-179 — Hyperleukocytosis spurious labs
• Q-180 — APL with hyperleukocytosis — DS prophylaxis

Sources