Bacterial endocarditis, as you likely know, is a bacterial infection of the lining of the heart, occurring either on the heart valve or somewhere within the heart. This typically occurs at a location in which there is turbulent blood flow, such as in aortic valve stenosis like your son has. Recurrent fevers, often referred to as fever of unknown origin when it lasts past a certain set amount of time and meets certain criteria, can have a long list of possible etiologies, including bacterial endocarditis. The diagnosis of endocarditis is usually made after there is evidence of an infection, such as with a positive blood culture. Usually, these are positive when there is gross evidence of endocarditis. However, there are times when the bacteria are difficult to grow and can cause a smoldering infection with slowly progressive damage. In these cases, a large volume blood culture kept for two weeks is one of the ways that these more difficuilt to grow bacteria can be identified. Also, evidence of inflammation, such as a positive erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) as well as a rheumatoid factor can be nonspecific but helpful markers pointing to endocarditis. Looking for evidence of blood or immune complexes in the urine is also important. If none of these are positive, an echocardiogram has not been demonstrated to be helpful in these cases, and ends up frequently being negative. Obviously, without reviewing all of your son’s information and his examination, I cannot say what his specific risk for endocarditis is at this point.
As an aside, since your son is only 2 years old, a transthoracic echo, if it were needed, should be more than adequate to demonstrate evidence of endocarditis; this means that a transesophageal echo should not be necessary.
Thanks very much for all the information.His inflammation markers are only up when he has a fever,which they also said could lead to a number of things.he has had many blood cultures but as I said all negative.Maybe I should ask for one to be kept for 2 weeks as you said and then see if anything grows.My son has really been through a lot since he was a baby and If I can try and prevent any thing more major happening to him I would love to.Thank you again for all your help.I know for a 2 year old the norm for viruses is 8-10 in a year.well if you call his viruses then he has had 8 since June.we are going to look again at infectious disease and see if they can do anything else.I think as a mom you want to help your child as much as you can.I think we will see if they can do another echo for him.
Thanks again for your time.