L 73 Toxic Syndromes

Question 1

What is staphylococcal scalded skin syndrome?

Answer 1

A syndrome of toxin-mediated dermatitis
Superficial blistering and exfoliation
Follows an erythematous rash
The bacteria is often elsewhere in the body and the toxin is carried through the blood to affect the skin

Question 2

Staph Scalded Skin Syndrome epidemiology

Answer 2

Generally in children

Question 3

Previous name for Staph Scalded Skin Syndrome and the causative agent

Answer 3

Previously known as Ritter’s disease

Caused by S. aureus

Question 4

Exotoxins from S aureus

Answer 4

S aureus produces two toxins that affect the skin, botha re Epidermolytic toxins
ET-A: chromosome
ET-B: plasmid

Question 5

Actions of the epidermolytic toxins from S aureus

Answer 5

Cleaves desmoglein-1 which is a protein of desmosomes that mediates keratinocyte adhesion
Leads to intaepidermal splitting of tissues and necrosis
Forms bullae and can look like a blistering sun burn

Question 6

Difference between Impetigo and SSSS

Answer 6

The bullae from impetigo are infectious and focal whereas the one from SSSS are systemic and not infectious

Question 7

SSSS clinical manifestations

Answer 7

Site of infection: Oral/nasal cavities, throat, umbilicus, conjunctiva

Early Stage: Fever, irritability, pururlent rhinorrhea, diffuse blanching erythema

Acute Stage: Rash progresses (scarlatiniform–blistering eruptions), mucous membranes hyperemic, but otherwise not affected, conjunctivitis
Skin looks like tissue paper wrinkling, large flaccid bullae at flexures of body
Nikolsky’s sign= press on skin and epidermis separates
Sheet-like desquamation, moist erythematous base revealed

Question 8

What frequently follows an SSSS infection for adults?

Answer 8

Bacteremia and pneumonia

Question 9

SSSS diagnosis

Answer 9

Culture and biopsy needed for definitive diagnosis–try conjunctiva, nasopharynx, feces, pyogenic skin, blood neg for kids might be pos for adults

Question 10

What other conditions present like SSSS and must be considered?

Answer 10

Toxic Epidermal Necrolysis
Stephen Johnson Syndrome
Both stem from drugs that cause a similar presentation except that they also involve the mucous membranes

Question 11

SSSS treatment

Answer 11

Find the focus and treat
IV antibiotics initially
Check for MRSA strains–vancomycin
Supportive care with emollients, fluid and electrolyte balance
Isolate patient and find the carriers

Question 12

What is a superantigen?

Answer 12

Instead of activating only the T-cells that are specific to it, the superantigen activates a much larger number of T-cells and causes a cytokine storm for the activated T-cells

Question 13

Staphylococcal Toxic Shock Syndrome STSS epidemiology

Answer 13

S. aureus present in nares, vagina, rectum, and on skin

Became a significant disease when new highly absorbent tampons were marketed that women left in longer and promoted the growth of S aureus that was already present

Also seen in surgical wounds and wounds packed (kind of like a tampon)

Question 14

Specific reasons why some people were more likely to develop STSS and others were not

Answer 14

Lack antibodies to TSST-1 and fail to develop antibodies in part because of cytokine storm that releases IFN-gamma that inhibits production of antibodies

Question 15

Toxins involved in STSS

Answer 15

TSST-1

Staph Enterotoxin B & A (SEB, SEA)

Question 16

Streptococcal Toxic Shock Syndrome (GAS TSS) epidemiology

Answer 16

Often assoc. with a break in the skin, an invasive disease
Many necrotizing fasciitis cases develop STSS
All ages, most are not immunosuppressed
Risk Factors: diabetes, alcoholism, minor trauma, muscle injury=>vimentin production attracting bac, surgery, child delivery, viral infections, varicella, NSAID use (affects renal clearance)

Question 17

GAS TSS causative agents

Answer 17

GAS–Strep pyogenes most frequent
Group B (Strep agalactiae)
Others

Question 18

GAS TSS virulence factors

Answer 18

GAS: Strep Pyrogenic Exotoxins SpeA, SpeB
All cause massive cytokine release
Streptolysin O–synergist with SpeA for TNF & IL-1 production

M type proteins 1,3,12,28: creates more virulent strain of GAS, antiphagocytic

Mucoid colonies

SSA: streptococcal superantigen
MF: mitogenic factor

Question 19

Clinical manifestations of Staph TSS

Answer 19

S aureus:

1) Fever>102
2) Rash, diffuse macular erythroderma
3) Desquamation 1-2 weeks after, particularly palms and soles
4) Hypotension: Systolic bp in adults

Question 20

Staph TSS diagnosis

Answer 20

Labs negative for other pathogens, never actually have to isolate S aureus
5 of 5 clinical manifestations

Question 21

When to consider GAS TSS

Answer 21

Patient presents from the community in shock

No clear etiology

Question 22

Clinical manifestations of GAS TSS

Answer 22

1) Isolation of GAS from normally sterile sites (blood, CSF, pleaural/peritoneal fluid, tissues, surgical wounds)
2) Hypotension
3) Multiorgan involvement (2 or more)
Renal: creatinine high
Coagulopathy: thrombocytopenia, DIC
Hepatic dysfunction:
ARDS
Erythematous macular rash
Soft tissue necrosis (necrotizing fasciitis, myositis, gangrene)

Question 23

Differences between STSS and GAS TSS

Answer 23

STSS has no soft tissue necrosis, no mention of coagulopathy

Question 24

GAS TSS diagnosis

Answer 24

Meets criteria, GAS isolated form sterile site

Question 25

TSS treatment

Answer 25

1) Supportive of hypotension
2) Nidus therapy: remove tampons & anything else from vaginal canal, drain infectious focus
3) IVIG: immunoglobulins, more effective strep vs staph
4) Eradication of carrier state: S aureus, nares and other sites
5) Antibiotic therapy:
Staph: IV clindamycin, vancomycin
MSSA: Clindamycin and Oxacillin or Nafcillin
MRSA: Clindamycin and vancomycin or Linezolid

Strep: Clindamycin and pnicillin