Table 2.

Fever patterns

Prolonged fever• Single episode in which duration of fever is longer than expected for the clinical diagnosis (eg, viral syndrome lasting > 10 d)
• Single episode in which fever was initially a prominent feature but then becomes low grade or only a perceived problem
Fever of unknown origin• Single episode lasting > 3 wk during which fever is > 38.3°C on most days; diagnosis remains uncertain after 1 wk of intense evaluation
Recurrent fever• Single episode during which signs (including fever) and symptoms wax and wane
• Repeated unrelated febrile episodes involving a single organ system (eg, sinopulmonary, urinary tract)
• Repeated febrile episodes occurring at irregular intervals involving different organ systems in which fever is one variable component
Periodic fever• Recurring episodes (with either strict periodicity or irregular intervals) lasting days to weeks in which fever is the cardinal feature and other associated features are similar and predictable; intervening intervals of weeks to months characterized by complete well-being
  • Adapted from Long.3