What Causes Fever And Shivering?

Hai my uncle was suffering with fever from last 20 days like shivering & fever .so many doctors consulted and medicine suggested fluconazole & ciprofloxacin & paracetamol used but still same situation.yestrrday once agian consultrd doctor he said urine infection reprts are sugar & bile pigments protiens are negative. pus cells 8-10/hpf ep cells 2-4 / hpf doctor presctibed paracetamol 1000 mg & cefuroaxime 250