Acute Renal (kidney) Failure
The kidneys are located on either side of the spine above the waist. They make urine by filtering waste products and water from the blood, control the balance of salts and water in the body, and help regulate blood pressure. As long as a person has the equivalent of one kidney working, their body can cope.
What do the kidneys do ?
The respiratory system consists of the lungs, airways and blood vessels. The function of the respiratory system is to absorb oxygen into the body and to remove carbon dioxide from the body. A normal breath requires a complex coordination between the nervous system (brain & spinal cord) and the muscles of breathing (including the diaphragm and muscles between the ribs).
‘Acute renal failure’ is the sudden shutdown of both kidneys. The kidneys are no longer able to make urine, rid the body of wastes, or keep a healthy balance of salts such as sodium and potassium.
Tiny blood vessels in the kidneys filter the wastes from the blood that flows through them. The kidneys need good blood flow for this to work properly, and ‘acute renal failure’ can occur if the kidneys are not getting enough blood flow. People who have been badly burned, have had a big heart attack, have lost a lot of blood, or have a severe infection commonly have reduced blood flow to the kidneys, and thus can suffer kidney failure.
Failure can also occur when disease, drugs or poisons injure the kidneys. Examples of these include:
- Complete blockage of the outflow of urine by kidney stones or enlarged prostate
- Inflammation that affects many organs in the body, including the kidneys (eg Systemic Lupus Erythematosis)
- Anti-arthritis drugs can occasionally cause kidney damage
What are the symptoms?
Most symptoms are not specific to kidney failure, and can occur for other reasons. They might include:
- Drowsiness and fatigue
- Loss of appetite
- Muscle cramps and weakness
- Nausea and vomiting
- Reduced urine output
- Swelling of the feet and ankles
How is acute renal failure diagnosed?
Reduction in the amount of urine is usually the most important clue that the kidneys are not working properly. The levels of waste products are measured in the blood (‘urea’ and ‘creatinine’), and high levels of these mean that the kidneys are failing to work. Other blood and urine tests and X-rays or ultrasound tests are then required to understand why the kidneys are failing. The urine can be examined under a microscope, for example, to look for inflammatory cells or bacteria. Ultrasound of the kidneys is frequently used to detect blockage of the urine outflow (because it can show the enlargement of tubes running between the kidney and bladder that follows blockage).
How is acute renal failure treated?
If the kidney failure has been caused by a fall in blood flow to the kidneys, then the most important thing is treatment of the cause for the poor blood flow. If blood flow can be restored, then otherwise healthy kidneys will start working again over a period of days to weeks.
If a disease, such as ‘glomerulonephritis’, has directly affected the kidneys then that disease needs to be treated before the kidney function can start to improve.
In the meantime, if the kidneys have failed completely, then treatment with an artificial kidney machine is essential and life-saving, while treatment for the underlying condition is undertaken. The treatment is called ‘dialysis’.
How does the artificial kidney machine work?
A tube (‘dual-lumen catheter’) is placed into one of the patient’s veins to transport the patient’s blood to-and-from the kidney machine. Often one of the large veins in the groin is used. As the blood flows through the artificial kidney, wastes and excess water and salts are removed, and the blood then returns to the patient. Sometimes drugs (such as ‘heparin’) are given to prevent the patient’s blood clotting inside the artificial kidney.
Occasionally dialysis is associated with infection or bleeding.
What happens if the kidneys do not recover?
Most previously healthy kidneys will recover if the cause for the kidney failure is successfully treated. Often the recovery is complete, even if it takes months. The younger a person is, the more likely their kidneys will recover.
Occasionally the damage becomes permanent, despite successful treatment of the underlying condition. If the damage is very severe, long-term dialysis or a kidney transplant is required. In Australia, approximately one person in ten with complete kidney failure will need long- term dialysis after a stay in Intensive Care.
Sometimes treatment of the underlying condition is unsuccessful, and the condition and the kidney failure cause death.
For more information
Australian Kidney Foundation http://www.kidney.org.au/
The information contained on this page is general in nature and therefore cannot reflect individual patient variation. In addition it reflects Australian intensive care practice which may differ from other countries. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. ICCMU attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.
- First publishing August 2008
- Written by Dr Louise Cole Staff Specialist ICU, Nepean Hospital, Penrith NSW, Australia.