Fever


Definitions


Etiology

Infection

Cardiovascular

Dermatologic

Endocrinologic

Gastrointestinal

Neurologic

Ophthalmologic

  • Tularemia (see Tularemia)
    • Oculoglandular Tularemia

Otolaryngologic

  • Acute Rhinosinusitis (see Acute Rhinosinusitis)
    • Epidemiology
      • Uncommon in Adults (Transient Mild Hypothermia May Be Observed Early in the Course in Some Cases) (Arch Intern Med, 1958) [MEDLINE]
      • May Occur in Children
    • Clinical
  • Cervicofacial Actinomycosis (see Actinomycosis)
  • Cytomegalovirus-Associated Infectious Mononucleosis (see Cytomegalovirus)
    • Epidemiology
      • Cytomegalovirus May Cause a Syndrome Which is Clinically Similar, But Typically Milder, than Epstein-Barr Virus-Associated Infectious Mononucleosis (see Epstein-Barr Virus) (Br Med J, 1965) [MEDLINE] (Ann Intern Med, 1973) [MEDLINE]
    • Clinical
      • Fever
        • Occurs in 89% of Cases
        • May Be Prolonged
  • Deep Neck Infection (see Deep Neck Infection)
  • Dental Abscess (see xxxx)
  • Infectious Mononucleosis (Epstein-Barr Virus) (see Epstein-Barr Virus)
  • Pharyngitis (see Pharyngitis)
    • Epidemiology
      • XXXXXXXXX
  • Tularemia (see Tularemia)
    • Pharyngeal/Oropharyngeal Tularemia: pharyngitis

Pulmonary

  • Actinomycosis (see Actinomycosis)
    • XXXXX
  • Complicated Parapneumonic Effusion/Empyema (see Pleural Effusion-Parapneumonic)
    • XXXXX
  • Influenza (see Influenza Virus)
    • Epidemiology
      • Fever is Common
    • Clinical
      • Dry Cough (see Cough)
      • Fever is Generally Between 100-104 Degrees°F
      • Myalgias (see Myalgias)
  • Histoplasmosis (see Histoplasmosis)
  • Influenza (see Influenza)
  • Inhalational Anthrax (Woolsorter’s Disease) (see Anthrax)
    • XXXX
  • Leptospirosis (see Leptospirosis)
    • XXXXX
  • Lung Abscess (see Lung Abscess)
    • XXXX
  • Melioidosis (see Melioidosis)
    • XXXXX
  • Mediastinitis (see Mediastinitis)
  • Nocardiosis (see Nocardiosis)
  • Pertussis (Whooping Cough) (see Pertussis)
    • Clinical
  • Pneumocystis Jirovecii (PJP) (see Pneumocystis Jirovecii)
    • Epidemiology
      • Associated with HIV/AIDS, immunosuppression, etc
  • Pneumonia
  • Psittacosis (see Psittacosis)
  • Q Fever (see Q Fever)
  • SARS-CoV-2 (see xxxx)
    • Epidemiology
      • XXXX
  • Tuberculosis (TB) (see Tuberculosis)
    • Epidemiology
      • Tuberculosis is the Most Common Etiology of Fever of Unknown Origin in Most Studies
  • Tularemia (see Tularemia)
    • Pneumonic Tularemia
      • Pneumonia-Like Presentation
  • VEXAS Syndrome (Vacuoles, E1 Enzyme, X-Linked, Autoinflammatory, Somatic Syndrome) (see VEXAS Syndrome)
    • Epidemiology
      • Median Age: 68 y/o (Range: 57-89 y/o) (Resp Med, 2023) [MEDLINE]
      • All Males (Resp Med, 2023) [MEDLINE]
    • Physiology
      • Most Patients (84% of Cases) Demonstrate Canonical UBA1 Methionine-41 (p.Met41) Somatic Mutations in Hematopoietic Cells (Resp Med, 2023) [MEDLINE]
    • Diagnosis
      • Chest Computed Tomography (CT) (see Chest Computed Tomography)
        • Abnormal in 91% of Cases
        • Parenchymal Opacities (74% of Cases): most commonly ground-glass infiltrates (47% of cases)
        • Mediastinal lymphadenopathy (29% of Cases)
        • Airway Abnormalities (29% of Cases)
        • Pleural Effusion (24% of Cases)
      • Pulmonary Function Tests (PFT’s) (see Pulmonary Function Tests)
        • Pulmonary Function Test Results (Available in 40% of Patients) Demonstrated Normal PFT’s or Mild Restriction (Resp Med, 2023) [MEDLINE]
      • Bronchoscopy with Bronchoalveolar Lavage (BAL) (see Bronchoscopy)
        • Neutrophilic Alveolitis
      • Lung Biopsy (see xxxx)
        • Parenchymal Inflammation
    • Clinical (Resp Med, 2023) [MEDLINE]
      • Fever (82% of Cases)
      • Respiratory Symptoms (93% of Cases)
      • Skin Lesions (91% of Cases)
    • Treatment
      • All Patients Received Glucocorticoid with At Least Partial Response, But Relapses were Common (Requiring Other Immunosuppressives) (Resp Med, 2023) [MEDLINE]
      • Pulmonary Involvement Appeared to Improve with Tocilizumab and JAK Inhibitors (Resp Med, 2023) [MEDLINE]

