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