But in Type 1's I thought that ketoacidosis requires high ketones and very high blood sugars (no insulin)?
Not necessarily. There's a rare version called euglycaemic dka which can occur without high bg if a few bad things happen at the wrong times.
Can't find the link now, but there was a quite disturbing post a few weeks back when a T1 posted describing symptoms which chimed a lot with the symptoms and causes described in the link below - chills, nausea, fasting, lots of water, still taking basal.
She was worried about high ketones, but had ok bg.
She was, irresponsibly in my view, and despite others, including me, telling her to see emergency services immediately, reassured by a keto person, that because she didn't have high bg, she didn't have to worry about dka at all, even though the other symptoms she posted about went way beyond keto flu and seemed to suggest that euglycaemic dka might be a possibility.
Nutritional ketosis is an option for experienced people but, hmm, not so simple for T1 newbies.
Here's the link referred to above:
www.ncbi.nlm.nih.gov/pmc/articles/PMC4488998/