Insights from Pediatric Grand Rounds: Emergence of Invasive Group A Streptococcus (iGAS)

Shifting our focus once more, today’s exploration has shed further light on the topic of iGAS. Over the past two decades, iGAS cases in Canada have exhibited a twofold increase, prompting a deeper examination. Among the pediatric demographic, recent varicella infections and soft tissue trauma stand out as the principal risk factors, although certain studies have indicated potential connections to viruses such as influenza. The classification of these bacteria as “Group A” stems from the Lancefield categorization. GAS (Group A Streptococcus) are also constituents of our microbiome, taking up residence in the throat, particularly within the pharyngeal region. Notebly, pharyngitis is the most commonly associated ailment.

In the context of adults and children aged three and older, prudence dictates the application of the Citerion criteria prior to commencing GAS screening. This approach is judicious, given that a considerable portion of ENT (Ear, Nose, Throat) infections are caused by viral agents, making the judicious utilization of antibiotics a focal point.

The implications of iGAS are indeed significant. Of paramount concern is toxic shock syndrome, a condition capable of precipitating DIC (Disseminated Intravascular Coagulation), necrotizing fasciitis, and various dermatological manifestations. On an inflammation research point of view, GAS possess superantigens capable of stimulating a substantial proportion—ranging from 20% to 30%—of the T-cell population, a stark contrast to the marginal 0.01% to 0.1% activated by typical antigens. This heightened activation gives rise to an excessive cytokine response, prominently involving IL-6 and TNF. Additionally, M-type 1 and 3 surface proteins have been identified as prominent virulence factors.

Despite ongoing research endeavors, the sudden surge in iGAS cases since 2022 remains unknown and probably multifaceted.

To augment rates of survival, a comprehensive approach has been established:

  1. Supportive Measures: Prioritizing supportive care, including fluid management.
  2. GAS-Targeted Antibiotics: Penicillin is the foremost choice in addressing streptococcal infections.
  3. Adjunctive Therapies: Incorporating klindamycin to target GAS endotoxins, in certain cases along with the consideration of Intravenous Immunoglobulins (though this has mixed research data concerning its efficacy).
  4. Swift Surgical Debridement: Urgently instituting surgical debridement in cases of necrotizing fasciitis, emphasizing the importance of early surgical intervention within a hospital setting.

In instances where a definite diagnosis is established, penicillin emerges as the preferred therapeutic agent. However, in scenarios marked by diagnostic uncertainty, empirical antibiotic treatments are employed. Notably, in Norway, national guidelines thoughtfully integrate the antimicrobial resistance landscape specific to the region, while on a broader international scale, resources like the “Firstline” app offer invaluable assistance.

Regrettably, even with comprehensive care in place, some children inevitably face lingering complications—such as the need for amputation—or even death.

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