Fever of Unknown Origin

Question 1

What is the definition of FUO?

Answer 1

-First developed in 1961 by Petersdorf & Beeson
-Fever of >38.3 (101) on several occasions
-Duration of fever >3 weeks
-Uncertain dx after 1 week of study in the hospital

Question 2

Subpopulations with FUO

Answer 2

-Age: children and those with multisystem diseases
-AIDS: depends on CD4 count and viral load

Question 3

Infections causing FUO

Answer 3

-TB»most common
-Abscess
-Osteomyelitis
-Bacterial endocarditis
-Coxiella burnetii (Q fever), T. whipplei, Brucella, Bartonella, Mycoplasma hominis, HACEK group

Question 4

Rheumatologic cause of FUO: Adult Stills Disease

Answer 4

-Sore throat, high fevers, pain in joints and rash
-Daily fevers, arthritis, evanescent rash

Question 5

Rheumatologic cause of FUO: Giant Cell Arteritis

Answer 5

-patients >50 years
-Headache, abrupt loss of vision, fever, anemia, ESR >100, Jaw claudication

Question 6

Malignancies causing FUO

Answer 6

-Lymphoma, esp non-Hodgkins
-Leukemia
-Renal cell carcinoma (approximately 20% of cases present w/ high fever)
-Hepatocellular carcinoma metastatic to the liver
-Multiple myeloma
-Atrial myxomas

Question 7

Drugs that can cause FUO

Answer 7

-Antibiotics
-H1 & H2 blockers
-NSAIDS, Hydralazine, Methyldopa, Quinidine, Procainamide
-Anti-thyroid drugs
-Diagnosis made by therapeutic trial of stopping suspected rug with occasional re-challenge.
-Phenytoin, barbiturates

Question 8

Diagnostic Approach for FUO

Answer 8

-Travel, animal exposure, occupation, hobbies
-Immunosuppression
-Drug/toxin hx, abx exposures
-Localizing symptoms

Question 9

Testing

Answer 9

-ESR, CRP, LDH
-TB skin test
-HIV
-Blood cultures
-Rheumatoid factor, ANA, CK, SPEP
-CT Chest/abdomen/pelvis
-Consider nuclear medicine testing
-Biopsy
-Lumber Puncture