When an infection develops inside the urinary tract. It involves organs like kidney and bladder. It usually occurs due to the invasion of bacteria in these organs.

The usual symptoms are several burning and a feeling that you are pissing razor blades. A high grade fever is also common though it might not develop until much later stage of the infection. The urine may become cloudy and the frequency may also increase.

They are now very easy to diagnose and cure. Just consult a urologist. He will prescribe some tests and then antibiotics will usually clear the body in 3 - 4 days.