-IBIS-1.5.0-
tx
immune system
fever of unknown origin
diagnoses

definition and etiology

definition: Fever is the dominant sign in a patient's illness but the cause is undetectable. The term usually refers to a rectal temperature greater than or equal to 101.3°F (38.3°C) for at least 2-3 weeks and where the cause cannot be identified after considerable testing.

etiology: In children, infection is responsible for 50% of FUO (viruses in those under 2; endocarditis and mononucleosis over 6); collagen inflammatory disease causes 20% (especially rheumatoid arthritis and inflammatory bowel disease); neoplasms cause 10% (esp. leukemia); miscellaneous accounts for 10% (milk allergy, thyroiditis); and the cause is unidentifiable in approximately 12%. In adults with FUO infection, collagen vascular disease, and neoplasms are most often found; 10% of adults also go undiagnosed.

signs and symptoms

• Fever.
• Anorexia, weight loss, chills/sweats, fatigue.
• Signs and symptoms specific to the underlying cause.

lab findings:
• Possibly increased ESR: with collagen diseases or cancer.
• Bone marrow examination for leukemia.
• Tissue biopsy.
• Blood cultures.
• Serologic tests.
• May see increased or decreased WBC, shift to left, or increased lymphs.

course and prognosis

Course and prognosis relate to the underlying pathology. Total recovery by group is as follows: infection 90%; collagen diseases 10%; cancer, depends on the type and stage of tumor; unidentified 33%.

differential diagnosis

• Determine primary cause.


footnotes