If the bladder becomes infected by bacteria (cystitis) the patient will have a fever, feel pain low down in the front of the belly, will pass urine more frequently, and pain will be felt when passing urine. In severe cases the urine will be cloudy and sometimes blood will be seen in the urine.
Pyelonephritis is an infection of a kidney that causes aching pain in a loin, fever, general feeling of being unwell, and sometimes frequent uncomfortable passing of urine.
Prostatitis is a bacterial infection of the prostate gland at the base of the penis. Symptoms include difficulty in passing urine, dysuria, pelvic and penis discomfort and pain, and sometimes a fever.
Pelvic inflammatory disease is a widespread infection of the organs and tissues within a woman’s pelvis, often caused by sexually transmitted diseases. Pain occurs with passing urine as the infected tissue moves as the bladder size suddenly shrinks.
Reiter syndrome causes conjunctivitis, inflammation of the urethra, arthritis and painful ulceration of the gums. Its cause is unknown, but settles slowly without treatment, although recurrences are possible.
A prolapse (bulging) of the bladder into the front wall of the vagina in a woman will make passing urine difficult and uncomfortable, and increases the risk of infection.