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HYPEREMIA & CONGESTION II
HYPEREMIA AND CONGESTION:
There are 3 main basic requirements for normal circulatory function:-
Normal anatomic featuresNormal physiologic controls, andNormal biochemical composition of the blood.NB: These are essential to maintain normal
blood flow and perfusion of tissues
Hyperemia and congestion cont--
• Derangements of blood flow or haemodynamic disturbances are considered under 2 broad headings:-
Disturbances in the volume of the circulating blood. These include:
Hyperemia and congestionHaemorrhage and shockCirculatory disturbances of obstructive nature: thrombosis, embolism, ischaemia and infarction
DISTURBANCES IN THE VOLUME OF CIRCULATING BLOOD:
Hyperemia and congestion:Are the terms used for increased volume of
blood within dilated vessels of an organ or tissue.
Hyperemia (Active hyperemia):-Is the increased volume from arterial and
arteriolar dilatation Venous congestion (Passive hyperemia):Is the impaired venous drainage
ACTIVE HYPEREMIA• The dilatation of arteries, arterioles and capilaries is effected
through; Sympathetic neurogenic mechanism or Via the release of vasoactive substances• The affected tissue or organ is pink or red in appearance
(erythema).• Examples of active hyperemia are:- Inflammation e.g. in pneumonia Muscular exercise High grade fever Blushing i.e. flushing in the skin of face in response to emotions.
HYPEREMIA & CONGESTION• The dilatation of veins and capillaries due to
impaired venous drainage results in passive hyperemia or venous congestion, commonly referred to as congestion
• Congestion may be of 2 types:Acute congestion or Chronic congestion – this being more common and
is called Chronic Venous Congestion(CVC)• In CVC the affected tissue or organ is bluish in colour
due to accumulation of venous blood (Cynosis)
Examples of disorders cont---• Passive congestion:-Mechanical obstruction due to thrombosis of veins of
lower legsVericositiesPressure by pregnant uterusTumours, etc • Postural oedema:-Transient oedema of feet and ankles due to increased
venous pressure seen in individuals who remain standing erect for a long time e.g.traffic constables
CVC cont----
• Obstruction to the venous outflow may be local or systemic
• Accordingly, venous congestion may be of 2 types:
Local venous congestion:Results from obstruction to the venous
outflow from an organ or part of the body- e.g. portal venous obstruction in cirrhosis of
the liver, pregnancy, hernia, thrombosis
CVC cont--
Systemic venous congestion:Is engorgement of systemic veins, e.g. - left-sided and right-sided heart failure - diseases of the lungs which interfere
pulmonary blood flow, such asPulmonary fibrosisEmphysema
MORPHOLOGY OF CVC OF ORGANS
• Morphologic changes is seen most commonly in the lungs, liver, spleen and kidney
CVC LUNG:CVC of lung occurs in left heart failure, so that
there is consequent rise in pulmonary venous pressure.
Morphology of lung cont--- Grossly:The lungs are heavyLungs are firm in consistencyThe sectioned surface of the lung is; - dark brown in colour, referred to as brown induration of
the lung due to the haemosiderin pigmentation and fibrosis
Histologically:The alveolar septa are widened due to; - interstitial oedema and - dilated and congested capillaries
Morphology of lung histologically cont---
The septa are midly thickened due to; - slight increase in fibrous connective tissueMinute intra-alveolar haemorrhages due to - rupture of dilated and congested capillaries haemosiderin pigment due to; - breakdown of erythrocytesHeart failure cells – are alveolar macrophages
which has taken up haemosiderin pigment
Lung-in heart failure (hemosiderin pigment, congestion)
Lung: CVC perl’s prussian blue for iron (Fe+)
Heart failure cells -lung
Heart failure cells - lung
MORHOLOGY cont---CVC LIVER:• Occurs in RHF or• Occlusion of inferior vena cava and hepatic vein Grossly:The liver is enlargedC/S – nutmeg appearance of liver due to:- - red and yellow mottled appearance corresponding
to ( congested centre of lobules and fatty peripheral zone respectively)
NUTMEG LIVER
NUTMEG LIVER
NUTMEG LIVER
CVC Liver cont--
Microscopically:More marked congestion in centrilobular
zone – due to severe hypoxiaCentral veins and sinusoids – distended and
filled with bloodCentrilobular hepatocytes-haemorrhagic
necrosis due to degenerative changes
CVC Liver cont--
Long standing cases:- - fine centrilobular fibrosis - regeneration of hepatocytes – resulting in
cardiac sclerosis (cirrhosis) - fatty change of hepatocytes – in peripheral
zone of the lobule because this zone is less severely affected by chronic hypoxia
CVC: LIVER-nutmeg around central vein from (RHF)
LIVER: pronounced CVC(light yellow pigment”lipochrome” in necrotic hepatocytes) around central vein
LIVER:longstanding CVC (cardiac sclerosis “cirrhosis”)
CVC SPLEEN:
• Occurs in the following situations;Right-sided heart failure orPortal hypertension – due to cirrhosis of the
liverGrossly:-• Enlarged spleen• The organ is deeply congested and cynotic
CVC SPLEEN CONT--Microscopically:• Red pulp:CongestionMarked sinusoidal dilatationAreas of recent and old haemorrhageOrganized areas of haemorrhage – called
Gamna gandy bodies or siderofibrotic nodules ( = are deposits of haemosiderin pigment and calcium salts) on fibrous connective tissue.
CVC spleen-microcopically cont--
Late stages: - hyperplasia of microphages - hyperplasia of fibroblasts - hyperplasia of red pulp
MORPHOLOGY OF THE KIDNEYGrossly:Slightly enlarged kidneysThe medulla is congestedMicroscopically:Degenerative changes of tubules: - cloudy swelling - fatty changeThe glomeruli: - mesangial proliferation