Acute Kidney Injury

Many Critical Care Patients Are at Risk for Acute Kidney Injury

The condition can result in loss of kidney function in just 1-2 days

Acute kidney injury (AKI) is characterized by an abrupt loss of kidney function that usually develops within just a few hours to a few days. AKI occurs when the kidneys suddenly become unable to filter water and waste products from the body and is most often seen in patients who have been hospitalized for other critical conditions or in patients who require surgery.

AKI is a serious condition that is estimated to affect between 7 and 18 percent of hospital inpatients1. Mortality associated with AKI is significant and is responsible for approximately 2 million deaths annually worldwide2.

Major causes of acute kidney injury include:
• Decreased blood flow to the kidneys e.g. severe bleeding or major surgery
• Direct damage to the kidneys e.g. drug toxicity, contrast dye or sepsis
• Blockage of the urinary tract e.g. kidney stones or enlarged prostate

The symptoms of AKI vary from patient to patient but usually include lethargy, weakness, muscle cramps, nausea and vomiting. The main laboratory indicators are an increase in serum creatinine levels and a reduction in urine output. Other useful diagnostic tests include urine microscopy, osmolality, and level of blood urea nitrogen (BUN). Electrolyte levels may also be used to help detect further complications along with imaging tests that can identify possible obstructions in the kidney.

The prognosis for AKI depends on the severity of the disease, the degree of pre-existing kidney disease, and how long the causative factors were present, as well as the patient’s age and overall health. Patients with uncomplicated AKI have a mortality rate of approximately 10%. In more severe cases, when renal replacement therapy (RRT) is required, the mortality rate can be as high as 80%.

1. Lewington AJP, Certa J, Mehta RL Raising Awareness of Acute Kidney Injury: A Global Perspective of a Silent Killer. Kidney Int. 2013;84(3):457-467
2. Chawla L, Kimmel P. Acute Kidney Injury and Chronic Kidney Disease. Kidney Int. 2012;82(5):516-524.