John Stuart

Summary. Coagulation activity and whole-blood viscosity were measured in the steady state, and serially during painful crisis, in eight patients with sickle-cell anaemia. Platelet and coagulation activation occurred in the steady state and became more pronounced early in crisis. Whole-blood viscosity increased during crisis in parallel with plasma fibrinogen.Similar changes were found in a parallel study of 20 patients with localized bacterial or viral infection who did not have sickle-cell anaemia. Reports of platelet activation, hypercoagulability, and hyperviscosity during painful crisis therefore reflect secondary changes arising from vascular stasis, precipitating infection, and an acute-phase protein reaction. Although secondary, these changes may contribute to vascular occlusion by an additive effect in vessels already partially occluded by sickled cells.

Forty patients with atherosclerotic peripheral vascular disease, as compared to 29 healthy controls, showed a significant increase in platelet number and activity, a neutrophil leucocytosis, and a raised level of several acute-phase reactant proteins (fibrinogen, antithrombin III, factor VIII, and serum globulin). The hyperproteinaemia was associated with increases in plasma-, serum-, and blood-viscosity and is the likely cause of the hyperviscosity of vascular disease. These multiple haemostatic abnormalities closely resemble the non-specific, haematological stress-syndrome response to acute and chronic inflammatory disorders. In atherosclerosis also they may represent a non-specific, secondary response and neither be of aetiological significance nor reflect continuing low-grade intravascular coagulation.

HEM Kay, PJ Knapton, JP O'Sullivan, et al. ... Therapy Associated with Methotrexate Encephalopathy in Acute Leukaemia ... References http://adc.bmj.com/content/47/253/344#related-urls Article cited in: ... HEM KAY, PJ KNAPTON, JP O'SULLIVAN, DG WELLS, RUTH F. HARRIS, ...