Constipation May Trigger Lower Back Pain Through Shared Nerve Pathways, Doctor Says

Constipation can sometimes cause lower back pain, though the relationship works through indirect mechanisms, says Dr Santhosh Rajendran, a junior gastroenterology consultant at SIMS Hospital in Chennai. He notes that nerves from the distal colon join the spinal cord near the thoracic and sacral levels, so when the colon swells, the pain can be felt in the lumbosacral area – a classic case of referred pain. A severe blockage of stool can expand the lower intestine and press on nearby nerves, producing discomfort that resembles sciatica and often eases after the stool is cleared. Sitting on the toilet for long periods in a hunched position adds extra load to the lumbar spine, while repeated straining raises pressure inside spinal discs, which may worsen an existing disc problem rather than create a new one. Dysfunction of the pelvic floor muscles, which help both bowel movements and stabilize the pelvis, can also link constipation and back pain. Rajendran warns that having both symptoms does not prove one caused the other; the link may run the other way or both may stem from a common condition such as hypothyroidism, diabetes, Parkinson’s disease, spinal disorders, or pregnancy. He adds that persistent bowel issues together with back pain could signal serious problems like cauda equina syndrome, which requires a doctor to check anal muscle tone. In short, constipation may play a role in back pain for some people, but it is not the sole explanation.

Context

Referred pain occurs when organs share spinal nerve segments, so discomfort in the gut can be felt in the back. The pelvic floor also supports the lower spine, making its weakness a possible factor in both constipation and backache.