Renal/Urologic

Reproductive/Pregnancy-Associated

Rheumatologic

Other

Endocrine

Gastrointestinal

Hematologic/Immunologic

Neoplasm

Neurologic

Pulmonary

Renal

Rheumatologic

Vascular

Drugs

Antiarrhythmics

Antibiotics

Antiepileptics

Antihypertensives

Antithyroid Medications

Other

Intoxication

Withdrawal

Other

Fever in the Returning Traveler

Noninfectious Etiologies of Fever in the ICU (Crit Care Med, 2023) [MEDLINE]


Physiology

Definition of Fever

  • Fever is Defined as Morning Temperature >37.2°C (98.9°F) or Afternoon Temperature of >37.7°C (99.9°F)
    • VA Study of Normal Body Temperature (JAMA, 1992) [MEDLINE]: n = 148 healthy men and women (age 18-40 y/o), 700 measurements
      • Oral temperatures in the cohort ranged from 35.6°C (96.0°F) to 38.2°C (100.8°F) with a mean of 36.8 ± 0.4°C (98.2 ± 0.7°F)
      • Low levels occurred at 6 AM and higher levels at 4 to 6 PM
      • The maximum normal oral temperature at 6 AM was 37.2°C (98.9°F), and the maximum level at 4 PM was 37.7°C (99.9°F), both values defining the 99th percentile for healthy subjects
  • Site of Temperature Measurement
    • Rectal temperatures are generally 0.6°C (1.0°F) higher than oral readings
    • Oral readings are lower probably because of mouth breathing, which is particularly important in patients with respiratory infections and rapid breathing
    • Tympanic membrane temperature readings are close to core temperature
  • Sex Differences in Body Temperature
    • Although it is well established that women in the luteal (post-ovulatory) phase have higher body temperature, the amplitude of the circadian rhythm for body temperature is the same as in men (Respir Physiol Neurobiol, 2017) [MEDLINE]

Physiologic Implications of Fever

  • Fever May Potentiate Neurologic Injury


Clinical Manifestations

Neurologic Manifestations

Pulmonary Manifestations

Delayed Weaning from Mechanical Ventilation and Worsened Outcome in Acute Respiratory Distress Syndrome (ARDS) (see Acute Respiratory Distress Syndrome)

Other Manifestations


Treatment

Antipyretics

Acetaminophen (Tylenol) (see Acetaminophen)

Ibuprofen (Motrin) (see Ibuprofen)

Surface Cooling

Intravascular Cooling


References

General

Clinical Manifestations