Hi Dave,
I had similar problems to your wife about a year after being diagnosed Type 2. I didn't get quite as ill as I managed to realise things were going wrong sooner. Anyway, to cut a long story short, I had been misdiagnosed as Type 2 and actually have some other form of diabetes and have been put on insulin - the specialist told me he believes I will become Type 1 eventually i.e. my pancreas is gradually stopping insulin production. At the moment, it sometimes produces enough and sometimes doesn't - when it doesn't, I can very quickly go up into the 20s even without much carb. He told me that about 15 to 20% of Type 2s are misdiagnosed because the condition resembles Type 2 at first and responds to the same treatment for a short while, but while Type 2 progresses gradually over many years, this type of diabetes progresses quickly - usually within 2 years of diagnoses. He also said there are about 20 different forms of diabetes and I might never know exactly what my condition is. I'm not saying your wife has the same diabetes as me, simply that it could be that she has progressed more quickly than Type 2 does into insulin dependance. You need to ask the doctors what they are checking her for - another type of diabetes, an infection or something else. Incidentally, while I was ill with this, I was tested for glandular fever as they said that illness causes havoc with diabetics' BGs - ask them what blood tests they have taken and what the results have been.
I hope your wife feels better soon.
Smidge