Hello! I read your concerns and will try to break it down all your problems systematically. Fever is commonly caused by an infection, the antibiotics (
ciprofloxacin) he took may be not sensitive to the infection he presently has, that is why his symptoms persisted. Aversion to food is common in patients who are ill, in your husband's case, it could narrow down the where the cause of his infection is coming from-- gut, kidneys, and liver. The lower back pain in your husband's case is one of the clues where his infection is coming from-- kidneys, bladder, pancreas, liver. The dark urine could be due to
dehydration, since he is not taking anything orally.
If I was your treating physician, I will request the following--
complete blood count,
urinalysis,
blood culture, kidney and liver function tests, a whole abdomen ultrasound or CT scan. I also suggest he gets admitted during all these test in order for him to get hydrated intravenously with fluids. Once he gets all the results, he could get treated right away. I hope he gets well soon! Have a nice day!