ISCHEMIC STROKE / ETIOLOGY

Hyperviscosity syndrome

Created 21/03/2022, last revision 02/04/2022

  • hyperviscosity syndrome (HVS) is a clinical-laboratory syndrome resulting from increased blood viscosity
  • most cases are associated with excessive immunoglobulin levels  – non-corpuscular hyperviscosity
  • less frequently, HVS occurs as a result of increased blood elements, e.g., in myeloproliferative diseases – corpuscular hyperviscosity
  • prompt treatment is needed to avoid progression to multisystem organ failure

Pathophysiology

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Etiology

Corpuscular HVS
  • increased blood viscosity is caused by the multiplication of blood elements (myeloproliferative diseases), sometimes platelet hyperaggregability is involved
    • most commonly in polycythemia vera (PV)  Thrombus in CCA/ICA junction in a patient with polycythemia vera    [Griesshammer, 2021]
    • the blastic phase of chronic myeloid leukemia
    • hyperleukocytosis in acute myeloid leukemia
    • leukostasis syndrome (microcirculation disorder resulting from the accumulation of leukocytes that are overrepresented in the peripheral blood; especially in chronic myeloid leukemia)
Noncorpuscular HVS
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Clinical presentation

Clinical symptoms are caused by hypoperfusion and reduced tissue oxygenation due to stasis of hyperviscous blood or thrombosis in the venous/arterial circulation (typically in polycythemia vera). The manifestations of HVS and the viscosity values do not correlate. The manifestations of HVS occur when the individual viscosity threshold is exceeded (it ranges from 2-12 times the normal plasma/serum viscosity)

  • neurological symptoms
    • encephalopathy – confusion, headache, disturbance of consciousness, including coma (“paraproteinemic coma”)
    • epileptic seizures
    • TIA/ischemic stroke
    • amaurosis fugax
  • exacerbation of underlying diseases
    • cardiac – angina pectoris, congestive heart failure, tachycardia
    • respiratory – exacerbation of chronic lung diseases with dyspnoea, pulmonary edema
    • renal – worsening of CKD, acute renal failure (often due to acute tubular necrosis)
  • peripheral ischemia (acrocyanosis, livedo reticularis, limb pain)
  • hemorrhagic manifestations (especially mucosal and cutaneous petechiae) due to the interaction with platelets and pathological binding of coagulation factors with immunoglobulin molecules)
  • general symptoms
    • low-grade fever
    • non-specific manifestations of a generalized malignancy (anorexia, night sweats, weight loss)

Diagnostic evaluation

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Therapy

  • the basis is the treatment of an underlying hematological disease
  • plasma exchange is indicated in non-corpuscular HVS
    • elevated serum viscosity alone is not an indication for PE – careful evaluation of the clinical manifestations of hyperviscosity syndrome is required (do not delay PE if present)
    • exceptionally, PE can be performed as a stand-alone palliative procedure in the context of symptomatic therapy of malignant disease
  • corpuscular HVS can be managed by therapeutic leukapheresis, erythrocytapheresis, or thrombocyte apheresis
  • adequate hydration
  • treatment of hypercalcemia (occurs in up to 30% of patients with malignancy and often worsens HSV symptoms)
  • correction of possible anemia and/or thrombocytopenia
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