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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