1: Fever of Unknown Origin

Question 1

Define fever of unknown origin (FUO).

Answer 1

• Prolonged fever (rectal temp > 101°F or 38.3°C) or oral temp > 100.0°F (37.8°C) for 2 - 3 weeks or more without an etiology.

OR

• No specific diagnosis after 3-7 days or 3 days of outpatient visits, extensive studies, and continued fever.

Question 2

What is the cause of many FUO?

Answer 2

Atypical presentations of common disorders.

Question 3

What are some DDx for FUO in those <6 yo?

Answer 3

1. UTI / Pyelonephritis
2. Respiratory infx
3. Localized infx (abscess, osteomyelitis)
4. Juvenile arthritis
5. Leukemia

Question 4

What are some DDx for FUO in adolescents?

Answer 4

1. TB
2. Inflammatory bowel dz
3. Autoimmune dz
4. Lymphoma
5. UTI / Pyelonephririts
6. Respiratory infx
7. Localized infx (abscess, osteomyelitis)
8. Juvenile arthritis
9. Leukemia

Question 5

When do you admit to the hospital with FUO?

Answer 5

1. Very ill
2. Concern for Munchausen’s by proxy
3. FTT
4. Very young
5. Follow up unreliable

Question 6

T/F Empiric ABX are used for FUO.

Answer 6

False. No ABX unless cause is known or likely known.