Chronic Kidney Disease

by Diane W. Shannon, MD, MPH

Chronic kidney disease (CKD) is a condition in which the kidneys are not working properly. It is caused by damage to tiny structures within the kidneys called nephrons. In the early stages, CKD does not cause problems. As a result, most people don’t know they have a problem.

The kidneys are bean-shaped organs in the lower back just below the rib cage. Each one is about the size of a fist. The two kidneys filter wastes from the blood and make urine. They also catch needed substances and return them to the bloodstream. If the kidneys don’t work well, wastes build up in the blood. The kidneys also keep the balance of water in the body. They release hormones that keep the bones strong, control blood pressure, and help the body make red blood cells. If your kidneys stop working, your bones may become weak, your blood pressure may go up, and your red blood cell count may drop.

Anatomy of the Kidneys

Stages

CKD is a progressive condition. Doctors use stages to describe how serious it is. The stage is based on the glomerular filtration rate (GFR).

Stage	Glomerular Filtration Rate (GFR)
1	Over 90 mL/min (normal)
2	60 to 89 mL/min (mild decrease)
3	30 to 59 mL/min (moderate decrease)
4	15 to 29 mL/min (severe decrease)
5	under 15 mL/min (kidney failure or end-stage renal disease)

Causes

The two most common causes of CKD are diabetes and high blood pressure.

Diabetes type 1 and type 2 occur when the body doesn’t process the sugar in the blood well. The amount of sugar in the blood increases. High blood glucose damages the kidneys, the heart, blood vessels, and eyes.
High blood pressure occurs when there is high pressure within the arteries of the body. High blood pressure damages the kidneys.

Other conditions that can cause CKD include:

Intrinsic kidney disease such as polycystic kidney disease or glomerulonephritis

Glomerular disease leading to kidney damage

Kidney tubule disorders

Diseases of the immune system such as systemic lupus erythematosus

Kidney stones, tumors, or an enlarged prostate can lead to obstructive kidney diseases

Recurrent urinary tract infections

Toxic exposures

Prolonged use of medicines, such as ibuprofen, aspirin, or phenacetin

Renal artery stenosis

Viruses such as hepatitis B, hepatitis C, or HIV

Obstructive sleep apnea

Tubular interstitial nephritis

Complications

CKD can cause many complications such as:

High blood pressure
Coronary artery disease and heart attacks
High cholesterol levels in the blood
Weak bones
Low red blood cell count— anemia
Weak immune system

References:

About chronic kidney disease. National Kidney Foundation website. Available at: https://www.kidney.org/atoz/content/about-chronic-kidney-disease. Updated February 15, 2017. Accessed June 15, 2018.

Chronic kidney disease. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/genitourinary-disorders/chronic-kidney-disease/chronic-kidney-disease. Updated March 2017. Accessed June 15, 2018.

Chronic kidney disease (CKD). Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/condition/chronic-kidney-disease-ckd. Updated August 9, 2017. Accessed June 15, 2018.

Chronic kidney disease (CKD) in adults. EBSCO DynaMed Plus website. Available at: http://www.dynamed... . Updated May 14, 2018. Accessed June 18, 2018.

What is chronic kidney disease? National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd/what-is-chronic-kidney-disease. Updated June 2017. Accessed June 15, 2018.

8/10/2015 DynaMed Plus Systematic Literature Surveillance http://www.dynamed... : Molnar M, Mucsi I, Novak M, et al. Association of incident obstructive sleep apnoea with outcomes in a large cohort of US veterans. Thorax 2015;70(9):888-895.

Last reviewed May 2018 by EBSCO Medical Review Board Adrienne Carmack, MD
Last Updated: 06/15/2018

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