Hemodynamic disorders
Hyperaemia and congestion
Increased blood volume in a tissue
Hyperemia Congestion
Active vasodilatation of arterioles & capillaries resulting in increased blood flow in a tissue Passive dilatation of veins , venules & capillaries due to venous outflow obstruction
The affected tissues appear red → due to engorgement with oxygenated blood The affected tissues appear blue-red (cyanosed) → due to engorgement with deoxygenated blood
1-Local Acute Sudden occlusion of vein by Thrombus
Types of venous Chronic Gradual incomplete occlusion of vein e.g
Congestion congestion ► Pregnancy: uterine enlargement → compression of iliac veins → congestion of leg veins.
► Mitral stenosis or left sided heart failure →congestion of pulmonary veins.
2-Systemic Acute Chronic
(generalized) Definition Rapid generalized congestion of organs Gradual congestion of the systemic veins (venae cava) and their tributaries with or without congestion of pulmonary veins
venous Aetiology Acute heart failure a- Left sided heart failure → right ventricular failure b- Right sided heart failure
congestion
Effects of Acute congestion Chronic congestion
congestion Affected organ ● Edema due to increased capillary hydrostatic pressure ● Focal hemorrhage due to rupture of capillaries
- Blue red - Edematous ● Thrombosis due to stasis ● Varicosity: dilatation, elongation and tortuosity of the chronically congested veins
- Hemorrhagic ● Parenchymal cell atrophy ● Organs appear brown (hemosiderin) & contracted
Infarction
Definition An infarct is an area of ischemic necrosis caused by sudden occlusion of the vascular supply to the affected tissue.
Aetiology 1- Arterial occlusion by thrombus or embolus :99% of cases 2- Extensive venous occlusion: Less common causes
Types of Pale occur with Arterial occlusion in solid organs with end arteries e.g heart & kidney and spleen
infarct Red occur in:
hemorrhagic ► Venous occlusions :
● with arterial occlusion as in strangulated hernia (intestine) & Ovarian or testicular torsion
● without arterial occlusion as Brain infarction due to jugular vein thrombosis
► In loose tissues as lung & small intestine. Blood can collect in infarcted zone.
► Tissues with a dual circulation e.g lung and small intestine permitting blood flow from the patent vessels into infarcted area
(such perfusion not sufficient to rescue the ischemic tissues).
General Gross features ► Pyramidal or wedge shaped infarct with
pathological ● its apex at the site of vascular occlusion ● its base at surface of the organ due to the fan shaped distribution of end arteries
features of ► When the infarct base is a serosal surface; pleura, pericardium, peritoneum →it shows fibrinous inflammation
infarcts ► Margins of the infarct are hyperemic due to inflammation ► Early, the infarct is swollen but later, it becomes contracted due to healing
► Infarcts may be pale or hemorrhagic
Microscopic features ● Infarcts of all organs → ischemic coagulative necrosis EXCEPT CNS → liquifactive necrosis
● The margins of the infarct show dilated capillaries & some inflammatory cells.
Hyperaemia and congestion
Increased blood volume in a tissue
Hyperemia Congestion
Active vasodilatation of arterioles & capillaries resulting in increased blood flow in a tissue Passive dilatation of veins , venules & capillaries due to venous outflow obstruction
The affected tissues appear red → due to engorgement with oxygenated blood The affected tissues appear blue-red (cyanosed) → due to engorgement with deoxygenated blood
1-Local Acute Sudden occlusion of vein by Thrombus
Types of venous Chronic Gradual incomplete occlusion of vein e.g
Congestion congestion ► Pregnancy: uterine enlargement → compression of iliac veins → congestion of leg veins.
► Mitral stenosis or left sided heart failure →congestion of pulmonary veins.
2-Systemic Acute Chronic
(generalized) Definition Rapid generalized congestion of organs Gradual congestion of the systemic veins (venae cava) and their tributaries with or without congestion of pulmonary veins
venous Aetiology Acute heart failure a- Left sided heart failure → right ventricular failure b- Right sided heart failure
congestion
Effects of Acute congestion Chronic congestion
congestion Affected organ ● Edema due to increased capillary hydrostatic pressure ● Focal hemorrhage due to rupture of capillaries
- Blue red - Edematous ● Thrombosis due to stasis ● Varicosity: dilatation, elongation and tortuosity of the chronically congested veins
- Hemorrhagic ● Parenchymal cell atrophy ● Organs appear brown (hemosiderin) & contracted
Infarction
Definition An infarct is an area of ischemic necrosis caused by sudden occlusion of the vascular supply to the affected tissue.
Aetiology 1- Arterial occlusion by thrombus or embolus :99% of cases 2- Extensive venous occlusion: Less common causes
Types of Pale occur with Arterial occlusion in solid organs with end arteries e.g heart & kidney and spleen
infarct Red occur in:
hemorrhagic ► Venous occlusions :
● with arterial occlusion as in strangulated hernia (intestine) & Ovarian or testicular torsion
● without arterial occlusion as Brain infarction due to jugular vein thrombosis
► In loose tissues as lung & small intestine. Blood can collect in infarcted zone.
► Tissues with a dual circulation e.g lung and small intestine permitting blood flow from the patent vessels into infarcted area
(such perfusion not sufficient to rescue the ischemic tissues).
General Gross features ► Pyramidal or wedge shaped infarct with
pathological ● its apex at the site of vascular occlusion ● its base at surface of the organ due to the fan shaped distribution of end arteries
features of ► When the infarct base is a serosal surface; pleura, pericardium, peritoneum →it shows fibrinous inflammation
infarcts ► Margins of the infarct are hyperemic due to inflammation ► Early, the infarct is swollen but later, it becomes contracted due to healing
► Infarcts may be pale or hemorrhagic
Microscopic features ● Infarcts of all organs → ischemic coagulative necrosis EXCEPT CNS → liquifactive necrosis
● The margins of the infarct show dilated capillaries & some inflammatory cells.
