The technical term for the swelling on the body – IS – EDEMA
– SOMETIMES CALLED OEDEMA….
Generally it means – TOO MUCH FLUID IN THE CELLS OR OUTSIDE
THE CELLS.
TWO TYPES – PITTING – accumulation of fluid in the
extracellular space means outside the cells
-
NON PITTING – accumulation of fluid in the
intracellular fluids mean in the cells
There are four types of mechanisms working in the body which
may cause edema in the body.-.-. ---
1.
Increased hydrostatic
pressure—anything which increases the pressure of water in the blood
vessels, the arterioles or the venules
a.
Kidney failure– failure of the kidney function
== increased retention of the water in the vascular system i.e. blood vessels
== causing increased pressure in arteries
b.
Hypoaldostronism–any condition that alter the
function of the adrenal cortex part of the adrenal medulla gland which secretes
Aldosterone ( a mineralocorticoid whose function is the resorption of sodium
and water and excretion of potassium ions in the distal tubules of the kidneys
) --- aldosterone decreases === there is loss of more water and sodium through
kidneys ==== in turn sodium becomes less in extracellular tissue == edema
c.
Increase of pressure in venules and veins ---
A.
Heart failure – causes back pressure in the
veins – causes backflow of fluid to the periphery – increases pressure in
capillaries === edema
B.
Failure of valves in the veins – causes backflow
and stagnation of fluid in the veins – increases pressure in capillaries ==
edema
C.
Failure of venous pump – for the effective
upward and forward flow of blood in the veins needs effective movements of
skeletal muscles – impart pressure on veins for movements – failure of venous
pump due to paralysis or long standing disorder – fails this pump --- pressure
in capillaries increase == edema
D.
Venous obstruction – any reason like deep vein
thrombosis – increased pressure in capillaries == edema
d.
Decreased arteriolar resistance –
antihypertensive drugs like calcium channel blockers == dilatation of the
arteries prior to capillaries ---- blood moves from the larger diameter artery
to very small capillary === pressure increases manifold ==edema
2.
Decreased proteins in
the blood –proteins are negative charged particle in the blood ----
80% of the proteins in the blood is ALBUMIN – albumin has many functions, the
important is maintaining osmotic pressure in the capillaries …… this pressure
stops the water to go out from the capillaries --- any cause which decreases
the albumin in the blood --- results in edema.
The causes may be –
a.
Loss of albumin in urine – due to any kidney
disease or idiopathic
b.
Loss of proteins from blood – due to wound,
bleedings, abscessesetc.
c.
Failure to manufacture proteins –
A.
Liver failure – (liver is making albumin) – decrease
in albumin – decreased osmotic pressure in capillaries – water leaks out ==
edema
B.
Severe protein malnutrition – decreased albumin
and other proteins – edema
3.
Increased capillary
permeability –causes water to flow out == edema ----- reasons are
===
a.
Any immune reaction – cause release of histamine
– permeability increased –edema
b.
Any inflammation or infection – disrupts the
membranes or alters its functions – increased permeability == edema
c.
Toxins in the blood – attack the membrane and
disrupt them --- edema
d.
Burns – causing disruption – edema
e.
Vitamin deficiency – especially vitamin C, which
is necessary for the formation of the collagen which is the integral part of
the capillary membrane
f.
Prolonged ischemia – when there is no blood
supply to a part for a long periods – capillaries are destroyed there
4.
Obstruction in the
lymphatic drainage – lymphatics have two main functions – one –
immunity, second – drainage of excess body fluids in the extracellular fluids
When there is obstruction in lymph drainage – accumulation of excess
water in extracellular fluids. Causes are ====
a.
Cancer – Hodgkin’s disease or non-Hodgkin’s
disease
b.
Infection – causes accumulation of inflammatory
and immune cells in the lyphatics resulting in obstruction
c.
Surgical removal
d.
Congenital absence or malformation
