HYPEREMIA & CONGESTION II

HYPEREMIA AND CONGESTION: There are 3 main basic requirements for normal circulatory function:- Normal anatomic features Normal physiologic controls, and Normal 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 congestion Haemorrhage and shock Circulatory 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 legs Vericosities Pressure by pregnant uterus Tumours, 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 as Pulmonary fibrosis Emphysema

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 heavy Lungs are firm in consistency The 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 tissue Minute intra-alveolar haemorrhages due to - rupture of dilated and congested capillaries haemosiderin pigment due to; - breakdown of erythrocytes Heart 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 enlarged C/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 hypoxia Central veins and sinusoids – distended and filled with blood Centrilobular 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 or Portal hypertension – due to cirrhosis of the liver Grossly:- Enlarged spleen The organ is deeply congested and cynotic

CVC SPLEEN CONT-- Microscopically: Red pulp: Congestion Marked sinusoidal dilatation Areas of recent and old haemorrhage Organized 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 KIDNEY Grossly: Slightly enlarged kidneys The medulla is congested Microscopically: Degenerative changes of tubules: - cloudy swelling - fatty change The glomeruli: - mesangial proliferation