Transcript Fever of Unknown Origin

Fever of Unknown Origin
Definition
Fever > 38.3 on several occasions
 Fever lasting more than 3 weeks
 No diagnosis despite 1 week of
inpatient workup
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Potential Etiologies
Based on patient population
 Classical
 Immunodeficient (Neutropenic)
 Nosocomial
 HIV related
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Classic FUO
Fever > 38.3
 Duration greater than 3 weeks
 Evaluation for 3 weeks as an
outpatient or 3 days in hospital
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Classic FUO
Infection
 Malignancy
 Collagen vascular diseases
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Nosocomial FUO
Fever > 38.3
 Patient hospitalized > 24 hours, but no
fever on admission
 Evaluation for at least 3 days
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Nosocomial FUO
Clostridium difficile
 Drug induced
 Pulmonary embolism
 Septic thrombophlebitis
 Sinusitis
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Neutropenic FUO
Fever > 38.3
 ANC 500 or less
 Evaluation for at least 3 days
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Neutropenic FUO
Opportunistic bacterial infections
 Herpes Virus
 Aspergillosis
 Candidiasis
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HIV FUO
Fever > 38.3
 Duration > 4 weeks (outpatient) or > 3
days (inpatient)
 HIV infection confirmed
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HIV FUO
CMV
 MAC
 PCP
 Drug induced
 Kaposi’s Sarcoma
 Lymphoma
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Infections
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Tuberculosis (especially extrapulmonary)
Abdominal abscesses
Pelvic abscesses
Dental abscesses
Endocarditis
Osteomyelitis
Sinusitis
Cytomegalovirus
Epstein-Barr virus
Human immunodeficiency virus
Lyme disease
Prostatitis
Sinusitis
Infections
As duration of fever increases,
infectious etiology decreases
 Malignancy and factitious fevers are
more common in patients with
prolonged FUO.
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Malignancies
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Chronic leukemia
Lymphoma
Metastatic cancers
Renal cell carcinoma
Colon carcinoma
Hepatoma
Myelodysplastic syndromes
Pancreatic carcinoma
Sarcomas
Autoimmune
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Adult Still's disease
Polymyalgia rheumatica
Temporal arteritis
Rheumatoid arthritis
Rheumatoid fever
Inflammatory bowel disease
Reiter's syndrome
Systemic lupus erythematosus
Vasculitides
Miscellaneous
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Drug-induced fever
Complications from cirrhosis
Factitious fever
Hepatitis (alcoholic, granulomatous, or
lupoid)
Deep venous thrombosis
Sarcoidosis
Diagnosis
Failure to reach a diagnosis is not
uncommon
 20% of cases remain undiagnosed
 Even if extensive investigation does not
identify a cause, these patient’s still
have favorable outcomes.
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Diagnosis
Comprehensive History
 Physical Exam
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Confirm fever and document pattern
Laboratory Data
History
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Recent travel
Exposure to pets and other animals
Sexual history
Work environment
Contact with other people with similar
symptoms
Family history
Past medical history list of medications
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Include OTC
Physical Exam
Skin
 Mucus membranes
 Lymphadenopathy
 Organomegaly
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Diagnosis
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A cost-effective individualized
approach is essential in the evaluation
of these patients to prevent
performing inappropriate tests.
Diagnosis of Fever of Unknown Origin
Diagnostic Testing
CBC
 LFTs
 ESR
 Urinalysis
 Blood cultures
 Further testing should be based on
abnormalities in the initial workup
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Diagnosis
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PPD testing is inexpensive screening
tool that should be used on all FUO
patients that do not have a known
positive reaction
Diagnosis
If initial testing is inconclusive- more
specific testing should be performed
based on clinical suspicion
 Serologies
 CT
 Ultrasounds
 MRI
 Nuclear Medicine Scans
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Chest radiograph
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CT of abdomen or pelvis with contrast agent
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Malignancy, inflammation
Transthoracic or transesophageal echocardiography
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Malignancy, autoimmune conditions
PET scan
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Acute infection and inflammation of bones and soft tissue
MRI of brain
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Occult septicemia
Technetium Tc 99m
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Infection, malignancy
Indium-labeled leukocytes
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Abscess, malignancy
Gallium 67 scan
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Tuberculosis, malignancy, Pneumocystis carinii pneumonia
Bacterial endocarditis
Venous Doppler study
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Venous thrombosis
Diagnosis
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More invasive testing, such as LP or biopsy of
bone marrow, liver, or lymph nodes, should be
performed only when clinical suspicion shows
that these tests are indicated or when the
source of the fever remains unidentified
after extensive evaluation.
When the definitive diagnosis remains elusive
and the complexity of the case increases, an
infectious disease, rheumatology, or oncology
consultation may be helpful.