Introduction
Rheological disorders are disturbances of blood flow in the microcirculation. This topic covers prestasis, stasis and the sludge phenomenon, their causes and outcomes, leukostasis, and the links of the microcirculation.
Stasis
- Stasis is a stoppage of blood flow in the vessels of the microcirculatory system (capillaries).
- Capillaries and veins are paralytically dilated and filled with blood (both have lost the ability to contract and dilate from excessive filling with blood).
- Homogenous eosinophilic masses are seen in the lumen.
- Short-term stasis is reversible. Prolonged stasis leads to hyaline thrombi, increased vascular permeability, edema and bleeding.
Prestasis
Prestasis: columns of erythrocytes are stuck together.
Sludge syndrome
The sludge phenomenon is regarded as a type of stasis, characterised by sticking of erythrocytes, leucocytes and thrombocytes to each other, accompanied by changes in blood viscosity (blood viscosity increases).
Causes of stasis
- physical factors (temperature increase or decrease)
- chemical factors
- infection
- infectious-allergic factors
- autoimmune factors
Stasis can also be discirculatory, due to venous hyperemia or ischemia.