FUO

Question 1

INTRODUCTION

_____________________)refers to a condition in which the patient has an elevated temperature but despite investigations by a physician no explanation has been found..

If the cause is found it is usually a diagnosis of exclusion, that is, by eliminating all possibilities until only one explanation remains, and taking this as the correct one.

Answer 1

Fever of unknown origin (FUO), pyrexia of unknown origin (PUO)or febris e causa ignota (febris E.C.I.

Question 2

MECHANISMS OF HYPERTHERMIA AND ASSOCIATED CONDITIONS

Answer 2

1.Excessive heat production

2.Disorders of heat dissipation

3.Disorders of hypothalamic function

Question 3

Excessive heat production:

Answer 3

exertional hyperthermia,

thyrotoxicosis,

pheochromocytoma,

cocaine,

delerium tremens,

malignant hyperthermia

Question 4

Disorders of heat dissipation:

Answer 4

heat stroke,

autonomic dysfunction

Question 5

Disorders of hypothalamic function:

Answer 5

neuroleptic malignant syndrome,

CVA,

trauma

Question 6

NORMAL BODY TEMPERATURE

For healthy individuals 18 to 40 years of age, the mean oral temperature is

Answer 6

36.8°±0.4°C (98.2°±0.7°F)

Question 7

NORMALBODYTEMPERATURE

Low levels occur at________ and higher levels at _________

Answer 7

6 A.M.

4 to 6 P.M.

Question 8

The maximum normal oral temperature is_________ at 6 A.M. and ____________ at 4 P.M.

Answer 8

37. 2°C (98.9°F)
38. 7°C (99.9°F)

Question 9

____________-: resetting of the thermostatic set-point in the anterior hypothalamus and the resultant initiation of heat-conserving mechanisms until the internal temperature reaches the new level.

Answer 9

Fever

Question 10

________: an elevation in body temperature that occurs in the absence of resetting of the hypothalamic thermoregulatory center

Answer 10

Hyperthermia

Question 11

In 1961 Petersdorf and Beeson suggested the following criteria:

Answer 11

Fever higher than 38.3°C (101°F) on several occasions
Persisting without diagnosis for at least 3 weeks
At least 1 week’s investigation in hospital

Question 12

What is the new definition for FUO?

Answer 12

A new definition which includes the outpatient setting (which reflects current medical practice) is broader, stipulating:

3 outpatient visits or

3 days in the hospital without elucidation of a cause or

1 week of “intelligent and invasive” ambulatory investigation.

Question 13

CLASSES OF FUO

Answer 13

1. classic
2. Nosocomial
3. Immune-defiicient

4.

Question 14

This refers to the original classification by Petersdorf and Beeson. Studies show there are **five categories of conditions: **

Answer 14

Classic FUO

Question 15

Five categories of classic FUO

Answer 15

This refers to the original classification by Petersdorf and Beeson. Studies show there are five categories of conditions:

1. Infections (e.g. abscesses, endocarditis, tuberculosis, and complicated urinary tract infections,)
2. Neoplasms( e.g. lymphomas leukemia’s),
3. Connective tissue diseases (e.g. temporal arteritis and polymyalgia rheumatica, systemic lupus erythematosus and rheumatoid arthritis),
4. Miscellaneous disorders (e.g. alcoholic hepatitis, granulomatous conditions), and
5. Undiagnosed conditions

Question 16

CLASSES OF FUO

______________ refers to pyrexia in patients that have been admitted to hospital for at least 24 hours.

This is commonly related to hospital associated factors such as, surgery, use of urinary catheter intravascular devices (i.e. “drip”, pulmonary artery catheter), drugs (antibiotics induced Clostridium difficile colitis, and drug fever), immobilization (decubitus ulcers)

Answer 16

Nosocomial FUO

Question 17

CLASSES OF FUO

can be seen in patients receiving chemotherapy or in hematologic malignancies.

Fever is concomitant with neutropenia (neutrophil <500/uL) or impaired cell-mediated immunity.

The lack of immune response masks a potentially dangerous course. Infection is the most common cause.

Answer 17

Immune-deficient

Question 18

CLASSES OF FUO

_______________ are a subgroup of the immunodeficient FUO, and frequently have fever. The primary phase shows fever since it has a mononucleosis like illness. In advanced stages of infection fever mostly is the result of a superimposed infections.

Answer 18

HIV-infected patients

Question 19

SOME IMPORTANT CAUSES

______________ is the most frequent cause of FUO.

Answer 19

Extrapulmonary tuberculosis

Question 20

_____________, as sole symptom of an adverse reaction to medication, should always be considered.

Answer 20

Drug-induced hyperthermia

Question 21

Disseminated granulomatoses such as Tuberculosis, Histoplasmosis, Coccidioidomycosis, Blastomycosis and Sarcoidosis are associated with FUO.

Question 22

________________ are the most common cause of FUO in adults.

Answer 22

Lymphomas

Question 23

__________ although uncommon, is another important etiology to consider.

Answer 23

Endocarditis,

Question 24

BACTERIALPYROGENS

Answer 24

1. Lipopolysaccharide (LPS) endotoxin
2. Staphylococcus aureusenterotoxins
3. Staphylococcus aureustoxic shock syndrome toxin (TSST)
4. Group A and B streptococcal toxins

Question 25

Endotoxin binds to LPS-binding protein and is transferred to CD14 on macrophages, which stimulates the release of TNFα.

Answer 25

Lipopolysaccharide (LPS) endotoxin

Question 26

Both Staphylococcustoxins are superantigens and activate T cells leading to the release of interleukin (IL)-1, IL-2, TNFαand TNFβ, and interferon (IFN)-gamma in large amounts

Answer 26

Staphylococcus aureusenterotoxins

Staphylococcus aureustoxic shock syndrome toxin (TSST)

Question 27

_______________

Exotoxins induce human mononuclear cells to synthesize not only TNFαbut also IL1 and IL-6

Answer 27

Group A and B streptococcal toxins

Question 28

MINIMALINITIALDIAGNOSTICWORKUPFORFUO

Answer 28

Comprehensive history
Physical examination
CBC + differential
Blood film reviewed by hematopathologist
Routine blood chemistry
UA and microscopy
Blood (x 3) and urine cultures
Mourad,

Question 29

MINIMAL INITIAL DIAGNOSTIC WORK UP FOR FUO

Answer 29

Comprehensive history
Antinuclear antibodies, rheumatoid factor
HIV antibody
CMV IgM antibodies; heterophile antibody test (if c/w mono-like syndrome)
Q-fever serology (if risk factors)
Chest radiography
Hepatitis serology (if abnormal LFTs)
Mourad, et al. Arch Intern

Question 30

Diagnostic yield of liver biopsy has ranged from_______

Note : Physical exam finding of hepatomegaly or abnormal liver profile are not helpful in predicting abnormal biopsy result.

Complication rate is 0.06% to 0.32%

Answer 30

14% to 17%.

Question 31

The diagnostic yield of bone marrow cultures in immunocompetent individuals has been found to be))))))))

Answer 31

0% to 2%