Numerous conditions can cause side or flank pain in the lower abdomen. According to MedlinePlus, a service of the National Institutes of Health, abdominal pain can occur in any abdominal quadrant. Problems in and around the abdomen can also cause side or flank pain in the lower abdomen. Traumatic injuries, overuse injuries and certain medical conditions are all possible causes of lower flank pain. Lower flank pain can range from uncomfortable to disabling, in severe cases.
Diverticulitis
Diverticulitis can cause flank pain in the lower abdomen. According to the Merck Manuals Online Medical Library, diverticulitis is inflammation or infection of one or more diverticula -- an out-pouching or sac on the outside of the colon. One of the most common locations for diverticulae and diverticulitis is the sigmoid colon in the lower left abdominal quadrant. Diverticulitis commonly affects people over of the age of 40, although it can manifest in younger people as well. Common signs and symptoms associated with diverticulitis include pain and tenderness in the left lower part of the abdomen and flank, fever, elevated white blood cell count, nausea and diarrhea. The Merck Manuals states that certain health complications can be caused by diverticulitis, such as the formation of a fistula or a channel between the large intestine and other organs. Fistulas may form between the sigmoid colon and the bladder.
Abdominal Muscle Strains
Abdominal muscle strains can cause side pain in the lower abdomen. Abdominal muscle strains occur when abdominal wall muscles -- rectus abdominis, external and internal obliques and transversus abdominis -- are stretched or torn. The most common cause of abdominal muscle strains is forceful activity, such as that experienced during certain sports, activities or occupations. Although most abdominal strains affect the rectus abdominis muscle, which is located in the middle of the abdomen, strains of the other abdominal muscles may cause pain or discomfort in the lower flank. Common signs and symptoms associated with abdominal muscle strains include tenderness and swelling in the affected area, muscle guarding or spasm and reduced strength in the involved muscle or muscles.
Renal Calculi
Renal calculi, also known as kidney stones, can cause side pain in the lower abdomen. Renal calculi, hard deposits that manifest within the kidneys, are composed of mineral and acid salts. One of the most common causes of kidney stones is dehydration. Dehydration causes the urine to become concentrated, and concentrated urine allows certain minerals to bind together, forming stones. Although passing a kidney stone can be extremely painful, it does not cause irreversible damage. In fact, beyond taking medication to blunt the pain and drinking a sufficient amount of water, most kidney stones do not require treatment. Common signs and symptoms associated with kidney stones include severe back and flank pain, pain that moves around the torso and into the groin over time, painful urination, blood in the urine, nausea and vomiting and the unrelenting urge to urinate.
