palpable bladders

[auden]

how much urine has to be in a bladder to be palpable per abdomen? I know it will depend on the size of the patient to some extent but does anyone know roughly how much in someone of normal BMI?

[M Clayton]

As you say, it depends very much on the individual patient but I've found that most of the guys I've catheterised because their bladder was palpable have had more than 500mls residual.

500mls also rings distant bells from the little urology teaching I had as a student.

[Rich' Trash]

I thought the internal sphincter wouldn't even open until 400ml.. I guess I've been misinformed?

[M Clayton]

I'm sure it's half that... 200 to 250mls should provoke the urge to urinate and require active thought to prevent it.

EDIT:

Smith's General Urology states that the normal bladder can expand to 400 mls and will only be palpable if moderately distended. Therefore, 500 mls would seem to be about right, no?

[Touche]

500mls is what I was told by a urology reg many moons ago.

I've always had 500mls+ out of any palpable bladder I've catheterised.

I got only 200mls out of a young chap in post op retention once. He had been unable to go despite having the urge for a couple of hours, nothing palpable but he was in discomfort and starting to panic... nothing like a tube up your willy to stop you panicing!

3.5L is my personal record! Poor chap had been treated at home for constipation for 3 days before presenting to A&E

[Rich' Trash]

Originally Posted by Touche

3.5L is my personal record! Poor chap had been treated at home for constipation for 3 days before presenting to A&E

Waw thats a hell of alot.. at least it was an easily fixed problem (?).

The same person that informed by previous comment also told me that a stretched bladder could only hold 1L. Pfft, seems CT surgeons know very little about urology.

[Touche]

Kind of, the catheter was the easy bit!

You often get venous bleeding into the bladder after explosive relief of an obstruction, which happened in his case. So he needed continuous bladder irrigation.

He also had post obstruction diuresis and dropped his BP which was fun.

He had BPH and probably had a chronically dilated bladder. I wouldn't be suprised if his normal residual was around 700ml-1L.

I once worked with a colleague (ex-barmaid) in A&E who would play a 'how much can your bladder hold' game. She would drink loads through a night shift and try to get as high a bladder scan reading as possible. I think she was hitting 1L and she didn't even look in pain!

I'm sure my untrained, non-distended bladder would pop well before 1.5L though.