What is back pain?

People may feel the pain almost anywhere in the back, from the base of the neck down to the tailbone. The pain may originate from any of the structures of the spine, including the

  • vertebrae (bones of the spine),
  • discs between the bones,
  • nerves that exit the back to the rest of the body, and
  • muscles and ligaments that support the back.

Pain can also begin elsewhere and radiate to the back. Some examples include the following:

What is kidney pain?

Kidney pain is a specific type of back pain arising from the kidney and causing symptoms in the flank. The flank is a rectangular area in the back from the lower rib cage to the iliac crest (the top bone of the pelvis) and the spine to the lateral part of the body.

What are the causes and risk factors of kidney pain and back pain?

Back pain

Back pain has numerous causes, depending upon the involved structure. Pain and inflammation of the muscles and ligaments in the back from an acute injury, or from chronic overuse, can cause significant pain.

Osteoporosis and decreased bone density can cause spontaneous compression fractures of vertebrae of the spine. Fractures (broken bones) may also occur due to trauma and acute injury.

The spinal nerves that exit the back can become irritated for a variety of reasons that cause the nerve to be inflamed. These include ruptured discs and arthritis of the back and narrowing of the spaces between the vertebral bodies. A common example is sciatica, inflammation of the sciatic nerve that causes pain in the back that may radiate down the leg.

Tumors can affect all structures that make up the back and cause pain. Those tumors may be benign or malignant. They can be primary, arising from the back structure, or metastatic, having spread from another part of the body.

All the structures located in the area of the back have the potential to become infected and cause pain. Some examples include the following:

  • Shingles, a complication of chickenpox, which is an infection of the nerves
  • Osteomyelitis, bone infection of the vertebral body
  • Discitis, infection of the discs located between the vertebral bodies

Kidney pain

Inflammation of the kidney causes kidney pain and is most often due to a kidney infection, bleeding inside or surrounding the kidney, or obstruction of the kidney.

Kidney infection, or pyelonephritis = pyelo (central structure of the kidney called the renal pelvis) + neph or renal (kidney) + itis (inflammation), can be a result of a bladder infection in which the bacteria climb up the ureter to invade the kidney. Infection may also enter the kidney through the bloodstream should there be an infection elsewhere in the body.

Bleeding in and around the kidney may occur because of an injury (trauma) or may occur spontaneously in people who take anticoagulation (blood thinning) medication. Kidney tumors may also cause bleeding in the kidney.

Kidney pain from obstruction is most often due to kidney stones, but blood clots and tumors can also prevent urine from draining from the kidney down the ureter into the bladder. The kidney continues to make urine, even if it can’t easily drain. This causes the kidney to swell and become inflamed, causing pain. Too much swelling and inflammation within the kidney may cause that one kidney to stop working. Fortunately, most people have another kidney to help remove waste from the body.