What is acute kidney injury?
Acute kidney injury (AKI) is not new and is in fact described in the bible! It used to be known as acute kidney or renal failure. It is a clinical syndrome characterized by a rapid deterioration of kidney function which results in the build up of waste products and fluid in the body.
It is a clinical syndrome characterized by a rapid deterioration of kidney function which results in the build up of waste products and fluid in the body.
So why acute kidney injury? This term has replaced acute renal failure to emphasize the point that the process of kidney damage is a continuum with kidney injury occurring long before kidney function is lost.
Consequently, the severity of renal damage may range from slight functional impairment to complete loss of renal function requiring renal replacement therapy.
AKI is diagnosed by a rise in serum creatinine, a fall in urine output or both according to the internationally agreed criteria of the KDIGO classification.
There are numerous causes of AKI. A recent prevalence study by the International Society of Nephrology confirmed that there were marked differences between industrialized countries and resource restricted areas of the world.
Why is Acute Kidney Infection important?
- AKI is very common. It affects about 1 in 10 patients in hospital and over half of those in the Intensive Care Unit (ICU). The incidence of AKI is rising. This is the result of greater awareness and recognition but also due to an aging population, increasing prevalence of cardiovascular disease and chronic kidney disease (CKD), advances in modern medicine and more frequent use of high-risk procedures.
- AKI can have both immediately recognizable effects like fluid overload with swelling and breathlessness, as well as less noticeable or delayed consequences like electrolyte disturbances and impaired immunity.
- AKI can affect other organs, including heart, lungs, liver and brain and cause multi-organ dysfunction. In some ways it is best to think of AKI as a systemic process rather than it just being a kidney problem.
- AKI is associated with an increased risk of dying. The AKI-EPI study showed that mortality was particularly high in patients with more severe AKI.
- AKI also leads to long-term effects on health. Patients who survive an episode of AKI have an increased risk of developing CKD and end-stage renal failure, cardiovascular problems, strokes and fractures. In addition, their physical strength and quality of life is often impaired compared to patients who have not had AKI.
- AKI is expensive and associated with high health-care costs as a result of longer hospitalizations, unplanned admissions to the intensive care unit and re-hospitalizations.
What are the healthcare needs of patients with AKI?
The most important approach for AKI is to treat its cause as there is currently no specific therapy to treat AKI itself.
The most important approach for AKI is to treat its cause as there is currently no specific therapy to treat AKI itself. Patients need appropriate general care, avoidance of further nephrotoxic insults and most importantly treatment of the underlying illness which led to AKI.
This may be very straightforward such as adequate volume replacement for diarrhoea, which is the most frequent cause for AKI in developing countries, or more complicated in case of sepsis induced AKI in the ICU.
If this general approach does not result in recovery of kidney function, renal replacement therapy may be necessary until renal function recovers.
In some patients, AKI may be an end-of life event and such patients require appropriative palliative care.
What are the urgent needs?
AKI is often diagnosed late because the blood tests used to monitor kidney function take 24 to 48 hours before they rise so there is an urgent need for tests which diagnose AKI earlier, in particular during critical illness. There are some tests available which may be of help in the future.
Currently the management of AKI is supportive only. There is a need for specific therapies which may reverse the acute damaging process and/or induce renal repair.
Where drugs are excreted by the kidney dosing is particularly challenging in patients with AKI especially if renal function changes quickly. As a result, patients with AKI are at risk of under- and overdosing. More information is urgently needed to inform appropriate drug dosing.