Fever of Unknown Origin Domenick Roma 7/31/2009

Types Classic FUO Nosocomial FUO Immune-deficient FUO HIV-related FUO

Definition Fever higher than 38.3ºC on several occasions Duration of fever for at least three weeks Uncertain diagnosis after one week of study in the hospital Uncertain diagnosis after 3 outpatient visits or three days of study in the hospital.

History

Physical Exam Facial/Sinus Tenderness  Sinusitis Temporal Artery Tenderness Temporal Arteritis Tenderness of a Tooth  Periapical Dental Abscess Roth Spots on Fundoscopic Exam Endocarditis Enlarged Tender Thyroid  Thyroiditis Murmur  Endocarditis Perirectal Tenderness/Fluctuance  Perirectal Abscess Prostatic Tenderness  Prostatitis or Prostate Abscess Splenomegaly  Lymphoma, Endocarditis, Leishmaniasis Lymphadenopathy  Lymphoma, HIV, Tuberculosis Calf Tenderness  DVT

Approach to Diagnosis Erythrocyte sedimentation rate (and/or C-reactive protein) Antinuclear antibodies Rheumatoid factor Angiotensin-converting enzyme Cytomegalovirus IgM antibodies or virus detection in blood Heterophile antibody test in children and young adults Mantoux skin test CT scan of abdomen (or radionuclide scan) HIV antibody test Comprehensive History Physical Examination Complete blood count, including differential and platelet count Blood cultures (three sets drawn without administering antibiotics) Routine blood chemistries, including liver enzymes and bilirubin Hepatitis serologies (if liver tests abnormal) Urinalysis, including microscopic examination, and urine culture Chest radiograph

Invasive Testing Liver Biopsy Lymph Node Biopsy Bone Marrow Biopsy/Culture Temporal Artery Biopsy Exploratory Laparotomy

Causes

Causes Infectious (16%) Malignancies (7%) TB, Abscess, Endocarditits, Osteomyelitis, Dental Abscess Malignancies (7%) Lymphoma, Leukemia, Renal Cell Carcinoma, Liver (HCC or metastases) Connective Tissue Disease (22%) Adult Stills Disease, Temporal Arteritis, polyarteritis nodosa, Takayasu's arteritis, Wegener's, mixed cryoglobulinemia Other (4%) DVT, Drugs, Factitious, Hypothalmic Dysfunction, Hereditary Fever Syndromes Undiagnosed (51%)

Treatment & Prognosis Treatment Prognosis Empiric antibiotics? Trial of Steroids? Prognosis Depends on final diagnosis Undiagnosed generally have good prognosis

References Clinical Medicine 2008 Oct 8 (5): 526-530. Arch Intern Med. 2003 Mar 10;163(5):545-51. Am Fam Physician. 2003 Dec 1;68(11):2223-8. Up-to-Date