One reason for blood in urine is a bladder infection, which causes a burning sensation when passing urine. An infant with such an infection experiences fever, irritability and a low appetite. In older children, the infection causes lower belly pain, pain while urinating and fever. The presence of blood in urine may indicate kidney infections, with symptoms that range from fever to chills and lower back pain, according to WebMD.
Other causes include glomerulonephritis, which is a disease that impairs the filtering function of kidneys, an enlarged prostate, genetic diseases, such as sickle cell anemia, and tumors in the prostate or bladder, states WebMD. People who take blood-thinning medications, such as aspirin, heparin and phenazopyridine, are at risk of passing bloody urine, while an accident may cause kidney contusions and result in bleeding.
Blood in urine occurs in people with bladder cancer, which also causes painful and frequent urination and back and pelvic pain, explains Mayo Clinic. Patients may detect blood in the form of cola-colored urine, or a microscopic exam may detect the blood, notes WebMD. Kidney stones, which are hard mineral build-ups in kidneys, kidney failure, circumcision and a kidney biopsy heighten the risk of bloody urine, states MedlinePlus. Hemophilia, clots in the kidneys and low platelet count also cause blood in the urine.