Streptococcal Toxic Shock Syndrome Due to Invasive Group A Streptococcal M1UK Strain Infection in a Previously Healthy Child.

Invasive group A streptococcal (iGAS) infections are known to be potentially life-threatening. Few detailed pediatric cases of streptococcal toxic shock syndrome (STSS) caused by iGAS with the M1UK strain have been reported. This report describes the case of a child with STSS due to M1UK strain, with detailed documentation of the treatment progress. A 10-year-old female patient without predisposing factors associated with iGAS, initially presented with pneumonia and developed progressive multi-organ failure. A precise diagnosis by the primary hospital's attending physician and effective critical care in the pediatric intensive care unit (PICU) at a tertiary children's hospital led to lifesaving and favorable functional outcomes. The clinical course highlights the importance of recognizing the common presentation of iGAS and prompt medical coordination between general hospitals and PICU. Furthermore, public health measures against iGAS infection are just as important as early diagnosis and treatment to prevent deaths in the community after rapid deterioration.