Acute renal failure is caused by a variety of different disorders and
occurs in a wide range of clinical settings.
In clinical practice, acute renal failure due to low blood pressure is
one of the most common forms of acute renal failure, it may account for
40 to 80 % of all cases, and if prolonged, can lead to chronic renal
Causes of acute renal failure
The most common cause of acute renal failure in hospital (75 %) is acute tubular necrosis.
The different clinical settings are:
- 30% Low blood pressure (hypotension) - due to whatever reason e.g. haemorrhage, fluid loss etc.
- 19% Nephrotoxins- like specific antibiotics (e.g.
aminoglycosides), X-ray dyes, organic solvents, heavy metals, pain
- 15% due to severe infection(septicaemia)
- 3% rhabdomyolysis- break down of muscle protein which overloads/blocks the
- 7% Glomerulonephritis
- 9% interstitial nephritis
- 4% vascular disease
- trauma or post-operative
- Dehydration is also a significant risk factor for the development of acute renal
- Obstructive renal failure (uropathy)- obstruction is a less common
cause of acute renal failure and is encountered in 2 - 10 % of all
cases and more common in older men with prostatic disease and patients
- Renal artery occlusion/renal artery stenosis may result in acute renal
Patients at greatest risk of acute renal failure comprise a high-risk
group: postsurgical (aortic aneurysm, bowel resection, cardiac surgery,
other), trauma (road traffic accident, burns), and medical (sepsis,
poor cardiac output,
The mortality rate, previously up to 90%, has declined with the
introduction of haemodialysis to 50 Ð 60% . Although there has been
little further improvement in the overall mortality rate in the past 40
years there have been significant improvements that have occurred in
survival among patients with specific causative disorders e.g.
Duraemic syndrome and multiple myeloma.
Causes of death are now attributable to infection, cardiorespiratory
disease, the underlying causative disorder and associated complications.
Continuous renal replacement therapy methods have been widely used in
the past decade for acute renal failure in critically ill patients who
need intensive care; in many of these patients acute renal failure
occurs in association with multiple organ system failure. There is no
proof that continuous renal replacement therapy techniques improve
outcome in terms of patient survival among such patients, and it may be
that renal failure as such does not contribute sufficiently to death in
multiple organ system failure for there to be a demonstrable difference
between patients treated with continuous renal replacement therapy and
Prognosis for recovery of renal function
Prognosis in terms of recovery of renal function has been less
extensively studied than mortality.
Several studies have indicated that recovery of renal function may be
affected by both age and the nature of the causative disorder.
In general, the following statements can be made regarding prognosis in acute renal failure:
- Reversible pre- (e.g. dehydration, haemorrhage, fluid loss) and
postrenal forms (e.g. obstructed kidneys) of acute renal failure have a
better prognosis than acute damage to the kidney tubes.
- Patients with few or no added clinical complications have a very favourable survival rate, greater than 90%
- There is an inverse relationship between the number of
systems/organs failing and the likelihood of acute renal failure
- Selected complications such as respiratory failure, cardiac failure, se