Overview
Definition:
Kawasaki Shock Syndrome (KSS) is a rare but severe manifestation of Kawasaki disease (KD), characterized by the presence of KD criteria along with hypotension and evidence of myocardial dysfunction
Toxic Shock Syndrome (TSS) is a serious, life-threatening illness caused by the release of toxins from certain bacterial infections, primarily Staphylococcus aureus or Streptococcus pyogenes, leading to fever, rash, hypotension, and multi-organ involvement.
Epidemiology:
Kawasaki disease is the leading cause of acquired heart disease in children in developed countries, with KSS occurring in approximately 1-3% of KD patients, predominantly in infants and young children
TSS is less common in children than adults, with incidence varying by geographic location and Staphylococcus aureus toxin production strains
pediatric cases are reported but are significantly outnumbered by typical KD.
Clinical Significance:
Differentiating KSS from TSS is critical due to distinct etiologies, diagnostic pathways, and management strategies
Misdiagnosis can lead to delayed or inappropriate treatment, significantly increasing morbidity and mortality, particularly cardiac complications in KSS and multi-organ failure in TSS.
Clinical Presentation
Kawasaki Shock Syndrome:
High fever lasting >5 days
Conjunctivitis (bilateral, non-exudative)
Oral mucosal changes (erythema, cracked lips, strawberry tongue)
Extremity changes (edema/erythema of hands/feet, desquamation)
Polymorphous rash
Cervical lymphadenopathy (>1.5 cm)
NEW: Hypotension
Signs of myocardial dysfunction (e.g., tachycardia disproportionate to fever, poor peripheral perfusion, gallop rhythm, decreased cardiac output).
Toxic Shock Syndrome:
Sudden onset of high fever (>38.9°C)
Diffuse erythematous rash (macular, blanching), which may desquamate 1-2 weeks later
Hypotension (systolic BP <90 mmHg in adults, <70 mmHg in children <16 yrs, or <5th percentile for age)
Involvement of three or more organ systems: gastrointestinal (vomiting, diarrhea), musculoskeletal (myalgia, elevated CK), renal (elevated BUN/Cr), hepatic (elevated LFTs), hematologic (thrombocytopenia), central nervous system (confusion, disorientation).
Diagnostic Criteria:
Kawasaki Disease: Clinical criteria for KD with fever for >=5 days plus at least 4 of 5 principal clinical features
KSS: KD criteria PLUS hypotension
Toxic Shock Syndrome: Clinical criteria as described above, supported by laboratory evidence of staphylococcal or streptococcal infection (e.g., positive blood, throat, or wound cultures, or elevated anti-TSST-1 antibody titers if available).
Diagnostic Approach
History Taking:
Detailed history of fever duration and characteristics
Exposure to sick contacts
Recent antibiotic use
Any history of skin trauma or surgical procedures
Presence of associated symptoms like vomiting, diarrhea, myalgia, or confusion
In KSS, focus on KD criteria and signs of shock
In TSS, emphasize symptom onset, progression, and extent of organ involvement.
Physical Examination:
Thorough assessment of vital signs, including BP, HR, RR, and O2 saturation
Meticulous examination for all KD criteria: conjunctiva, oral mucosa, extremities, and rash
Assess for signs of shock: cool extremities, delayed capillary refill, diminished pulses, altered mental status
Systemic review for TSS organ involvement: GI, MSK, renal, hepatic, CNS findings.
Investigations:
For suspected KSS: CBC with differential (leukocytosis, thrombocytosis later), ESR/CRP (markedly elevated), urinalysis (pyuria), liver function tests, albumin
Echocardiography is crucial for assessing cardiac status (coronary artery abnormalities)
For suspected TSS: CBC (leukocytosis, thrombocytopenia), LFTs, renal function tests, CK, blood cultures, wound cultures if applicable, urine culture
Consider inflammatory markers (ESR/CRP) and cardiac biomarkers (troponin, BNP) in severe cases.
Differential Diagnosis:
For KSS: Scarlet fever, measles, adenovirus, enterovirus, Stevens-Johnson syndrome, leptospirosis, atypical presentations of other febrile exanthems
For TSS: Meningococcemia, Rocky Mountain spotted fever, viral exanthems, drug reactions, rickettsial infections, other systemic inflammatory syndromes
In KSS, differentiating from other shock states with fever is paramount
In TSS, distinguishing from other sepsis syndromes is key.
