Hundreds of thousands of people are diagnosed with kidney failure in the United States each year. While the majority of kidney failure cases develop as end-stage renal disease (ESRD), the last stage of chronic kidney disease (CKD), about 7% of kidney failure cases are the result of acute kidney injury (AKI). Learn the differences between kidney failure from CKD and AKI.*

What is kidney failure?

Kidney failure is when the kidneys are functioning at less than 15% (eGFR of less than 15). When your kidneys are not filtering out wastes, toxins, and excess fluids, these build up in your blood and tissues and damage other major organs, including the brain, heart, and lungs. 

Causes of kidney failure 

CKD

The three primary causes of CKD are:

• Diabetes, 
• Hypertension (high blood pressure), and 
• Heart disease.  

All of these conditions damage the blood vessels, tissues, and filters inside the kidneys, along with surrounding blood vessels, tissues, and organs. The conditions are often also caused by kidney disease, resulting in a cycle of progressive damage that currently has no cure. 

CKD-related kidney failure can also result from:

• Glomerulonephritis (inflammation of kidney filters),
• Polycystic kidney disease, 
• Genetic anomalies, 
• Autoimmune diseases (lupus, sarcoidosis, etc.), and
• Obstructions (tumors, kidney stones).

Early stages of CKD often have no noticeable symptoms. The disease progresses gradually, and it can be years, even decades, before kidney failure occurs.  

AKI

AKI, also called acute renal failure, can develop quickly, over a matter of hours, days, or weeks. It can result from:

• Reduced blood flow to the kidneys, caused by:
  • Low blood pressure 
  • Blood loss 
  • Cardiovascular issues 
• Liver or heart failure 
• Severe allergic reactions, injuries, or burns
• Underlying conditions such as:
  • Infections, like sepsis
  • Cancer
• Urinary blockages from tumors, kidney stones, blood clots, or an enlarged prostate
• Major surgical procedures

AKI often develops in patients who are in the hospital being treated for another health issue, especially if they are in the ICU. 

Symptoms of kidney failure

ESRD

People with CKD don’t usually experience symptoms until stage 3b or 4. Stage 4 (eGFR between 15 and 29), is when your kidney doctor will usually broach the subject of impending kidney failure, discuss your treatment options, and ask how you would like to proceed. 

Kidney failure in stage 5 CKD can manifest in such symptoms as:

• Loss of appetite
• Muscle twitches and cramps
• Continuously itchy skin
• Sleep disturbance
• Uncontrollable hypertension 

AKI does not always announce itself with symptoms other than less frequent urination.  

Some people, however, may experience:

• Brain fog
• Breathlessness and/or chest pain
• Edema (fluid buildup), in the legs and ankles, and around the eyes
• Fatigue
• Nausea  

Acute kidney failure can lead to seizures and/or coma. 

Treatment of kidney failure

Once you have been diagnosed with CKD, treatment usually involves:

• Managing your diabetes, high cholesterol, and/or hypertension
• Working with a renal dietitian
• Adjusting your medications if necessary 
• Attainging and maintaining a healthy weight 
• Quitting smoking

These steps can help slow the disease progression, and can even halt it if started in stages 1 or 2. By stage 3, the damage is advanced, and while progression can still be slowed, it cannot be halted or reversed. Kidney failure from CKD is treated with dialysis or kidney transplantation. 

Depending on its specific cause and the extent of damage the kidney has sustained, AKI can be treated and the damage reversed. Treatment of AKI may include:

• Medication to control blood pressure,
• Controlling the levels of electrolytes in your blood,
• Diuretics, to promote urination and rid your body of excess fluid.

Severe AKI may require short-term dialysis until your kidneys are healed.

*Felman, A. (2023, October 11). What to know about acute vs. chronic renal failure. Medical News Today. https://www.medicalnewstoday.com/articles/acute-vs-chronic-renal-failure