5. Kidney stones
A kidney stone is a hard, crystalline mineral material formed within the kidney or urinary tract. Kidney stones are a common cause of blood in the urine (hematuria) and often cause severe pain in the pelvic area, abdomen, flank, groin, problems urinating and cloudy, bloody, or foul-smelling urine. Kidney stones are sometimes called renal calculi. It is usually found in the kidneys or in the ureter, the tube that connects the kidneys to your bladder.
They can be extremely painful if they break loose and push into the ureters, the narrow ducts leading to the bladder, and can lead to kidney infections or the kidney not working properly if left untreated. Salts and other minerals in urine stick together with which the small kidney stones are formed. Sizes of kidneys vary from the size of a sugar crystal to a ping pong ball, but they are rarely noticed unless they cause a blockage.