When blood in the urine is accompanied by pain in the side, the cause may a urinary tract infection, according to Mayo Clinic. Urinary tract infections impact the kidneys, urethra, bladder and ureters. Symptoms include a strong urge to urinate frequently, a burning sensation when urinating, pelvic pain and a strong odor from urine. When kidneys are impacted by the infection, symptoms can also include fever, shaking, chills, nausea and vomiting.
Urinary tract infections usually occur in the bladder as bacteria invades and multiplies there, explains Mayo Clinic. Infection in the bladder, or cystitis, is usually caused by E. coli, which is commonly found in the gastrointestinal tract. Women are more prone to cystitis due their anatomy and the proximity of the anus to the urethral opening. Infection of the urethra occurs when bacteria is spread from the anus or through sexually transmitted infections, including herpes, chlamydia and gonorrhea.
Many common causes of bloody urine are associated with the kidneys, including kidney stones, infections, kidney disease, tumors or injuries, according to WebMD. Blood in the urine, also known as hematuria, appears as a pink, reddish-brown, tea-color or red discoloration. It is generally not considered an urgent situation requiring treatment; however, it can be related to an underlying condition and should be diagnosed by a medical professional.