FEVER OF UNKNOWN ORIGIN

Question 1

FUO is now defined as

Answer 1

1. Fever ≥38.3C (≥101 F) on at least two occasions
   
   2. Illness duration of ≥3 weeks
   3. No known immunocompromised state
   4. Diagnosis that remains uncertain after a thorough history-taking, physical examination, and the obligatory investigations
      • ESR and CRP
      • CBC
      • electrolytes, creatinine
      • total protein
      • AST, ALT, Alk phos
      • lactate dehydrogenase
      • creatine kinase
      • ferritin
      • ANA and RF
      • protein electrophoresis
      • urinalysis
      • blood cultures (n = 3)
      • urine culture
      • chest x-ray
      • abdominal ultrasonography
      • TST or IGRA

Question 2

Up to half of all infections in patients with FUO outside Western nations are caused by ____________

Answer 2

M. tuberculosis

Question 3

The most common diagnosis of FUO among the neoplasms

Answer 3

Malignant lymphoma

Question 4

Fever artificially induced by the patient—for example, by IV injection of contaminated water

Answer 4

Factitious fever

Question 5

Is the term when the patient is normothermic but manipulates the thermometer

Answer 5

Fraudulent fever

Question 6

TRUE OR FALSE: FUO in the elderly results from an atypical manifestation of a common disease

Answer 6

TRUE

• FUO in the elderly results from an atypical manifestation of a common disease, among which giant cell arteritis and polymyalgia rheumatica are most frequently involved

Question 7

The most common infectious disease associated with FUO in elderly patients

Answer 7

Tuberculosis

Question 8

TRUE OR FALSE: Performing more than three blood cultures or more than one urine culture is useless in patients with FUO in the absence of PDCs

Answer 8

TRUE

• Repeating blood or urine cultures is useful only when previously cultured samples were collected during antibiotic treatment or within 1 week after its discontinuation

Question 9

TRUE OR FALSE: Patients should be asked to return during a febrile episode so that the history, physical examination, and laboratory tests can be repeated during a symptomatic phase

Answer 9

TRUE

• In patients with recurrent fever lasting >2 years, it is very unlikely that the fever is caused by infection or malignancy.

Question 10

TRUE OR FALSE: Empirical therapeutic trials with antibiotics, glucocorticoids, or antituberculous agents should be avoided in FUO except when a patient’s condition is rapidly deteriorating

Answer 10

TRUE

• Antibiotic or antituberculous therapy may irrevocably diminish the ability to culture fastidious bacteria or mycobacteria

Question 11

When to initiate empiric antibiotic treatment in patients with FUO?

Answer 11

Hemodynamic instability or neutropenia is a good indication for empirical antibiotic therapy

Question 12

When to start a trial of therapy for tuberculosis?

Answer 12

If TST or IGRA is positive or if granulomatous disease is present with anergy and sarcoidosis seems unlikely

• If the fever does not respond after 6 weeks of empirical antituberculous treatment, another diagnosis should be considered.

Question 13

TRUE OR FALSE: In patients in whom FUO remains unexplained, prognosis is favorable

Answer 13

TRUE

• FUO-related mortality rates have continuously declined over recent decades
• the risk of death related to FUO is dependent on the underlying disease

Question 14

A trial of what drug can be considered in patients whose FUO has not been diagnosed after later-stage diagnostic tests

Answer 14

Therapeutic trials with ANAKINRA can be considered in patients whose FUO has not been diagnosed after later-stage diagnostic tests

• Anakinra, a recombinant form of the naturally occurring IL-1 receptor antagonist (IL-1Ra), blocks the activity of both IL-1α and IL-1β.

Question 15

Characterized by urticaria, bone pain, and monoclonal gammopathy

Answer 15

Schnitzler syndrome

Question 16

The most important step in the diagnostic workup in patients with FUO?

Answer 16

The search for potentially diagnostic clues (PDCs) through complete and repeated history-taking and physical examination and the obligatory investigations