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Streptococcal Disease, Emergency Medicine

Basics

Description

- Isolation of GAS from sterile or nonsterile body site - Hypotension - 2 or more of the following: - Renal impairment - Coagulopathy - Liver abnormalities - Acute respiratory distress - Extensive tissue necrosis (NF) - Erythematous rash

- Streptococcal toxic shock syndrome: - Occurs when susceptible host is infected with virulent strain - M protein types 1, 3, and 28 are most common. - Pyrogenic exotoxins (e.g., A, B, and C) produce fever and shock via activation of tumor necrosis factor and interleukins. - Nonsteroidal anti-inflammatory drugs appear to mask or predispose patients. - Risk factors: - Age <10 or >60 yr - Cancer - Renal failure - Leukemia - Severe burns - Corticosteroids

- Pain: - Most common initial symptom of NF: - Out of proportion to physical findings - Often abrupt in onset and severe - Often requires palliative IV narcotics - Usually involves an extremity - May mimic peritonitis, pelvic inflammatory disease, pneumonia, acute MI, or pericarditis

- Renal failure: - Precedes onset of shock in many cases - Dialysis often necessary - Kidney function returns to normal within 4 " 6 wk in survivors.

- Early surgical consultation. Most patients will require an operative procedure (e.g., fasciotomy, surgical debridement, exploratory laparotomy, intraocular aspiration, amputation, or hysterectomy): - Immediate surgery is indicated if there is: - Extensive necrosis or gas - Compartment syndrome - Profound systemic toxicity

  • Increase in frequency of aggressive streptococcal necrotizing skin infection noted in 1980s and dubbed "flesh-eating bacteria. "
  • Affects otherwise healthy patients aged 20 " 50 yr who did not have underlying predisposing diseases.
  • Rapid progression of shock and multiorgan dysfunction, with death occurring within 1 " 2 days.
  • Incidence is 3 " 4 per 100,000 in industrialized countries
  • Invasive infections caused by group A Streptococcus (GAS) include:Necrotizing fasciitis (NF):Progressive, rapidly spreading soft tissue infection located within the deep fascia and subcutaneous fatStreptococcal toxic shock syndrome (STSS):May occur in patients with GAS associated NF.Portals of entry for streptococci include vagina, pharynx, mucosa, and skin.Unknown cause in 50% of cases. "Other " invasive disease defined as isolation of GAS from a normally sterile body site (i.e., sepsis, bacteremic pneumonia, septic arthritis, etc.)
  • Occurs sporadically, with occasional outbreaks in long-term care facilities and hospitals.
  • Rate of invasive GAS disease 6 times the annual incidence of meningococcal disease.

STSS Case Definition

  • Isolation of GAS from sterile or nonsterile body site
  • Hypotension
  • 2 or more of the following:Renal impairmentCoagulopathyLiver abnormalitiesAcute respiratory distressExtensive tissue necrosis (NF)Erythematous rash

Etiology

  • NF:GAS is causative in 10% of cases. Blunt trauma is risk factor.Mixed anaerobic and aerobic organisms are found in 70% of cases.Staphylococcus aureus, Clostridium species, and other enteric organisms
  • Streptococcal toxic shock syndrome:Occurs when susceptible host is infected with virulent strainM protein types 1, 3, and 28 are most common.Pyrogenic exotoxins (e.g., A, B, and C) produce fever and shock via activation of tumor necrosis factor and interleukins.Nonsteroidal anti-inflammatory drugs appear to mask or predispose patients.Risk factors:Age <10 or >60 yrCancerRenal failureLeukemiaSevere burnsCorticosteroids

Diagnosis

Signs and Symptoms

History

  • Pain:Most common initial symptom of NF:Out of proportion to physical findingsOften abrupt in onset and severeOften requires palliative IV narcoticsUsually involves an extremityMay mimic peritonitis, pelvic inflammatory disease, pneumonia, acute MI, or pericarditis

Physical Exam

  • Fever most common sign:Can present with hypothermia, especially if patient is in shock
  • Altered mental status present in 55% of cases
  • Soft tissue infection (erythema and swelling) present in 80%:Indistinct borders, blisters, bullaeNo lymphangitis or lymphadenopathy
  • Influenza-like syndrome in 20%:FeverChillsMyalgiasNausea, vomitingDiarrhea
  • Shock:Present at admission or within 4 " 8 hr in all patientsFrequently persists despite fluids, antibiotics, and vasopressors
  • Renal failure:Precedes onset of shock in many casesDialysis often necessaryKidney function returns to normal within 4 " 6 wk in survivors.
  • ARDS:Occurs in 55% of patients

Essential Workup

  • Suspect NF when pain is out of proportion to exam.
  • Obtain plain films to search for presence of air in soft tissues.
  • Blood cultures should be obtained.

