Acute fever

Background

Definition

• Defined as temperature ≥38°C (100.4°F)
• >41.0°C (105°F) needs urgent treatment (damage neurons)

Acute Fever Differential Diagnosis

Fever

Infectious

• Critical
  • Sepsis
  • PNA with respiratory failure
  • Peritonitis
  • Meningitis
  • Cavernous Sinus Thrombosis
  • Necrotizing Fasciitis
• Emergent
  • PNA
  • Peritonsillar Abscess
  • Retropharyngeal Abscess
  • Epiglottitis
  • Endocarditis
  • Pericarditis
  • Appendicitis
  • Cholecystitis
  • Diverticulitis
  • Intra-abdominal abscess
  • Pyelonephritis
  • Tubo-ovarian abscess
  • Encephalitis
  • Brain abscess
  • Cellulitis
  • Abscess
  • Malaria
• Non-emergent
  • Viral syndrome
  • Otitis Media
  • Sinusitis
  • Pharyngitis
  • Influenza
  • TB
  • UTI
  • Epididymitis
  • Prostatitis

Non-infectious

• Critical
  • AMI
  • PE
  • Intracranial Hemorrhage
  • CVA
  • NMS
  • Thyroid Storm
  • Acute Adrenal Insufficiency
  • Transfusion Rx
  • Pulmonary Edema
  • Heat Stroke
  • Malignant hyperthermia
• Emergent
  • CHF
  • Dehydration
  • Recent Seizure
  • Sickle Cell Dz
  • Transplant rejection
  • Pancreatitis
  • DVT
  • Serotonin Syndrome
• Non-emergent
  • Drug fever (except as in NMS and Serotonin Syndrome)
  • Malignancy
  • Gout
  • Sarcoidosis
  • Crohn's Disease
  • Postmyocardiotomy syndrome
  • Sweet's syndrome

DDx by Heart Rate

Fever 0.55 C increases HR ~10bts/min

1. Relative bradycardia
   1. Concomitant medication
   2. Drug fever
   3. Typhoid Fever
   4. Brucellosis
   5. Leptospirosis
2. Frank bradycardia
   1. Rheumatic Fever
   2. Lyme Disease
   3. Viral Myocarditis
   4. Endocarditis

Workup

See individual notes for specific workup:

• Fever and Rash
• Fever of Unknown Origin
• Neutropenic Fever
• AIDS Fever of Unknown Origin
• Heat Emergencies
• Fever in Traveler

See Also

• Fever (Peds)
• FUO (Peds)
• Fever and Rash
• Fever of Unknown Origin
• Neutropenic Fever
• AIDS Fever of Unknown Origin
• Heat Emergencies
• Fever in Traveler