Toxic shock syndrome without rash in a young child: link with syndrome of hemorrhagic shock and encephalopathy?

Rapid and Rigorous IL-17A Production by a Distinct Subpopulation of Effector Memory T Lymphocytes Constitutes a Novel Mechanism of Toxic Shock Syndrome Immunopathology

Toxic shock syndrome (TSS) is caused by staphylococcal and streptococcal superantigens (SAgs) that provoke a swift hyperinflammatory response typified by a cytokine storm. The precipitous decline in the host's clinical status and the lack of targeted therapies for TSS emphasize the need to identify key players of the storm's initial wave. Using a humanized mouse model of TSS and human cells, we herein demonstrate that SAgs elicit in vitro and in vivo IL-17A responses within hours. SAg-triggered human IL-17A production was characterized by remarkably high mRNA stability for this cytokine. A distinct subpopulation of CD4+ effector memory T (TEM) cells that secrete IL-17A, but not IFN-γ, was responsible for early IL-17A production. We found mouse "TEM-17" cells to be enriched within the intestinal epithelium and among lamina propria lymphocytes. Furthermore, interfering with IL-17A receptor signaling in human PBMCs attenuated the expression of numerous inflammatory mediators implicated in the TSS-associated cytokine storm. IL-17A receptor blockade also abrogated the secondary effect of SAg-stimulated PBMCs on human dermal fibroblasts as judged by C/EBP δ expression. Finally, the early IL-17A response to SAgs was pathogenic because in vivo neutralization of IL-17A in humanized mice ameliorated hepatic and intestinal damage and reduced mortality. Together, our findings identify CD4+ TEM cells as a key effector of TSS and reveal a novel role for IL-17A in TSS immunopathogenesis. Our work thus elucidates a pathogenic, as opposed to protective, role for IL-17A during Gram-positive bacterial infections. Accordingly, the IL-17-IL-17R axis may provide an attractive target for the management of SAg-mediated illnesses.

Staphylococcal toxic shock syndrome erythroderma is associated with superantigenicity and hypersensitivity

Staphylococcal toxic shock syndrome (TSS) has rarely been reported without rash and desquamation. This study describes a patient who met all criteria for TSS except erythroderma and desquamation. The associated staphylococcal superantigen was enterotoxin B. We demonstrate that erythroderma depends on preexisting T cell hypersensitivity amplified by superantigenicity.

Transient bacteraemia: A possible cause of sudden life threatening events

The concept proposed is that transient bacteraemia occurring in otherwise healthy individuals can cause acute life threatening events due to bacterial toxaemia even though the bacteraemia is rapidly cleared (<20 min). This is most likely to occur in infancy at around two to three months of age when anti-toxin IgG reaches its nadir. Sudden unexpected death in infancy, acute life threatening events, haemorrhagic shock and encephalopathy, and the triad of retinal haemorrhage, encephalopathy and bilateral thin film subdural haematomata are conditions which could be caused by this mechanism. Investigations need to be directed to measuring bacterial toxins in blood, CSF and urine; anti-toxin IgG in blood; and bacterial specific nucleic acid sequences in blood, CSF and urine using polymerase chain reaction in order to confirm recent bacteraemia. Furthermore the upper respiratory tract bacterial flora should be mapped in cases and appropriately matched live healthy community controls. Sudden onset, profound life threatening physiological dysfunction occurring in later life could also be caused by a similar mechanism and should be investigated in a similar way; candidate conditions include epilepsy, migraine, stroke and cardiac arrhythmias.

Early burn related gram positive systemic infection in children admitted to a pediatric surgical ward

BACKGROUND

Gram positive infections, including toxic shock syndrome (TSS), may be an early complication following burns, especially in children.

OBJECTIVE

To identify risk factors associated with early burn related gram positive systemic infection (EBGI) in children admitted to a Pediatric Surgical Ward.

METHODS

A retrospective analysis of the records of all EBGI patients treated from January 1995 to December 2004. EBGI patients were defined as having systemic signs of infection appearing in the first 48 h following the burn and associated with: (1) clinical signs of toxin mediated illness and/or (2) positive blood culture of either Staphylococcus aureus or group A beta hemolytic Streptococcus. Demographic and clinical data were also collected from the charts of 150 randomly selected burn patients admitted during the study period.

RESULTS

We identified 13 cases of EBGI (2.5%) among 518 children admitted for thermal burns (mean age: 2.4 years). Three had bacteremia without rash. The 10 other patients were diagnosed as having a toxin mediated disease. S. aureus grew from the burn wound in six patients. All EBGI patients recovered following antibiotic therapy. Significant differences between the groups included: percentage of burned body surface area (6.9% versus 3.9%), and head and face localization (64% versus 31%) in the EBGI and control groups, respectively.

