If you are one of my fellow cystinuria friends you probably guessed it after reading the title. If not and you're still struggling with the answer here is a picture of it.
Yes, if you haven't guessed already it is a kidney stone. And although small and insignificant by size can cause a hell of a lot of pain and grief. Basically, they grow in the kidney through a process of crystallisation. Occasionally they fall out and cause a blockage arresting the natural flow of urine from the kidney to the bladder. This causes pressure in the kidney which leads to excruciating pain.
Eventually the stone passes into the bladder and then out into the open air during urination. A question I get a lot is does that hurt. Really, not nearly as much as when it blocks the kidney, if at all. But the pain whilst the stone blocks the kidney is debilitating. It can stop you dead in your tracks. I have felt really quite productive this year too. But a kidney stone will put a stop to that. After I dosed myself up on pain killers I felt capable of nothing accept keeping my spot on the couch warm.
I think I have been lucky though. Ever since my kidney op in April I have been passing a small stone every two to three weeks which is probably just residuals from the procedure but they have not caused me any problems. I guess my luck just ran out. The important thing is that I'm all better now. Stay well:)