A kidney stone moves from the kidney, down a ureter, through the bladder, down the urethra and out.
The stone moves in and by the flow of urine.
The ureters and urethra are fibrous muscular tubes that have a rolling squeezing motion that moves urine down those tubes.
Most stones have sharp edges and are pointy.
The edges and points catch against and into the sides of a ureter and the urethra.
When the stone is caught up in one of these tubes your employee experiences a blocked urine flow and feels the need to frequently visit the loo.
Imagine the stone ripping itself free in the urine flow and then being caught again after travelling less than a millimetre down a tube.
Your employee is now experiencing severe pain. The bodies mechanism for severe pain is to pass out. (A heart attack has the same effect)
Now your employee has internal bleeding which is being washed in urine!
Very often your employee will go for hours and days without a stone movement because it is firmly wedged.
Then your employee will move, it can be a different movement or quite normal like standing or reaching and wham they have passed out; in the work place, or when driving or at home.
The treatment is to drink plenty of water and that means having a loo close by. Analgesics to kill the pain are available but no one should be taking them all the time in case of addiction or becoming immune. Antibiotics are also taken but immunity again could become a problem.
Sometimes it takes weeks and months for sufferers to completely pass a kidney stone.
Your employee will probably get very painful kidney infections and/or bladder infections and may go on to have even more stones and risk kidney damage or kidney loss with each stone?
Please remember your employee will have no visible symptoms just an understandable reluctance to move and never be far from a loo.