aetiology

Acute renal failute :
-circulatory shock:
Inadequate cardiac output
Decrease in arterial pressure
Renal blood flow is reduced
GFR and amount of NaCl filtered by the glomeruli are reduced
Decreases the amount of NaCl that must be reabsorbed by the tubules
which uses most of the energy and oxygen consumption by the kidney
Renal blood flow and GFR fall, the requirement for renal oxygen consumption is also reduced.
Renal cells start to become hypoxic
Decrease in renal blood flow
If prolonged – damage or even death of renal cells

-Nephrotoxins :
a toxin with specific destructive properties for the kidneys.
Tubule necrosis
directly affect the glomerulus or the renal tubules
Lead nephropathy, arising from lead poisoning
nephropathy, from ingestion of the solvent carbon tetrachloride
Another toxin may create other substances conditions
causing the cells of these structures to die.
Drugs : antibiotics, analgesics
drug provokes an allergic reaction that destroys the kidneys
converting the hemoglobin of red blood cells into methemoglobin
interfering with the blood's transport of oxygen
Analgesic nephropathy is most prevalent in women over 30.
Uric acid nephropathy
not caused by exposure to an external toxic
arises from the body's overproduction of uric acid
usually in persons with diseases of the lymph nodes or bone marrow

Glomerulonephritis :
Caused by an abnormal immune reaction that damages the glomeruli
Group A beta streptococci
Streptococcal sore throat
Streptococcal tonsillitis
Streptococcal infection of the skin
Antibodies develop against the streptococcal antigen
React with each other to form an insoluble immune complex
Entrapped in the glomeruli
Many cells of the glomeruli begin to proliferate
Large number of WBC become entrapped in the glomeruli
Glomeruli become blocked by this inflammatory reaction
Those that are not blocked become excessively permeable
Allowing both protein and RBC to leak fr the blood of the glomerular capillaries into glomerular filtrate
Complete renal shut down

Burns:
Damaged erythrocytes break down in circulation
Releasing free haemoglobin
Accumulate in the tubule
Causing obstruction
Haemoglobin is toxic to tubular epithelium
Causing inflammation and necrosis

Mechanical obstruction:
-Calculi – Kidney stone
calcium in combination with either oxalate or phosphate
uric acid
amino acid cystine.
may not produce symptoms until they begin to move down the tubes (ureters)
block the flow of urine out of the kidneys
cause infection

-Blood clot
an obstruction in a blood vessel due to a blood clot
travel through the bloodstream
lodge in the renal artery
reduction of blood flow through the renal artery
can impair kidney function.
If prolonged, a complete blockage of blood
Renal failure

Chronic renal failure :
-bilateral pyelonephritis
persistent kidney inflammation that can scar the kidneys
bacteria from outside the body traveling back up the urinary stream
urethra → bladder → kidneys
ascending infection
The flow of urine backward
reflux
instead of a tight valve between the bladder and the ureter, there is a wide opening.
When the bladder contracts during urination, the urine goes both ways,
the urethra→ ureters.
The defect is not easy to correct and those who have it are subject to repeat infections.
from infection or inflammation in the urethra
insertion of catheters or instruments such as cystoscopes for diagnosis or treatment

-Polycystic kidney disease
common inherited cause of kidney failure.
occurs when multiple cysts form on each kidney.
As these cysts enlarge, they block normal kidney function.
If the disease is severe, the kidney can stop working altogether.

-Hypertension:
Chronic increase in pressure stretch the small arterioles and glomeruli
Sclerosis occurs in the glomeruli
Glomerulosclerosis
Leakage of plasma through the intimal membrane of these vessels
Fibrinoid deposits develop in the medial layers of these vessels
Progressive thickening of the vessel wall
Constrict the vessels
In some cases, occludes them
No collateral circulation among the smaller renal arteries, occlusion of one or more of them
Causes destruction of a comparable number of nephrons
Loss of glomeruli and overall nephron function
Decrease in both renal blood flow and GFR


-Diabetes
The body cannot break down glucose (sugar).
filtering function of the kidneys is actually higher
This extra glucose in the blood damages the nephrons
no longer filter blood effectively.
Kidney damage
Leads to hypertension