My son was born with Kidney and bladder issues and as a result has had 4 operations. Since he was born if he get a bug it seems to really take hold of him causing temps over 40!! with no other symptoms at all. its baffling. He is currently the 3rd week in an increasing temp - he started with going up to 37.8 and now he is going up to 39. paracetamol and ibuprofen bring it down but once its worn off its back up again - any ideas?