Management
Initial Management:
For both conditions, immediate hemodynamic stabilization is paramount
Intravenous fluids are essential for hypotension
In KSS, early intravenous immunoglobulin (IVIG) and aspirin are the cornerstones of therapy
In TSS, fluid resuscitation, vasopressor support if needed, and prompt source control (e.g., drainage of abscess, removal of foreign body) are crucial
Broad-spectrum antibiotics are indicated for TSS.
Medical Management Kss:
Intravenous immunoglobulin (IVIG) 2 g/kg as a single infusion over 10-12 hours
Aspirin 80-100 mg/kg/day in divided doses during the febrile phase, then 3-5 mg/kg/day as a single daily dose for at least 6-8 weeks, or longer if coronary artery abnormalities persist
Corticosteroids may be considered for refractory cases or those with significant cardiac involvement.
Medical Management Tss:
Antibiotic therapy targeting Staphylococcus aureus and Streptococcus pyogenes: Clindamycin or Vancomycin (if MRSA suspected) plus a beta-lactam antibiotic like Nafcillin or Oxacillin
Supportive care includes fluid resuscitation, vasopressor agents (e.g., norepinephrine, dopamine) for persistent hypotension, mechanical ventilation if respiratory failure occurs, and dialysis for renal failure
IVIG is also recommended for severe TSS to neutralize toxins.
Supportive Care:
Close monitoring of vital signs, fluid balance, and organ function is essential for both
Cardiac monitoring is vital for KSS patients
Nutritional support and pain management are important
Management of fever and inflammatory markers is also key.
Complications
Early Complications Kss:
Myocardial infarction, myocarditis, pericarditis, valvular regurgitation, acute renal failure, hydrops of the gallbladder, aseptic meningitis, arthritis
The most feared early complication is the development of coronary artery aneurysms.
Early Complications Tss:
Cardiogenic shock, acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation (DIC), acute kidney injury (AKI), hepatic dysfunction, neurologic deficits, severe skin peeling leading to secondary infections.
Late Complications:
For KSS: Coronary artery aneurysms leading to thrombosis, stenosis, or rupture, potentially causing myocardial infarction or sudden death in adulthood
For TSS: Residual organ damage, chronic renal insufficiency, or long-term sequelae from severe sepsis.
Prognosis
Factors Affecting Prognosis Kss:
Delayed diagnosis and treatment are associated with a higher risk of coronary artery abnormalities
Age (infants <1 year), male sex, and initial fever duration are also risk factors
Early aggressive treatment with IVIG and aspirin significantly improves outcomes.
Factors Affecting Prognosis Tss:
Prognosis depends on the severity of organ involvement, promptness of treatment, and presence of complications like shock and DIC
Rapid initiation of appropriate antibiotics, fluid resuscitation, and toxin neutralization with IVIG improve survival
Mortality rates, though reduced, remain significant.
Outcomes:
With timely and appropriate management, most children with KSS will recover without significant long-term sequelae
However, coronary artery abnormalities can persist, requiring long-term follow-up
For TSS, survival rates have improved dramatically with modern critical care but can still be high in severe cases.
Key Points
Exam Focus:
Distinguish KSS from TSS based on clinical criteria, etiology (autoimmune/inflammatory vs
bacterial toxin), and typical presentations
Remember the core KD criteria and the addition of shock in KSS
For TSS, recall the organ system involvement and causative bacteria
Recognize the importance of IVIG and Aspirin in KSS, and antibiotics and supportive care (including IVIG) in TSS.
Clinical Pearls:
In a febrile child with rash and hypotension, consider both KSS and TSS
Look for the specific KD features if KSS is suspected
Ask about GI symptoms, myalgias, and neurological changes for TSS
Early echocardiography is crucial in suspected KSS, especially if shock is present
Prompt antibiotic therapy and source control are life-saving in TSS.
Common Mistakes:
Mistaking KSS for a typical viral exanthem with fever
Delaying IVIG and aspirin in KD
Underestimating the severity of hypotension in children
Failing to consider TSS in a child with fever, rash, and shock, especially with GI symptoms
Not initiating broad-spectrum antibiotics promptly for suspected TSS
Inadequate fluid resuscitation and vasopressor support in shock.