* The kidneys perform essential functions of
removing waste products in the body.
Regulation of the water, electrolyte and acid base
balance
Excretions of products of protein and
nucleic acid metabolism - urea,
creatinine and uric acid
Also an endocrine organ
producing a number of hormones
Argine vasopressin AVP
acts to influence water
balance
contributes to the glucose
supply in fasting state
during gluconeogenesis
Serum creatinine
Creatinine is a waste product that forms when
creatine breaks down. Creatine is a substance
found in muscle and is produced as the result
of normal muscle metabolism
creatinine clearance
The amount of blood the kidneys can make creatinine-free each minute
is called the creatinine clearance. In a healthy adult this is 140mL/min
however this varies with body size
The higher the blood creatinine level, the
lower the estimated GFR and creatinine
clearance.
Volume of plasma = U x V / P V is volume if urine in
litres collected 24 hours U= urine creatinine
concentration P= plasma concentration of creatinine
Certain drugs, including spironolactone, cimetidine, fenofibrate,
trimethoprim and amiloride, decrease creatinine secretion and
thus can reduce creatinine clearance
Rhabdomyolysis is the breakdown of
muscle tissue that leads to the
release of muscle fiber contents into
the blood.
Estimated
GFR
where [sCr] = serum creatinine concentration (µmol/L) and age is measured
in years. This formula is for white males: the result should be multiplied by
0.742 for females and by 1.21 for African Caribbean people
Several formulae have been derived from the Modification of Diet
in Renal Disease (MDRD) study. The ‘four-variable’ formula
Limitations
Eating meat can raise Creatinine levels
Amputes have less creatinine
Urea
Urea is a waste product formed from the
breakdown of proteins. Urea is usually passed
out in the urine. A high blood level of urea
URAEMIA indicates that the kidneys may not be
working properly, or that you are dehydrated
Less reliable indicator of GFR than creatinine
there are many things besides kidney disease that can affect
urea levels such as decreased blood flow to the kidneys as in
congestive heart failure, shock, stress, recent heart attack or
severe burns; bleeding from the gastrointestinal tract; conditions
that cause obstruction of urine flow; or dehydration. Eating high
levels of protein can also affect urea
Sodium
The body uses sodium to control blood pressure and blood
volume. Sodium is also needed for your muscles and nerves
to work properly.
hypernatraemia- High levels- a rise
in serum sodium concentration to a
value exceeding 145 mmol/L
Serum sodium concentration, and hence osmolality, is normally kept from
rising significantly by the release of antidiuretic hormone (ADH) or vasopressin
which limits water losses, and the stimulation of thirst which increases water
intake
Salt works on your kidneys to make your body hold on to more water. This
extra stored water raises your blood pressure and puts strain on your
kidneys, arteries, heart and brain
hyponatraemia-
Hyponatraemia represents a
relative excess of water in
relation to sodium
A low sodium level in the blood may result from excess water or fluid in the body, diluting the
normal amount of sodium so that the concentration appears low. This type of hyponatraemia can
be the result of chronic conditions such as kidney failure (when excess fluid cannot be efficiently
excreted) and congestive heart failure, in which excess fluid accumulates in the body
Lead to odema
Sodium reabsorbed in the proximal tuble 65% and 25% in loop of henle
Potassium
Potassium is crucial to heart function and plays a key role in skeletal and
smooth muscle contraction, making it important for normal digestive and
muscular function
Hypokalemia
Most cases are the result of either diuretic consumption or loss of gastrointestinal (GI) fluids
through persistent vomiting, chronic diarrhoea or laxative abuse. With vomiting, the cause is
not mainly direct loss of potassium but that of chloride causing high levels of aldosterone
which inhibits potassium reabsorption from the kidney tubules
Hyperkalaemia
may occur if your kidneys do not work properly and cannot remove
potassium from your body or if your body's cells release too much
potassium.
Breakdown of red blood cells, called hemolysis Breakdown of muscle
tissue, called rhabdomyolysis Burns, trauma, or other tissue injury
Uncontrolled diabetes Conditions that can affect the kidney's ability to
remove potassium from the body include: Hormonal disorders Lupus
Kidney failure Other kidney diseases
Calcium
It’s essential for blood clotting. It stabilizes blood pressure. It contributes to
normal brain function. It’s critical for communicating essential information
among cells.
Hypercalcemia
Parathyroid glands (four small glands) are located near the thyroid gland in the
neck and regulate parathyroid hormone which in turn regulates calcium in the
blood. When at least one of your parathyroid glands becomes overly active, the
condition is called hyperparathyroidism. This is the leading cause of
hypercalcemia
Cancers e.g. multiple myloma
Kidney stones build up of calcium
Some types of drugs, such as thiazide diuretics, can cause hypercalcemia
because less calcium is excreted and more retained in the body. Other drugs, such
as lithium, cause more PTH to be released
Hypocalcemia
acute pancreatitis, kidney failure, phosphate or calcium infusion,
hypoparathyroidism (most often after surgery), diabetes of the
mother (in the case of infants), spreading cancer, and certain
drugs
Posphate
he body needs phosphorus to build and repair bones and
teeth, help nerves function, and make muscles contract
Hyperphosphatemia
Hyperphosphatemia
Fanconi syndrome (also known as Fanconi's syndrome) is
a disease of the proximal renal tubules[1] of the kidney in
which glucose, amino acids, uric acid, phosphate and
bicarbonate are passed into the urine, instead of being
reabsorbed