Page 85 - Concise Pathology for Exam Preparation ( PDFDrive )

70 SECTION I General Pathology

Hypoperfusion

Renal ischaemia ↑ ADH
Baroreceptors (posterior pituitary)
(in carotid sinus and
+
↓ Na in renal tubules aortic arch) activated
↑ Retention of H O
2
Activation of Vasomotor centre affected
renin­­angiotensin
­­aldosterone axis
↑ Sympathetic outflow

Renal ischaemia

↓ GFR

↓ Excretion of Na +

↑ Renal retention of Na + and H O

2
FLOWCHART 4.1. Normal regulatory mechanisms responsible for maintaining sodium and
water balance.
Q. Write briefly on the pathogenesis of oedema.
Ans. Pathogenesis oedema shown Flowchart 4.2.
is
of
in

• Nutritional deficiency
• ↓ Hepatic synthesis
• Nephritic/nephrotic syndrome
Hypoalbuminaemia
↓ Plasma oncotic pressure
Heart failure
(cardiac oedema)

↑ Central venous pressure ↓ Cardiac output ↓ Blood volume

↑ Capillary ↓ Effective arterial
hydrostatic pressure blood volume
Renal vasoconstriction
Activation of Chronic hypoxia
renin­­angiotensin Endothelial
­­aldosterone axis damage
↑ Vascular
↑ Renal retention permeability
of Na + and H O
2

↑ Plasma volume
Transudation Exudation
Oedema
FLOWCHART 4.2. Pathogenesis of oedema.

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