Download FUO 3

Definition
 Fever higher than 38.3 Celsius on several occasions
 Duration of fever for at least three weeks
 Uncertain diagnosis after one week in the hospital
Definition
 Unremarkable
 History/physical
 CBC w/ diff
 Blood cultures
 Chemistries with LFTs

Hepatitis serology if appropriate
 UA/Urine culture
 Chest film
Etiology
 Connective tissue diseases
 22 percent
 Infections
 16 percent
 Malignancies
 7 percent
 Miscellaneous (drugs, clot, factitious)
 4 percent
 No diagnosis
 51 percent
Infections
 Tuberculosis
 Especially in immunodeficiency

Normal CXR 15-30% of cases
 Abscess
 Usually in abdomen or pelvis
 Predisposed by diabetes, recent surgery, steroid tx
 Osteomyelitis
 In cases with nonlocalized symptoms consider
vertebral or mandibular osteo
Infections
 Bacterial Endocarditis/abscess
 Culture negative cases
 Coxilla burnetti (Q fever),
Tropheryma whipplei, Brucella,
Mycoplasma, chlamydia,
histoplasma, legionella, bartonella
 HACEK organisms

Haemophilus, actinobacillus,
cardiobacterium, eikenella, and
kingella take 1 to 3 weeks to grow
Connective Tissue Diseases
 Adult Still’s Disease
 Daily fevers, arthritis, and evanescent rash
 Giant Cell Arteritis
 Headache, vision loss, arthritis

Jaw claudication
 Polyarteritis nodosa
 Takayasu’s arteritis
 Wegner’s granulomatosis
 Cryoglobulinemia
Malignancy
 Leukemia/lymphomas
 Typically determined by bone marrow biopsy or CT/MRI
imaging
 Myelodysplastic syndrome
 With dysplastic changes in blood line
 Multiple myeloma
Malignancy
 Renal cell carcinomas
 Present with fever 20% of cases
 Hepatitic metastases
 Required for most other adenocarcinomas to cause fever
 Atrial myxomas
 Present with fever 1/3 of cases
 Also with arthralgias, emboli, hypergammaglobulinemia
Drugs
 “Drug fever”
 Eosinophilia and rash in only 25% of cases
 Antibiotics

Sulfa, PCN, Vancomycin, Antimalarials
 Antihistamines

H1 and H2 blockers
 Antiepileptics

Barbiturates and phenytoin
Drugs
 NSAIDs
 Antihypertensives

Hydralazine, methyldopa
 Antiarrythmics

Quinidine, procainamide
 Stop for 72 hours and monitor for
improvement/defervescene
Factitious Fever
 Underlying psychiatric condition
 Typically in women and healthcare professionals
 Besides manipulation of thermometers fever can be
induced by
 Taking meds which pt is allergic to
 Injecting foreign matter parenterally

Milk, urine, culture media, feces
Other
 Disordered heat homeostasis
 Follows hypothalamic dysfunction typically after massive CVA
or anoxic brain injury
 Hyperthyroidism
 Dental abscess
 Less common infections
 Pulmonary

Q fever, leptospirosis, psittacosis, tularemia
 Nonpulmonary
 Syphillis, disseminated gonococcemia, Whipple’s disease, RMSF
 Alcoholic hepatitis
 Fever, hepatomegaly, jaundice
Other
 Pulmonary embolism/DVT
 Hematoma
 Hip, pelvis, retroperitoneum
 Pheochromocytoma
 Adrenal insufficiency
 Familial Mediterranean fever
Diagnosis
 History and physical with focus on
 Travel
 Animal contacts
 Immunosuppression
 Drug history
 Localizing symptoms
Laboratory Work-up
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Chem-10
CBC w/ differential
ESR or CRP
TB skin test
HIV antibody
Rheumatoid factor
CK
ANA
SPEP
Blood cultures x 3 separated by space and time off
antibiotics
Imaging
 Recommend if appropriate
 CXR
 CT Abdomen/Pelvis or Chest


Replaced exploratory laparotomy
Helpful in localized abscess, LAD
 Not recommended unless otherwise indicated
 Bone scan
Biopsy
 Bone marrow biopsy
 Malignancy, TB
 Liver biopsy
 Sarcoidosis, TB
 Lymph node biopsy
 Lymphoma, infection
 Temporal artery biopsy
 Giant cell arteritis
Therapy
 Empiric antibiotics are not recommended given
 Possible suppression without cure

Abdominal abscess
 Unknown length of treatment
 Endocarditis
 Steroids also may be consider
 However must be relatively certain no infection present
 Must be certain not to interfere with inflammatory
workup
 Steroids or antibiotics empirically rarely aid in
diagnosis and risk harm to patient
Outcome
 Many FUOs end up with no definitive diagnosis
 About 50% of people without diagnosis improve
within hospitalization or soon thereafter
 15% have persistent fever that lasts at least 1 year
 Rarely does death develop from FUOs
References
 Bleeker-Rovers, CP, et al. A prospective multicenter study
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on fever of unknown origin: the yield of a structured
diagnostic protocol. Medicine (Baltimore) 2007; 86:26.
Petersdorf, RG. Fever of unknown origin: An old friend
revisited. Arch Intern Med 1992; 152:21.
Hirshmann, JV. Fever of unknown origin in adults. Clin
Infect Dis 1997; 24: 291.
Vandershueren, S, et al. From prolonged febrile illness to
Fever of unknown origin: the challenge continues. Arch
Intern Med 2003; 163: 1033.
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