• Chart of the day: The other fever swamp

    A surprisingly large and growing proportion of fevers have no identifiable source, as illustrated in this chart from a new NEJM Perspective on fevers of unknown origin (FUOs), by Harold Horowitz:


    As the keeper of the antibiotics, should I be a conservative or a cowboy? Should the current antibiotics be continued, changed, or stopped? If there are no prescribed antibiotics, should I recommend some? These are interesting questions in the abstract, but there is a real patient suffering, a family with questions, and medical teams awaiting my opinion. There are no evidence-based studies and there is no guidance on which potential source of fever is the single appropriate one to treat. Frequently, the treatment approach is like playing Whac-A-Mole: positive cultures are treated sequentially — pneumonia, then catheter cultures, then urine cultures. When the fever persists, the cycle begins again.

    I have it on good authority that this is what it is really like to practice medicine. Very few patients comprehend just how much uncertainty exists about many treatments and maladies, though not all of them.


    • It’s probably worth noting explicitly that the patients included in the figure are those in whom no obvious source for fever has been found (hence the term ‘fever of unknown origin’). So it’s perhaps fairer to say that among patients in whom no obvious source of fever has been found, a growing proportion end up receiving no specific diagnosis. One reason for this could be better up front diagnostic testing.

      The patients that Dr. Horowitz writes about are primarily being cared for in intensive care units. It is certainly not the case in primary care or internal medicine that 50% of patients with fever end up having no diagnosis.

    • After reading Dr. Horowitz’s article, I thought he was simply trying to explain that modern day typical FUO case is no longer “the multidimensional great case that FUOs were once advertised to be –the cases presented on chief-of-service rounds —-“. He went on to suggest that many of the FUOs are actually Fever of Too Many Origins.
      Dr. Horowitz also mentioned that improved serologic and imaging technologies have something to do with the changing causes of FUOs. So the increasing percentage of fever with no diagnosis is probably not that surprising. It’s just that the pattern is changing.

    • Has any checked to see if this fever is caused by the need for more cowbell? And if more cowbell actually does anything to cool this burning fever?