Toxic shock syndromes

Introduction

• Classical: Staph aureus or Group A strep
• Difficult to differentiate from sepsis

Differences

Pathophysiology – Staph

• Superantigen-mediated
• Bind to histocompatibility complex class II and T-cell receptors on APC’s with massive T cell and cytokine release leading to SIRS response
• 9% of women are vaginally colonised with Staph, only 1% of whom are toxigenic
• Almost all menstrual TSS is due to TSST-1 toxin vs. only half of non-menstrual cases
• Wounds harbouring toxigenic S. aureus may not even appear infected
• Wound swabs often positive for S. aureus (despite BC + in only 5%)

Case definition (Staph)

• Probable case = 4 or more clinical criteria + lab criteria met
• Confirmed = 5 clinical criteria + lab criteria met including desquamation (unless dies before this)
• Clinical criteria
  • Fever >38.9
  • Diffuse macular erythroderma (like sunburn)
  • Desquamation 1-2 weeks after rash
  • Hypotension
  • Multiorgan failure (3 or more organ systems): GI, CK, mucous membrane hyperaemia, renal, hepatic, Plt <100, CNS
• Lab criteria
  • Negative BC or CSF culture (BC can be positive for Staph. Aureus)
  • Negative serology for lepto, measles and rocky mountain spotted fever

Differential diagnosis

• Streptococcal toxic shock syndrome
• Myonecrosis due to Clostridium perfringens
• Toxic shock syndrome due to Clostridium sordellii associated with gynaecological surgery, childbirth, miscarriage and abortions (often without fever)
• Staphylococcal scalded skin syndrome (lacks hypotension or organ dysfunction)
• Sepsis or septic shock of any cause (erythroderma is distinguishing factor)
• Rocky mountain spotted fever
• Leptospirosis
• Meningococcaemia
• SJS
• TEN
• Kawasaki’s disease

Treatment

• Treat as for sepsis
• Remove any nidus of infection (including tampon/nasal packing)
• Consider coverage of MRSA
  • Options:
    • Vancomycin 25-30mg/kg load then 15mg/kg BD
    • Linezolid 600mg IV BD
      • May directly suppress TSST-1 production
• If low risk of MRSA
  • Flucloxacillin 2g q4h +- Clindamycin 900mg IV q8h
    • Clindamycin can be added to inhibit protein synthesis and TSST-1 production but should not be used as monotherapy
• IVIG
  • Reserved for failure to improve over 6 hours despite above
  • 1-2g/kg
  • Contraindicated in IgA deficiency
• High-dose corticosteroids not recommended

Streptococcal TSS

• Mostly in older patients and those under 1 year old with necrotising fasciitis
• Around 3.4% of invasive Group A strep infections (S. pyogenes) suffer this
• Pathophysiology
  • Streptococcal pyrogenic exotoxins A and B
  • Act in same way as staph toxins
  • BC positive in 60% and wound swabs almost always positive

Streptococcal TSS

• Probable case: All clinical criteria met + absence of other cause + isolation of GAS from non-sterile site
• Confirmed case: All clinical criteria met + Isolation of GAS from sterile site
• Clinical criteria
  • Hypotension
  • Multiorgan dysfunction (2 or more): Renal, Plt <100 or DIC, hepatic, ARDS, generalised erythematous macular rash, soft tissue necrosis

Treatment

• PipTaz 4.5 q8h or meropenem 1g IV q8h + clindamycin 900mg IV q8h
• If MRSA prevalent – add vancomycin
• Once GAS confirmed, narrow spectrum to Pen G 4 million units IV q4h + clindamycin
• IVIG may play a role

Last Updated on October 2, 2020 by Andrew Crofton