Module 9a

Question 1

Fever of unknown origin

Answer 1

Fever > 38.8 degrees
Undiagnosed after 2 clinic visits or 3 days in hospital

Question 2

Causes of fever of unknown origin

Answer 2

malignancy

infection

autoimmune disorder

drug reaction

hepatitis

PE/Stroke/MI/CVA

Question 3

Diagnostic workup of FUO

Answer 3

CBC

WBC

Creatinine

LFTs

Urinalysis and culture

2 blood cultures (peripheral, central)

2 view X ray (posterior/anterior, lateral)

lumbar puncture

Other - stool cultures? NP swabs? (depending on symptoms)

Question 4

Treatment of FUO

Answer 4

IV fluids (rehydration)

antipyretics
analgesia
antiemetics

Question 5

Endogenous Pyrogens

Answer 5

IL1
IL6
TNF alpha
IFN

*released by granulocytes, liver, mast cells, macrophages during inflammatory response

Question 6

Signs and symptoms of fever

Answer 6

1. Autonomic Nervous System
   - Release of epinephrine
   - release of norepinephrine
2. Endocrine System
   - Release of ADH
   - Release of epinephrine
3. Behavioural

Diaphoresis
vasoconstriction
shivering
getting blankets
anorexia
HA, loss of concentration

Question 7

SIRS
Systemic inflammatory response syndrome

Answer 7

2 of the following:

Hyper or hypothermia
>38.3 or < 36.0

Tachycardia > 90

Tachypnea

WBC > 12,000 (leukocytosis) or WBC < 400 (leukopenia) or Normal WBC with > 10% blasts (immature forms)

PCO2 < 32mmHg (acidosis)

Question 8

Sepsis

Answer 8

SIRS + Confirmed infection

Infection can be
viral, bacterial, fungal

Question 9

Severe Sepsis

Answer 9

Sepsis +
Signs of end organ damage + BP < 90mmHg
+ Lactate >4mmol/L

Question 10

Septic Shock

Answer 10

Sepsis +
Persistent signs of:
end organ damage (refractory)
BP < 90mmHg
Lactate > 4

Question 11

True / False
We do not treat fever because it is adaptive

Answer 11

False

Fever is adaptive however we treat

Prolonged fever causes damage

Treatment does not decrease the ability of the immune response to fight infection

Question 12

Causes of sepsis

Answer 12

1. Infectious (bacteria, virus, fungi)
2. Noninfectious (trauma, burn)
3. Pro-inflammatory cytokines (TNF alpha, IL1, IL6, IFN)
   - activation coagulation cascade and clotting (DIC)

Question 13

Exotoxins

Answer 13

Released by gram positive bacteria, stimulate the immune response

Question 14

Endotoxins

Answer 14

Released by gram negative bacteria, through lysis of the lipid envelope

Lipopolysaccharide (LPS) lipid A stimulates the release of pro-inflammatory cytokines (TNF alpha, IL1, IL6, IFN) which results in widespread inflammation, vasodilation, coagulation, hypotension

Can results in death 50%

Question 15

3 mechanisms pathogens use to block the immune system

Answer 15

1. Destroy / block components of the immune system

Ex. Staphylococcus secretes toxins to kill phagocytes
Ex. TB secretes anti-oxidants to neutralize phagolysosome
Ex. Biofilm binds Fc region to neutralize antibody activation of complement

2. Mimic Self-Antigen
   Ex. GAS mimic’s cardiac M protein
   Ex. mycoplasma mimics RBC antigen
   Can lead to type II hypersensitivity reactions
3. Change antigenic profile through mutation
   Ex. influenza mutation of H and N antigens