I know maybe not right place for it, but a few friends after presenting with severe lower back pain. Docs thinking its kidney infection/uti but test neg but blood in urine and high ketones.
Then think kidney stones, but ct scan neg for those too, but shows inflammation in small gut.
They then diagnose sudden onset crohns/diverticulitis.
Even though a small sample size, of 4 people i know, have all ended up with this. (Young and old alike, no previous)
However there is now suspicion its covid in gut triggering this reaction and so investigating that. (Ace2 receptor in small gut). Pcr nose swabs neg and trying to sort test for stool samples etc.
Anyhow a digression, but if anyone you know presents like this, might be worth mentioning and save weeks of agony and invasive tests or at least rule it out at start.