Page 121 - Textbook of Pathology, 6th Edition

DISTURBANCES IN THE VOLUME OF Passive Hyperaemia (Venous Congestion) 105
CIRCULATING BLOOD
The dilatation of veins and capillaries due to impaired venous
HYPERAEMIA AND CONGESTION drainage results in passive hyperaemia or venous congestion,
Hyperaemia and congestion are the terms used for localised commonly referred to as congestion. Congestion may be acute
increase in the volume of blood within dilated vessels of an or chronic, the latter being more common and called chronic
organ or tissue; the increased volume from arterial and venous congestion (CVC). The affected tissue or organ is bluish CHAPTER 5
arteriolar dilatation being referred to as hyperaemia or active in colour due to accumulation of venous blood (cyanosis).
hyperaemia, whereas the impaired venous drainage is called Obstruction to the venous outflow may be local or systemic.
venous congestion or passive hyperaemia. If the condition Accordingly, venous congestion is of 2 types:
develops rapidly it is called acute, while more prolonged and Local venous congestion results from obstruction to the
gradual response is known as chronic. venous outflow from an organ or part of the body e.g. portal
Active Hyperaemia venous obstruction in cirrhosis of the liver, outside pressure
The dilatation of arteries, arterioles and capillaries is effected on the vessel wall as occurs in tight bandage, plasters,
tumours, pregnancy, hernia etc, or intraluminal occlusion
either through sympathetic neurogenic mechanism or via the by thrombosis.
release of vasoactive substances. The affected tissue or organ
is pink or red in appearance (erythema). Systemic (General) venous congestion is engorgement of
The examples of active hyperaemia are seen in the systemic veins e.g. in left-sided and right-sided heart failure
following conditions: and diseases of the lungs which interfere with pulmonary
Inflammation e.g. congested vessels in the walls of alveoli blood flow like pulmonary fibrosis, emphysema etc. Usually
in pneumonia the fluid accumulates upstream to the specific chamber of
Blushing i.e. flushing of the skin of face in response to the heart which is initially affected (Chapter 16). For
emotions example, in left-sided heart failure (such as due to mechanical
Menopausal flush overload in aortic stenosis, or due to weakened left Derangements of Homeostasis and Haemodynamics
Muscular exercise ventricular wall as in myocardial infarction) pulmonary
High grade fever congestion results, whereas in right-sided heart failure (such
Goitre as due to pulmonary stenosis or pulmonary hypertension)
Arteriovenous malformations systemic venous congestion results. Fig. 5.9 illustrates the
Clinically, hyperaemia is characterised by redness and mechanisms involved in passive or venous congestion of
raised temperature in the affected part. different organs.

Figure 5.9 Schematic representation of mechanisms involved in chronic venous congestion (CVC) of different organs.