6.9. Skin and Soft Tissue Infection - Toxin Mediated Syndromes

Question 1

What causes Toxin Mediated Syndromes?

Answer 1

Superantigens, a group of Pyrogenic Exotoxins

Question 2

How do Superantigens activate the immune system?

Answer 2

Not via the normal contact between Antigen Presenting Cell (APC) and T-Cells:
.1 Superantigens bypass APC, and attach directly onto the T-Cell Receptors, activating up to 20% of the pool, instead of the normal 0.01%
2. This causes a massive burst in Cytokine release

Question 3

What does the massive burst in Cytokine release cause?

Answer 3

1. Endothelial Leakage
2. Haemodynamic Shock
3. Multi-organ failure
4. Death

Question 4

What is the most common causative infectious agent of Toxin Mediated Syndromes?

Answer 4

1. Strains of Staphylococcus Aureus:
2. a) Toxic Shock Syndrome Toxin-1 (TSST-1)
3. b) Endothelial A Receptor (ETA) and Endothelial B Receptor (ETB)
4. Strains of Streptococcal Pyogenes:
5. a) Toxic Shock Syndrome Toxin-1 (TSST-1)

Question 5

What are the most common Toxin Mediated Syndromes?

Answer 5

1. Staphylococcal Toxic Shock Syndrome
2. Streptococcal Toxic Shock Syndrome
3. Staphylococcal Scalded Skin Syndrome
4. Panton-Valentine Leucocidin Toxin Syndrome

Question 6

What is Toxic Shock Syndrome associated with?

Answer 6

1. 1980’s - high absorbency tampons during menses
2. Small skin infections due to Staphylococcus Aureus secreting Toxin Shock Syndrome Toxin -
   1 (TSST-1)

Question 7

What is the Diagnostic Criteria for Staphylococcal Toxic Shock Syndrome?

Answer 7

1. Fever
2. Hypotension
3. Diffuse Macular Rash
4. Three of the following organs involved: Liver, Blood, Renal, GI, CNS, Muscular
5. Isolation of Staphylococcus Aureus from Mucosal / Normally Sterile Sites
6. Production of TSST1 by isolate
7. Development of antibody toxin during convalescence

Question 8

What is Streptococcal Toxic Shock Syndrome associated with?

Answer 8

The presence of Streptococci in deep seating infections, such as:

1. Erysipelas
2. Necrotising Fasciitis

Question 9

Is the Streptococcal Toxic Shock Syndrome mortality rate higher or lower than the Staphylococcal Toxic Shock Syndrome?

Answer 9

Streptococcal Toxic Shock Syndrome has a much higher mortality rate:

1. Streptococcal Toxic Shock Syndrome - 50%
2. Staphylococcal Toxic Shock Syndrome - 5%

Question 10

What is the treatment of Toxic Shock Syndrome?

Answer 10

1. Removal of offending agent (e.g. Tampon)
2. I.V. Fluids
3. Ionotropes
4. Antibiotics
5. I.V. Immunoglobulins
6. Urgens Surgical Debridement of the infected Tissue (Strep. TSS)

Question 11

What is Staphylococcal Scalded Skin Syndrome infection due to?

Answer 11

A particular strain of Staphylococcus Aureus which produces:

1. Exfoliative Toxin A
2. Exfoliative Toxin B

Question 12

How is Staphylococcal Scalded Skin Syndrome characterised?

Answer 12

1. Widespread Bullae

2. Skin Exfoliation

Question 13

Which group of people is Staphylococcal Scalded Skin Syndrome most commonly found?

Answer 13

Children

Note - it can occur in adults as well

Question 14

What is the treatment of Staphylococcal Scalded Skin Syndrome?

Answer 14

1. I.V. Fluids

2. I.V. Antimicrobials

Question 15

What is the mortality rate of Staphylococcal Scalded Skin Syndrome?

Answer 15

3% in children

Higher in adults who are often immunocompromised

Question 16

What is the Panton-Valentine Leucocidin Toxin?

Answer 16

A Gamma Haemolysin

Question 17

How is the Panton-Valentine Leucocidin Toxin transferred?

Answer 17

It can be transferred from one strain so Staphylococcus Aureus to another (including MRSA)

Question 18

What can the Panton-Valentine Leucocidin Toxin cause?

Answer 18

1. Skin and Soft Tissue Infection

2. Haemorrhagic Pneumonia

Question 19

Who does the Panton-Valentine Leucocidin Toxin tend to affect?

Answer 19

1. Children

2. Young Adults

Question 20

How do patients with Panton-Valentine Leucocidin Toxin Syndromes present?

Answer 20

Recurrent Boils (Furunculosis) which are difficult to treat

Question 21

How are Panton-Valentine Leucocidin Toxin Syndromes treated?

Answer 21

Antibiotics which reduce the Toxin Production