high fevers in child(FUO)

  My friends son (age 13)has been having unexplained high fevers for several months now.  This fever goes as high as 105 and goes and comes. He has had many tests and they cant find out what is causing it.  He doesnt have many other symptoms except frequent headaches, and malaise.  He had a brain mri without  dye that they said was normal. My question is - could there be any neurological cause of this fever? ie brain disfuncion? -- These fevers are strange in that he doesnt get hot and red and miserable as one usually would with a fever that high. His family is very frustrated at this point. They are thinking of taking him out of state to a specialty clinic.  Thank you  for any info or insight you may be able to offer!!
Dear Robert,
I am sorry to hear about your friend's son's high fevers.  Since they have been for several months now they do fit the criteria for FUO.  Does the fever come and go at any constant time of the day?  Does the fever respond to medications at all?  Has there been any rashes or other abnormal findings since the fevers began or preceding the fevers at any time?  There are several areas that can cause high fevers.  The most common cause of FUOs are infections.  After that the usual causes are collagen-vascular diseases, malignancy, endocrine, drugs (medications), or metabolic disorders.  All these are likely being worked up currently.  I must add that of all the FUO that I have seen the last few years, all but two have been due to infections.  The other two were a malignancy and collagen-vascular.  You ask about CNS causes of high fevers.  Yes, it can happen but these are exceedingly rare.  They are usual in the malignancy category and involve the hypothalmus.  These are usually found by MRI and since your friend's son's MRI was normal it does seem to be this enity.  Good luck in the workup.  I hope they find a benign etiolgoy.
Sincerely,
CCF Neuro:Pediatrics MD, RPS