Cystitis is characterised by inflammation of the bladder, usually caused due to an infection and is more common to women. Symptoms A burning sensation when passing urine and thus the patient tries to avoid passing urine.Urine may become thick and dark and may contain blood and pus in the advanced stages. Root causes May result from infection in other parts of the body that are closer to the bladder such as the kidney. This condition may also arise from acute constipation.