@SAP
What you say about constipation and urinary retention is not commonly known, but does certainly happen. Before it happened to me, I had no idea such a thing could happen.
I was in hospital for several days on various meds and was not allowed out of bed. This meant having to pee in a urinal and poo in a bedpan, which is not easy as many have found out. Anyway after a few days of not pooing, I woke up in the middle of the night needing to pee urgently. But after trying for a while, without result, the urgency became almost painful so I rang for the nurse and explained the issue. After a couple of questions, she got a ladder scanner and found I was very full.
In a few minutes she returned with a Foley kit and soon I had a Fr 16 latex Foley in me and was thankfully draining into a bedside pee bag. soon thereafter I drifted back to sleep.
During the morning rounds, I discussed the issue with my doctor and she ordered a large volume enema. Soon, the nurse came in with a disposable bag kit, filled it with warm water and added the soap packet, and hung the bag on the IV hook, and gave me the whole bag, and had me roll onto the bedpan. The enema soon worked and I had a large poo into the bedpan.
I was scheduled to be discharged later that day and about an hour before the appointed time another nurse came in with some supplies, including new, disposable leg bags and bed bags. She said the doctor wanted me cathed for about a week and disconnected the bed bag and hooked me up with a leg bag.
About a week later I went to the urology nurse who disconnected the bag, injected three 60ml syringe fulls of saline, and then removed the catheter. She then sent me to the toilet to demonstrate I could pee and after I did, she bladder scanned me to measure the retained pee. She was satisfied and i left.
In short, constipation can surly make one unable to pee.