My son had gastroenteritis with diarrhea vomiting and fever 2 weeks back. Got admitted and treated. His CRP was 200 at the time of admission. His symptoms subsided in a week and got discharged. Antibiotics were not given through IV. only a day before discharge, antibiotics were started orally since he had blood in his stool. We continued the antibiotics at home for 3 days. He got better. On the 4th day night he developed fever. Initially doc said it to be viral and treated only with calpol. Fever lasted for 6 days. We did blood work on 6th day and found CRP to be 42. So started antibiotics again orally. Now 8th h day fever subsided. Was the previous infection not cleared properly and that's y he got second time fever ? Why CRP is so high.