Fever

Cardinal Presentations

This post is part of a series called “Cardinal Presentations”, based on Rosen’s Emergency Medicine (8th edition).

Causes of Fever

Causes of Fever

Key Features

  • Morbidity and mortality increase with age and comborbidities
  • Most common sources in elderly: respiratory, genitourinary, skin/soft-tissue
  • Atypical presentations: functional decline, altered mental status

Immediate Evaluation and Management

  • Critical Findings

    • Altered mental status
    • Respiratory distress
    • Hemodynamic instability
  • Critical Interventions

    • Airway management, supplemental O2
    • Cardiac monitoring
    • Fluid resuscitation
    • Empiric antibiotics
    • Cooling measures (T>41.0°C)

Pathophysiology of Fever

Production of endogenous or exogenous pyrogens
Increase temperature set point in hypothalamus
Patient experiences chills when core temperature < set point
Vasoconstriction, shivering causes fever
Patient experiences euthermia, though may feel malaise, fatigue
Resolution
Patient experiences sweats until core temperature returns to normal set point

References

  1. Blum, F., & Biros, M. (2013). Fever in the Adult Patient. In Rosen’s Emergency Medicine – Concepts and Clinical Practice (8th ed., Vol. 1, pp. 119-123). Elsevier Health Sciences.