Tasty Morsels of EM 041 – Acute Urinary Retention

7 Jul

[Featured Image: Frivadossi, Wikimedia Commons]

As always, this is from the ever expanding google doc on bits and bobs I read and learn from.

This time:

ED Management of acute urinary retention. EB Medicine

  • Causes
    • Men – think prostate
    • Women – bladder masses, gynae surgery and prolapse
    • Drugs: calcium channel blockers (i didn’t know this), anticholergics (i did know this one)
    • Spinal cord compression is probably the real emergent cause we need to think of
    • In a similar manner to other neuropathies, diabetics can get a diabetic cystopathy resulting in AUR.
  • The big take home should be this: you need to bloody well examine them. There is a real (and justifiable) desire to just slip in the catheter (or worse get someone else to do it) and get disposal nice and quickly. But as simple as most AUR is, you will miss important things (say spinal cord compression, or a penile tumour, especially in the patient with dementia or non-verbal patients) if you don’t physically get involved with the gorey details.
  • there’s some ‘himming’ and ‘haaing’ over whether to put a finger in the rectum. The main concern seems to be in prostatitis and seeding the blood with a prostate exam. They’re right to say that there’s no evidence of this causing harm. But that works both ways – there’s no evidence either way. There’s not a great deal of diagnostic value here I don’t think. The bigger issue is whether to put a catheter through an infected prostate. I figure if they’re in retention then I do it, and they get a nice chaser of gentamicin and an admission.
  • there’s some interesting stuff on urine samples for prostatitis. You can collect wee at lots of different points of the wee cycle and then massage the prostate a bit and get another few mls. There’s even a study looking at semen cultures for prostatitis. I imagine if I had prostatitis the last thing I might be able to do is provide a semen sample…
  • getting the patient to exhale when the tip is at the prostate seems to be of some use in relaxing the relevant sphincters
  • an episode of hypotension following bladder decompression is common due to a reflex response in reduced vascular resistance. Doesn’t mean the you don’t have to think about whether that patient’s severe abdo pain was actually a AAA rather than AUR…
  • they (sensibly) state that if it’s a simple catheter and no reason to think infection then antibiotics are not indicated. Very different from the raging, septic prostatitis
  • they quote the common figure of 2 in 3 patients requiring repeat catheterisation if the catheter is immediately pulled. They also note that those with a spontaneous AUR (which is likely prostatic hypertrophy in origin) is more likely to need a second catheter than those with a precipitated cause (eg infection or constipation).
  • they suggest that the 2 in 3 rate of recurrence mandates that the catheter is left in whereas I think that “hey, I have a 1 in 3 chance of not needing this – i’ll take those odds and come back if I can’t pee again”
  • catheters that get stuck and can’t be removed are usually due a ridge forming on the balloon during deflation and can be dealt with very slow reinflation and deinflation. The inflation channel can also be cut. Interestingly they say that filling the balloon with 10mls of mineral oil will dissolve the balloon in about 15 mins and allow removal. I have no idea if this applies to all makes.

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