Case 044: the answer

Ok, 24 hours in and we have a winner.  The most comprehensive and correct / first in (20 minutes) answer was from Egerton Yorrick Davis IV (I wonder what happened to the first 3 EYDs?)  His answer went right to the red heart of the problem and picked up the diagnostic pitfalls en route.  Here it is:

“Most 40y old women will have gallstones – it is easy to get entrapped by this diagnosis as a cause of epigastric pain.
Dyspepsia + anemia = upper GI bleed until proven otherwise – but penicious anemia or gastritis with parietal cell depletion and intrinsic factor deficiency leading to VitB12 is in the DDX.
Depression is also common – but can be a feature of anemia, or even B12 deficiency.
When she has her op she may have got nitrous oxide as part of her anesthetic – which could exacerbate B12 deficiency – and was probably fasted +/- eating a low B12 diet (meat, eggs, milk)
Neurological symptoms (including paraestheiae) are the other component of the triad for B12 deficiency.

If you want to see more on Subacute Combined cord degeneration – check out this link(Neurology, Neurosurgery and Psychiarty 1998) which was sent in by Minh Le Cong as part of his answer (too slow sorry Minh).

Great answers though, thanks for the input.  Casey


  1. toby thomas says

    Too clever for me. It’s been a long time since I was in theatres but isn’t nitrous oxide avoided in Lap chole’s as it can accumulates in the pneumoperitoneum and its flammable? (ie can go boom)

  2. Casey Parker says

    Hi Toby
    N2O is not contraindicated for laparoscopic work, but true – it is not often used – mainly as it is vomit-inducing. It is not flammable though.
    It is avoided in surgery with entrapped air spaces or where small air flow can be problematic – especially ENT ear surgery

    • toby thomas says

      I had a vague memory of a paper by some french guys who did laprascopic surgery of pigs, introduced Nitrous oxide into the breathing cirucuit and they exploded. (mmm, bacon) But as is so often the case I was wrong. What they actually found was that during prolonged laparoscopy, nitorous oxide can diffuse into the peritoneum and mix with carbon dioxide reaching levels of 29% or above which they state “may be sufficient to support combustion” with sparking from the cautery device.

      As much as I like pigs, I prefer my version.

      Nitrous Oxide Fraction in the Carbon Dioxide Pneumoperitoneum During Laparoscopy Under General Inhaled Anesthesia in Pigs

  3. minh le cong says

    are you, Tim, Jonathan or anyone still using nitrous during GAs?

  4. Michael Toolis says

    Wow that is slick.

  5. Minh asks re: nitrous oxide

    Yeah, I’ll admit to a guilty little secret – I like nitrous oxide! Great for kids, dental, labour. And I will do a few simple cases on it.

    ENIGMA had some methodological flaws (not least different FiO2s between groups). If I recall, the main outcome measure was duration of hospital stay – and no difference between N2O and non-N2O.

    I await ENIGMA II with interest.

    But I am a medical dinosaur.

    • Minh Le Cong says

      I agree Tim. Nitrous is great for procedures in the ED. Last night I lost count of the number of plasters I put on kids using nitrous !

      My question is more about whether rural GPAs are still using nitrous in theatre for GAs…since ENIGMA.

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