Bloody urine and lower back pain can be symptoms of kidney infections, kidney stones or prostatitis, reports the Mayo Clinic. These conditions may also cause frequent, urgent or painful urination, and pain that spreads to the groin and lower abdomen.
Kidney infections, also called pyelonephritis, occur when a urinary tract infection spreads from the bladder and urethra up into the kidneys. In addition to urinary symptoms and pain, pyelonephritis can cause fever, chills and malaise, reports WebMD. An infection in the kidneys can spread to the blood and cause serious illness. However, these infections are treatable with antibiotics.
Kidney stones can contribute to kidney infections, since bacteria can grow more rapidly in the kidney stones, according to WebMD. Stones can also block the flow of urine, which increases the risk of a urinary tract infection spreading to the kidneys.
Kidney stones are another cause of blood in the urine and back pain, even without prior pyelonephritis, explains WebMD. Pain from a kidney stone occurs when the stone moves inside the kidney or into the ureter. Kidney stones often pass out of the body naturally. However, a kidney stone may move into a position where it is blocking the flow of urine, which requires medical intervention.