"Extremely disappointing"

My wife took my 16 month old son to the A&E when he walking with a limp. He was given some paracetamol and ibuprofen because they suspected it could be a strain in his knee. A couple of days later my little one had a sore knee and couldn't stand on his left leg at all. He went back to crawling but this time round he was dragging his left leg behind him while crawling. I realised the medication we were given earlier wasn't working so I took him back to the hospital again. I became very annoyed when a doctor asked me how I know it's my son's knee that was hurting (eventhough his knee was so sore). Anyway an x-ray was done on the whole leg from hip down and nothing at all showed. The doctor asked me to still continue giving him paracetamol and it will get better. I'm no medical expet but I knew they were missing a blood test as there was nothing at all showing. Couple of days later, I drove all the way into London to St Thomas Hospital where my son was born. Another x-ray was done and a blood test was carried out straight away. The blood test showed that he had an infection. They put him on antibiotics straight away and have scheduled an MRI scan. I wonder what would have happend to my son if I had just given him paracetamol in the hope that he will start getting better eventually. For me that's it with Darent Valley!