Fever Source

Fever Source

------------------------------------------------------------------------------
QUESTION: I had a fever recently, which my doctor diagnosed as being caused
by a localized infection. In the course of treating me, he mentioned that it
is impossible to successfully uncover the source of a fever. Is he correct?
------------------------------------------------------------------------------
ANSWER: Unfortunately, your doctor is right. While most fevers are either
temporary or traceable to a specific ailment, there is a group referred to as
FUO--fevers of unknown origin. To be included in this classification, the
fever must be present and have eluded normal attempts at diagnosis for at
least three weeks. The fever may fall into one of four patterns: a)
intermittent; where the temperature returns to a normal level on a daily
basis, b) remittent; the fever remains although the temperature subsides to a
lower level daily, c) a sustained, consistent fever, and d) a relapsing fever
that vanishes for days at a time, only to return.
Most of these fevers can eventually be diagnosed, but only with a
sustained investment of time and effort on the part of the doctor and
increased costs for the patient. The physician first constructs a complete
patient history, emphasizing recent travel, new pets or plants, work
environment, visits to sick friends or relatives, as well as other factors
that can help narrow the range of possible causes. A daily physical exam
paying close attention to subtle details (the base of nails, skin condition,
mucous membranes, the condition of lymph nodes or hidden rashes) is also a
must, together with repeated lab tests on blood, urine or stool samples.
Occasionally, x-ray studies, CT scanning, endoscopies or even biopsies may be
necessary.
In most cases, these procedures will eventually yield definitive answers.
Unfortunately, the majority of these fevers are caused by neoplasms--abnormal
tissue growth--including lymphoma, leukemia and solid tumors. Infections
account for one-third of FUO cases: system-wide infections are most often
traced back to fungal bacteria, while localized infections are generally
centered in the abdomen. A variety of other diseases account for almost all
the remaining fevers, including rheumatic fever, lupus erythematosus,
hepatitis and gout. However, some 10% of these mysterious fevers still defy
diagnosis, in spite of today's advanced medical knowledge and technology.