Fever of unknown origin

This page is for adult patients. For pediatric patients, see: fever of unknown origin (peds)

Differential Diagnosis

• Infectious disease (22%)
  • EBV
  • UTI
  • Enterovirus
  • Lyme
  • Cat-scratch disease
  • Osteomyelitis
  • Psittacosis
  • Rheumatic fever
  • Crohn's
  • Bacterial meningitis
• Autoimmune (6%)
  • JRA
  • SLE
  • PAN
• Malignancy (2%)
  • Leukemia
  • Lymphoma
• Drug-induced fever (2%)
• Factitious (2%)
• No Etiology (67%)

Evaluation

Workup

Phase 1

• CBC
• ESR
• TB test
• MonoSpot
• CXR
• blood culture
• ASLO
• ANA
• HIV

Phase 2

• LP
• blood culture again
• Sinus/mastoid x-ray
• Ophtho exam for iridocyclits
• CMV, Toxo, Hep A/B, Tularemia, Brucellosis, Leptospirosis, Salmonellosis
• LFTs

Phase 3

• Abd ultrasound
• Abd CT
• Gallium/Indium scanning
• UGI series with sbft
• Bone marrow
• Technetium bone scan

See Also

• Fever
• Fever of unknown origin (peds)