Understanding Kidney Disease -- the Basics

What Is Kidney Disease?

The kidneys are two organs located in your midsection on either side of your spine in the middle of your back, just above the waist. They clean your blood, keep the balance of salt and minerals in your blood, and help control blood pressure.

When your kidneys are damaged, waste products and fluid can build up in your body, causing swelling in your ankles, vomiting, weakness, poor sleep, and shortness of breath. If you don't treat them, diseased kidneys may eventually stop working completely. Loss of kidney function is a serious -- and potentially fatal -- condition.

Healthy kidneys:

• Maintain a balance of water and minerals, such as sodium, potassium, and phosphorus, in your blood
• Remove waste by-products from your blood after digestion, muscle activity, and exposure to chemicals or medications
• Make renin, an enzyme that helps regulate blood pressure
• Make erythropoietin, which stimulates red blood cell production
• Make an active form of vitamin D, needed for bone health

• What Causes Acute Kidney Injury?

  Doctors call the sudden loss of kidney function "acute kidney injury" or "acute renal failure" (ARF). It has three main causes:
  • Lack of blood flow to the kidneys
  • Direct damage to the kidneys themselves
  • Urine backed up in the kidneys
  These can happen when you:
  • Have a traumatic injury with blood loss
  • Are dehydrated
  • Go into shock during a severe infection called sepsis
  • Have a blocked urine flow, which can happen with an enlarged prostate
  • Take specific drugs or are around certain toxins
  • Get complications with a pregnancy, such as eclampsia and pre-eclampsia, or related HELLP Syndrome
  Marathon runners and other athletes who don't drink enough fluids while competing in long-distance endurance events may get acute renal failure because of a sudden breakdown of muscle tissue. This releases a large amount of protein into the bloodstream called myoglobin that can damage the kidneys.