Diagnosis Tests & Interpretation

Lab

  • CBC with differential:Mild leukocytosis with left shift initially
  • Electrolytes, BUN, and creatinine
  • Calcium level:Hypocalcemia in association with fat necrosis from NF
  • Urinalysis:Hemoglobinuria if renal involvement
  • Serum creatine phosphokinase:An elevated or rising level correlates with NF or myositis.
  • Aerobic and anaerobic blood cultures
  • Wound cultures
  • PT/PTT/INR/DIC panel

Imaging

  • Plain films:Gas in soft tissues in 25 " 75% of cases of NF, but not as frequently associated with group A ²-hemolytic streptococcal infectionMore common in mixed anaerobic infections
  • CT scan:Asymmetric thickening of deep fasciaGas
  • MRI:High signal intensity of the fascia in T2-weighted images associated with NF

Diagnostic Procedures/Surgery

Aspiration of involved areas with Gram stain and culture may be useful

Differential Diagnosis

  • Sepsis
  • Cellulitis
  • Erysipelas
  • NF/myositis secondary to infection by another pathogen

Treatment

Pre-Hospital

Stabilize as appropriate

Initial Stabilization/Therapy

  • Maintain ABCs.
  • Treat shock with fluids and vasopressors as needed:Hypotension is often intractable, and up to 10 " 20 L/day may be required.
  • Intubation and mechanical ventilation for:ARDSSevere shockVentilatory failure

Ed Treatment/Procedures

  • Broad-spectrum antibiotics immediately after cultures until the presence of GAS has been confirmed:Clindamycin is a potent suppressor of GAS bacterial toxin synthesis and inhibits M protein synthesis
  • Early surgical consultation. Most patients will require an operative procedure (e.g., fasciotomy, surgical debridement, exploratory laparotomy, intraocular aspiration, amputation, or hysterectomy):Immediate surgery is indicated if there is:Extensive necrosis or gasCompartment syndromeProfound systemic toxicity
  • Droplet precautions for the 1st 24 hr of antibiotic therapy
  • Reports of successful use of IV immunoglobulin
  • Hyperbaric oxygen therapy still controversial

Medication

  • NF due to invasive streptococcal disease (NOTE: In the ED, empiric treatment should be initiated until monomicrobial NF caused by GAS has been confirmed):Clindamycin: 900 mg IV (peds: 40 mg/kg/d), andPenicillin G: 4 million U IV (peds: 250,000 U/d), orVancomycin: 15 mg/kg IV (peds: 10 mg/kg q6h) if patient has penicillin allergy
  • Empiric treatment of NF from all causes (Clostridium perfringens, GAS, methicillin-resistant S. aureus [MRSA], mixed anaerobes/aerobes):Piperacillin/tazobactam 3.5 g IV andClindamycin 900 mg IV andVancomycin 1 g IVFor patients with a penicillin allergy treat with aztreonam 2 g IV, clindamycin 900 mg IV, vancomycin 1 g IV, and metronidazole 500 mg IV

Follow-Up

Disposition

Admission Criteria

ICU admission required for all patients with suspected invasive streptococcal infection. Mortality from GAS NF ¢ ¼20%, but with both NF and STSS, mortality rate increases to 70%.

Discharge Criteria

None

Pearls and Pitfalls

  • Hypotension and shock may require large volumes of IV fluids and vasopressors.
  • Broad-spectrum antibiotics should be administered until the presence of GAS can be confirmed.
  • Surgical consultation should be obtained for debridement.

Additional Reading

  • Martin JM, Green M. Group A streptococcus. Semin Pediatr Infect Dis. 2006;17:140 " 148.
  • Nuwayhid ZB, Aronoff DM, Mulla ZD. Blunt trauma as a risk factor for group A streptococcal necrotizing fasciitis. Ann Epidemiol. 2007;17:878 " 881.
  • Steer AC, Lamagni T, Curtis N, et al. Invasive group A streptococcal disease: Epidemiology, pathogenesis, and management. Drugs. 2012;72(9):1213 " 1227.

See Also (Topic, Algorithm, Electronic Media Element)

  • Pharyngitis
  • Toxic Shock Syndrome

Codes

ICD9

  • 040.82 Toxic shock syndrome
  • 041.01 Streptococcus infection in conditions classified elsewhere and of unspecified site, streptococcus, group A
  • 728.86 Necrotizing fasciitis

ICD10

  • A48.3 Toxic shock syndrome
  • B95.0 Streptococcus, group A, causing diseases classd elswhr
  • M72.6 Necrotizing fasciitis

SNOMED

  • 302809008 Streptococcus pyogenes infection (disorder)
  • 449900006 necrotizing fasciitis due to Streptococcus pyogenes (disorder)
  • 240451000 Streptococcal toxic shock syndrome (disorder)