Acute Renal Failure

Overview

Definition

Acute kidney injury (AKI) is the sudden loss of kidney function. Kidneys clean waste products from the blood and maintain fluid levels in the body.

Problems can happen:

  • Before blood enters the kidneys
  • Inside the kidneys (most common)
  • When urine leaves the kidneys and moves toward the bladder
Anatomy of the Kidney
Glomerulonephritis
Copyright © Nucleus Medical Media, Inc.

Causes

AKI has many causes:

  • Blood is blocked from going into the kidneys because of:
    • Problems with blood vessels
    • Blood loss
    • Excessive fluid loss— dehydration
    • Infection
  • Problems inside the kidney cause loss of filter because of:
    • Problems after surgery
    • Inflammation
    • Blood clots
    • Medicine side effects
  • Kidney stones
  • Enlarged prostate

Risk Factors

AKI is most common in older adults. Your chances are also higher if you have:

  • Diabetes
  • High blood pressure
  • Kidney, liver, or heart disease
  • Dehydration
  • Bleeding from the stomach or intestines
  • Taken certain medicines
  • Used illegal drugs
  • Problems after surgery or a hospital stay
  • Overused certain nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Some blood pressure or heart medicine when dehydration is also present
  • Blockages, which can happen with benign prostatic hyperplasia or a bladder tumor

SymptomsandDiagnosis

Symptoms

Most people do not have symptoms. In those that have them, AKI may cause:

  • Lower or higher amounts of urine than normal
  • Dark or red urine
  • Fatigue
  • Confusion
  • Nausea or vomiting
  • Muscle weakness
  • Muscle cramps
  • Lack of hunger
  • Swelling
  • Weight gain

Diagnosis

The doctor will ask about your symptoms and health history. You may also have:

  • A physical exam
  • Blood and urine tests—to measure levels of toxins and protein
  • Imaging tests:
    • Kidney ultrasound
    • CT scan
    • MRI scan
    • MRA scan

Treatments

Treatment

Care depends on the cause of AKI and how serious it is. Care may involve:

  • Stopping or changing medicines causing harm to your kidneys
  • Controlling blood pressure and diabetes
  • Avoiding medicine that could be harmful such as NSAIDs common in over-the-counter pain medicine
  • Dietary changes that may limit how much salt and protein you eat
  • IV fluids
  • Dialysis —a machine works for your kidneys by filtering your blood
  • Caring for problems such as kidney stones or infections

Prevention

Most AKI can not be prevented.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (AKI; Acute Kidney Failure; Acute Renal Failure; Acute Renal Insufficiency)

RESOURCES

National Institute of Diabetes and Digestive and Kidney Diseases https//www.niddk.nih.gov 

National Kidney Foundation https://www.kidney.org 

CANADIAN RESOURCES

Health Canada https://www.canada.ca 

The Kidney Foundation of Canada https://www.kidney.ca 

References

Acute kidney injury. EBSCO DynaMed website. Available at:  https://www.dynamed.com/approach-to/acute-kidney-injury-approach-to-the-patient  . Updated May 31, 2019. Accessed September 13, 2019.

Acute kidney injury (AKI). Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/genitourinary-disorders/acute-kidney-injury/acute-kidney-injury-aki. Accessed September 13, 2019.

Kidney failure. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/kidney-disease/kidney-failure. Accessed September 13, 2019.

Rahman M, Shad F, Smith MC. Acute kidney injury: a guide to diagnosis and management. Am Fam Physician. 2012;86(7):631-639.