CONCLUSIONS

EBGI is not rare even in pediatric patients with minor-moderate burns. Burns localized to the face or the head may be predisposing factor for such an infection.

Toxic shock syndrome in children: epidemiology, pathogenesis, and management

Toxic shock syndrome (TSS) is an acute, toxin-mediated illness, like endotoxic shock, and is characterized by fever, rash, hypotension, multiorgan involvement, and desquamation. TSS reflects the most severe form of the disease caused by Staphylococcus aureus and Streptococcus pyogenes. A case definition for staphylococcal TSS was well established in the early 1980s and helped in defining the epidemiology. Since the late 1980s, a resurgence of highly invasive streptococcal infections, including a toxic shock-like syndrome, was noted worldwide and a consensus case definition for streptococcal TSS was subsequently proposed in 1993. Both TSS and the toxic shock-like syndrome occur at a lower incidence in children than in adults. Changes in the manufacturing and use of tampons led to a decline in staphylococcal TSS over the past decade, while the incidence of nonmenstrual staphylococcal TSS increased. Nonmenstrual TSS and menstrual TSS are now reported with almost equal frequency. The incidence of streptococcal TSS remains constant after its resurgence, but varies with geographic location. Streptococcal TSS occurs most commonly following varicella or during the use of NSAIDs. Sites of infection in streptococcal TSS are much deeper than in staphylococcal TSS, such as infection caused by blunt trauma, and necrotizing fasciitis. Bacteremia is more common in streptococcal TSS than in staphylococcal TSS. Mortality associated with streptococcal TSS is 5-10% in children, much lower than in adults (30-80%), and is 3-5% for staphylococcal TSS in children.TSS is thought to be a superantigen-mediated disease. Toxins produced by staphylococci and streptococci act as superantigens that can activate the immune system by bypassing the usual antigen-mediated immune-response sequence. The host-pathogen interaction, virulence factors, and the absence or presence of host immunity determines the epidemiology, clinical syndrome, and outcome. Early recognition of this disease is important, because the clinical course is fulminant and the outcome depends on the prompt institution of therapy. Management of a child with TSS includes hemodynamic stabilization and appropriate antimicrobial therapy to eradicate the bacteria. Supportive therapy, aggressive fluid resuscitation, and vasopressors remain the main elements. An adjuvant therapeutic strategy may include agents that can block superantigens, such as intravenous immunoglobulin that contains superantigen neutralizing antibodies.

Lack of muco-cutaneous signs of toxic shock syndrome when T cells are absent: S. aureus shock in immunodeficient adults with multiple myeloma

Staphylococcal toxic shock syndrome (TSS) is an acute life threatening disease. The diagnosis can be made clinically based on diagnostic criteria. The clinical manifestations are caused in large part by there lease of high levels of T-cell-derived cytokines as a result of potent toxins, also called superantigens (SAg), produced by Staphylococcus aureus, but it is not clear which clinical symptoms/signs are strictly T-cell dependent. Here, we report on three adults with multiple myeloma (MM) presenting with S.aureus sepsis/shock, and two patients with typical TSS. The MM patients had compromised humoral immunity because of depression of normal immunoglobulin (Ig) levels at the expense of the M protein. In addition, their T cells were absent due to high dose chemotherapy initiated for bone marrow trans-plantation. The MM cases lacked mucosal hyperemia, erythroderma and desquamation, but were otherwise indistinguishable from the TSS cases. All patients grew S. aureus and in each case, SAg genes were detected by PCR. In several cases, the plasma contained biological SAg activity resulting in VP specific proliferation of indicator T cells in vitro. The same specific activity was observed with the supernatant fluids of S. aureus broth cultures from the respective bacterial isolates. This confirms the presence of bio-active toxins in the plasma but did not lead to full blown TSS when T cells were lacking.Thus, S. aureus sepsis/shock can be clinically distinguished from typical TSS, and we suggest that mucocutaneous manifestations of TSS are the most telling signs of massive T-cell-dependent cytokine release.

Hemorrhagic shock and encephalopathy syndrome: neurologic features

Hemorrhagic shock and encephalopathy syndrome (HSES) is a severe disease that affects previously healthy infants of less than 1 year of age and is associated with significant mortality and neurologic morbidity. It is characterized by sudden onset of shock, convulsions and coma, bleeding due to severe coagulopathy, fever, diarrhea, metabolic acidosis, and hepatorenal dysfunction. Central nervous system involvement with recurrent seizures and brain edema is the most common cause of high mortality and neurological morbidity. In this report, we describe four patients of HSES and review the initial and follow-up neurological features, electroencephalography findings, and the results of neuroradiological examinations of this catastrophic illness.