Lower back pain is, in 95 percent of cases, caused by muscle and bone-related issues of this area of the spine. The pain associated with the musculoskeletal system tends to remain central in the back. However, there are other causes of pain around the lower back that do not involve the muscles, bones, and joints of this anatomical position and they tend to involve more the sides, or flanks, of this area.

Other organs that need to be considered as potential causes of the pain include the kidneys, ureters (tubes connecting the kidneys to the bladder), the bladder, and the colon. In women, any pathology involving the reproductive organs may also result in pain being experienced around the lower back. Even pathologies affecting organs in other areas of the body may end up causing lower back pain.

Lower back pain - flank painCauses of the lower right and lower left flank pain include the following issues:

  • Kidney-related pathologies such as infections and the development of multiple cysts on the organs.
  • Ureters cramping to try and get rid of any stones lodged in them. Associated symptoms may include pain referring from the flank to the groin.
  • Bladder infections which can cause pain in the lower abdomen that spreads up to the lower back and flank areas as the infection travels towards the kidneys.

Others signs and symptoms that one should look out for to rule out kidney and associated organ pathology causing flank pain include:

  • Fever
  • A frequent need to urinate
  • A burning sensation when urinating
  • The presence of blood in the urine
  • Nausea and vomiting

Gynecological issues that can also result in lower back pain may include the following conditions:

  • Ovarian cysts – where fluid-filled sacs develop on the ovaries and usually enlarge at the time when the affected individual is ovulating.
  • Endometriosis – here, the patient develops tissue found on the lining of the uterus on other areas of the reproductive tract such as the fallopian tubes and the outside of the uterus. During menstruation, these areas also contract to result in lower back pain.
  • Ectopic pregnancy – when a fertilized egg (zygote) implants on another area of the reproductive tract other than the lining of the uterus this is referred to as an ectopic pregnancy. The usual area of involvement is the fallopian tubes and this condition can become an emergency situation if the zygote enlarges enough to cause the tube to rupture.
  • Normal pregnancy – as the fetus develops in the uterus, the ligaments, muscles, tendons, joints, and soft tissues of the pelvis and lower abdomen stretch to accommodate the baby.

Conditions that affect other areas of the body and that may end up resulting in referred pain to the lower back include:

  • Gallbladder disease or gallstones – inflammation or stone obstruction affecting the gallbladder causes right-sided lower rib and shoulder blade pain but may also refer to the lower back.
  • Appendicitis – starts in the lower right groin but may end up spreading throughout the abdomen.
  • Diverticulitis, irritable bowel syndrome (IBS) and constipation – all bowel related issues may cause lower abdominal and pelvic pain but usually end up involving the flanks and lower back as well.
  • In a rare situation, one patient has left flank pain due to obstructed blood flow to a specific section of her lung.1