Why Do We Need Two Kidneys?

Reviewed on 3/11/2022
Illustration of kidneys
Even though people can actually survive with only one kidney, we have two and it is not fully understood why. Some possible reasons include only needing 30 percent kidney function for normal survival and you have an extra reserve of kidney mass in case of injury to a kidney.

The kidneys are bean-shaped organs about the size of a fist located in the back of the abdomen, just under the ribcage, on each side of the spine. The kidneys are part of the urinary tract and they function to remove excess fluids and waste from the body. 

People can actually survive with only one kidney, as is the case in people born with only one kidney (unilateral renal agenesis) or people who donate a kidney. In fact, if you donate or lose a kidney, you still have 60 to 65 percent function. People only need 30 percent kidney function for normal survival. 

It is not completely understood why we have two kidneys, but theories include: 

  • There is extra reserve of kidney mass in case of injury to a kidney
  • Most animals who live on land have what is called “bilateral symmetry,” that is, everything is the same on both sides: two arms, two legs, two eyes, two ears, two lobes of the lungs, etc. and kidneys are an extension of this symmetry 

What Are Types of Kidney Problems?

Common types of kidney problems include:

What Are Symptoms of Kidney Problems?

Signs and symptoms something is wrong with the kidneys include: 

What Causes Kidney Problems?

Causes of kidney problems include: 

How Are Kidney Problems Diagnosed?

In addition to a physical examination and patient history, tests used to diagnose the cause of the kidney problems include:

What Is the Treatment for Kidney Problems?

Treatment for kidney problems depends on the cause. 

Medications may help relieve pain, such as:

  • Acetaminophen (Tylenol)
  • Morphine (for painful kidney stones)
  • Patients with known kidney problems should be cautious with pain medications that are filtered through the kidneys, because this may cause additional damage to the kidneys

Kidney infections (pyelonephritis) or urinary tract infections (UTIs) are usually treated with antibiotics.

Kidney stones may need to be surgically removed in some cases. 

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Reviewed on 3/11/2022
References
Image Source: iStock Images

https://www.kidneyfund.org/kidney-disease/kidney-problems/kidney-pain.html

https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-infection-pyelonephritis

https://www.urologyhealth.org/urologic-conditions/kidney-stones

https://www.kidney.org/atoz/content/kidneydiscauses

https://www.uptodate.com/contents/anemia-caused-by-low-iron-in-adults-beyond-the-basics?search=iron%20deficiency%20anemia&source=search_result&selectedTitle=4~150&usage_type=default&display_rank=4

https://ukrocharity.org/2010/07/q-a-why-do-we-have-two-kidneys/

https://www.piedmont.org/living-better/the-kidneys-how-they-work-and-what-happens-when-they-dont

https://www.latrobe.edu.au/news/articles/2018/opinion/why-do-we-have-two-kidneys