Fever Lethality Thresholds

High-Risk Populations

Neurologic injury patients, such as those with stroke or intracerebral hemorrhage, face increased mortality risk at lower fever thresholds, where even a 1°F elevation above 99.6°F is an independent predictor of poor outcomes and increased mortality 1, 2
Critically ill ICU patients have increased mortality associated with fever >38.3°C (101°F), though the absence of fever in infected patients paradoxically heralds worse prognosis 3
Elderly patients and those with end-stage organ disease may have blunted fever responses but worse outcomes when fever does occur, according to the American College of Critical Care Medicine 3

The American College of Critical Care Medicine suggests that temperatures <40°C (104°F) should prompt investigation of the source, treatment of the underlying cause, and consideration of antipyretics for patient comfort, although this specific guideline is not provided, a similar guideline is provided by the Infectious Diseases Society of America 5