Discomfort in the lower left back often leads to questions about its cause. Understanding the organs in this region can help identify potential sources of pain or other sensations.
Organs on Your Lower Left Side
The lower left side of the back houses several organs. The left kidney, located just below the rib cage, filters waste and excess fluids from the blood, maintains electrolyte balance, and regulates blood pressure. The left adrenal gland, a small endocrine gland, sits directly atop the left kidney.
Within the abdominal cavity, the descending and sigmoid colon, parts of the large intestine, occupy the left side. The descending colon stores waste before it moves into the sigmoid colon for elimination. These sections absorb water and solidify stool. The spleen, located higher under the left rib cage, can also cause referred pain to the back. This organ supports the immune system by filtering blood, removing old red blood cells, and producing white blood cells to fight infections.
Potential Causes of Discomfort
Pain from the left kidney may be a constant dull ache or sharp, wave-like sensations in the back or side, which may spread to the groin. Kidney stones, hard mineral deposits, cause intense pain as they move through the urinary tract. Kidney infections (pyelonephritis) may cause similar back pain with fever, chills, nausea, vomiting, frequent urination, or burning during urination.
Discomfort in the lower left back may also stem from colon issues. Diverticulitis, an inflammation of small pouches in the colon lining, often causes pain in the lower left abdomen that can radiate to the back. Symptoms often include abdominal tenderness, altered bowel habits, fever, or nausea. Irritable Bowel Syndrome (IBS), a functional gastrointestinal disorder, can also lead to lower back pain from gas pressure, colon spasms, or swollen bowels. Additionally, constipation, a buildup of stool, may pressure nerves in the lower spine, causing a dull ache in the lower back.
While less common for direct back pain, an enlarged spleen (splenomegaly) can cause upper left abdominal discomfort that might extend to the left shoulder or back. Beyond organ-specific issues, musculoskeletal problems are common causes of lower back pain. Muscle strains, sprains, or spinal conditions like herniated discs or sciatica can result from overuse, improper lifting, or poor posture.
When to Consult a Doctor
Consult a doctor if lower left back pain is severe, persistent, or accompanied by other concerning symptoms. Seek medical attention if the pain lasts longer than a few weeks or progressively worsens.
Seek immediate medical attention if the pain is accompanied by fever, chills, nausea, or vomiting. Other warning signs include blood in the urine or stool, unexplained weight loss, significant changes in bowel or bladder control, dizziness, fainting, or new numbness or weakness in the legs. These symptoms can indicate a more serious underlying condition requiring prompt diagnosis and treatment.