Lower back pain is a common experience, often attributed to musculoskeletal issues like muscle strain or disc problems. However, discomfort in this area can sometimes signal conditions originating from internal organs, a phenomenon known as “referred pain.” Referred pain occurs when the brain interprets pain signals from an internal organ as coming from a different part of the body, typically an area supplied by the same spinal nerves. Recognizing that pain can stem from non-musculoskeletal sources is important for accurate diagnosis.
Kidneys and Urinary Tract
Conditions affecting the kidneys and urinary tract can manifest as lower back pain. Kidney stones frequently cause sharp, severe pain that often begins in the flank region and radiates towards the lower back or groin. This pain can be intensely colicky, meaning it comes in waves as the stone attempts to move through the narrow ureters. Nausea, vomiting, painful urination, and blood in the urine often accompany this discomfort.
Kidney infections, or pyelonephritis, also present with lower back or flank pain. This pain is accompanied by systemic symptoms such as fever and chills. The infection usually starts in the lower urinary tract and ascends to the kidneys, causing inflammation and pain. Severe bladder infections, known as cystitis, can also contribute to lower back discomfort, though often less intense than kidney-related pain.
Digestive System Organs
Various organs within the digestive system can refer pain to the lower back. Pancreatitis, an inflammation of the pancreas, often causes upper abdominal pain that radiates to the back. Inflammatory bowel diseases (IBD), including Crohn’s disease and ulcerative colitis, can also cause lower back pain. This occurs because the inflammation associated with these conditions can spread to nearby joints, including those in the spine or sacroiliac joints.
Diverticulitis, characterized by inflammation of small pouches in the colon, causes pain in the lower left abdomen but can sometimes refer to the lower back. The inflammation can irritate surrounding tissues and nerves, leading to this referred sensation. Appendicitis, an inflammation of the appendix, can also present with atypical lower back pain. If the appendix is positioned behind the colon, its inflammation can directly irritate nerves that refer pain to the lower back or pelvis.
Reproductive System Organs
Conditions affecting reproductive organs can cause lower back pain. In females, endometriosis, where uterine-like tissue grows outside the uterus, causes chronic pelvic pain radiating to the lower back. Uterine fibroids, non-cancerous growths, can lead to lower back discomfort if they press on surrounding structures. Ovarian cysts, fluid-filled sacs, may cause lower back pain, especially if large. Pelvic inflammatory disease (PID), an infection, also contributes to lower back pain alongside pelvic and abdominal tenderness.
In males, prostate issues are a common source of referred lower back pain. Prostatitis, an inflammation or infection of the prostate gland, can cause pain in the lower back, groin, or pelvic area. It may be accompanied by urinary problems such as frequent or painful urination. Both acute and chronic forms of prostatitis can lead to these symptoms.
Vascular System Considerations
The abdominal aorta is another potential source of referred lower back pain. An abdominal aortic aneurysm (AAA) involves a weakened, bulging area in this artery. While many AAAs cause no symptoms, a rapidly expanding or rupturing aneurysm can cause sudden, severe, and persistent pain in the lower back. This pain results from the pressure the aneurysm exerts on surrounding structures, including the spine. A ruptured AAA is a life-threatening medical emergency, often accompanied by symptoms such as a pulsing sensation in the abdomen, dizziness, or a sudden drop in blood pressure.