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Explore the diagnostic journey of a pediatric patient with Streptococcal Toxic Shock Syndrome, from initial symptoms to treatment plans. Key points include virulence factors, pathogenesis, and clinical presentation.
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Intern seminar 時間:2006-12-22 8:00 am 地點: 4C會議室 Presented by Int郭良維 Supervisor:邱元佑醫師
Basic information • Name: 王O淮 • Ward No.: 4C79 • Age/Sex: 7y/o/male • Admission day: 2006/12/13 • Chart No.: 07516921 Chief complaint • Fever with myalgia noted since 12/03
Brief history Fever up to 38+℃ with sore throat and vomiting, bilateral myalgia of lower legs(+) sent to LMD but no response to treatment Sustained fever 38+ ℃, lethargy(+)sent to SinLau H. where metabolic acidosis, shock and ARF (Cr.:2.6) were impressed susp. Septic shock admitted to PICU and received antibiotics therapy 12/03 12/06 Vancomycin 12/6~12/7 Cefotaxime 12/6~12/9 Clindamycin 12/6~12/11 Aq-penicillin 12/7~12/13
Culture of blood, urine and throat swab from SinLau H. (12/08) Group A Streptococcus
Brief history • Transferred to general ward on 12/11 • Bilateral lower legs discomfort • Soreness of lumbosacral area • Intermittent fever: especially at night • Referred to our hospital for further survey
Birth history • G1P1, C/S, GA: 38 weeks, BBW: 3500g • DOIC(-), PROM(-) • Feeding: on full diet • Vaccination: on schedule • BW: 24.8kg(50-75th%), BL: 119.4cm(25-50th%) • Developmental milestones: WNL Past history • No other major disease • Bilateral AOM history • NKDA
Review of system • Review of Systems: • General: • poor activity (-), Fever (+), Body weight loss(-), Malaise (-) • Cardiovascular • Tachycardia (-), Central cyanosis (-) • Pulmonary • Cough(+) with sputum(-), Wheezing(-), tachypnea(+) with retraction (-) • Alimentary • poor appetite (-), abdominal discomfort (-), nausea (-), vomiting (-) • bowel habit change (-), diarrhea (-) • Genitourinary • dysuria (-), nocturia (-), bilateral flank pain(+) • Skeletal • ROM: no limitation
Physical examination • Appearance: well • Vital sign: • BT: 37.60C, P: 114/min, R: 42/min, BP: 95/65 mmHg • activity: fair • Head: • conj:mild pale; sclera: not icteric • throat:injected; tonsil: not enlarged • Neck: supple, bil. small LAP(+), JVE(-) • Chest: symmetric expansion, subcostal retraction( - ) • B.S.: clear,no crackles • H.S.: tachycardia, no obvious murmur, friction rub (+) at LLSB • Abd: soft, not distended; BS: normo-active • L/S: impalpable / impalpable, • No tenderness, No rebounding pain • Bil. flank knocking pain (+) • Extremities: freely movable, pitting edema (-) • R’t knee & L’t popliteal fossa: tenderness/heat/swelling/erythematous change:all (-) • Lumbosacral area: a tender point, no swelling or erythematous change • Skin: turgor fine, no rash
Lab data (12/13) U/A
Tentative diagnosis • Streptococcal toxic shock syndrome • Susp. APN or renal abscess • Susp. Pericardial effusion • Susp. Osteomyelitis
Plans • Aq-penicillin 2MU iv q6h • Clindamycin 350mg iv q8h • Arrange cardiac echo & renal echo • Arrange three-phase bone scan
CXR 12/11 at SinLau 12/13
Admission course • Persistent fever up to 39+℃ 2-3 times/day • Three-phase bone scan: negative finding; osteomyelitis is not favored. • Follow-up renal echo: a 1*1 cm abscess in left kidney is suspected • Abdominal echo • MSL: 7.4cm • Hepatic veins are mild dilated Hepatomegaly
Admission course 12/16 12/19
Discussion Streptococcal toxic shock syndrome
Group A Streptococcus • Facultative gram-positive, β-hemolytic coccus • Only known reservoir in nature is the skin and mucous membranes of the human host. • The most common portals of entry for streptococcal infections: skin, vagina, or pharynx • 45% of cases cannot be identified
Virulence factors • M protein • An important virulent determinant • A filamentous protein anchored to the cell membrane: antiphagocytic properties • M types 1, 3, 12 and 28 • Lipoteichoic acid • Another cell wall constituent • Promote colonization by binding to fibronectin • Hyaluronic acid capsule • Resist phagocytosis
Virulence factors • Pyrogenic exotoxins • Three antigenically distinct forms: A,B,C • Responsible for Scarlatiniform rash and for shock • Streptolysin • S: damage membranes of neutrophils and platelets • O: lysis RBCs; toxic to neutrophils, platelets, and mammalian heart muscle
Pathogenesis • Anti-phagocytic properties • M-protein • GAS protease • Extracellular digestive enzymes: facilitate the spread of infection • Streptokinase: lysis fibrin • Streptolysins: local thrombosis • Deoxyribonuclease: pus formation • Hyaluronidase, proteinase: connective tissue digestion Suppurative complications
Pathogenesis • Mechanisms of fever induction • Pyrogenic exotoxins induce human mononuclear cells to synthesize TNF-α, IL-1, IL-6 • Cytokine induction • Pyrogenic exotoxins and a number of staphylococcal toxins bind to Class ⅡMHC complex of APCs and V-β region of T cell receptor T cell proliferation with concomitant production of cytokines
Clinical spectrum of GAS infections • Suppurative: • Pharyngitis • Scarlet fever • impetigo • Tonsillopharyngeal cellulitis or abscess, otitis media, sinusitis • Necrotizing fasciitis • Streptococcal bacteremia • Streptococcal toxic shock syndrome • Nonsuppurative: • Rheumatic fever • PSGN
Definition of STSS • Hypotension plus two or more • Renal impairment • Coagulopathy • Hepatic involvement • Adult respiratory distress syndrome • Generalized erythematous macular rash • Soft tissue necrosis • Definite case • Clinical criteria plus group A streptococcus from a normally sterile site • Probable case • Clinical criteria plus group A streptococcus from a nonsterile site
Risk factors • Persons of all ages may be afflicted with GAS TSS and most are immunocompetent. • Associated with the development of severe GAS infections: • Minor trauma • Injuries resulting in hematoma, bruising, muscle strain • Surgical procedure • Viral infections (varicella) • Use of NSAIDs
GAS bacteremia • OBJECTIVE: The aim of this study was to review the clinical features, laboratory findings and the risk factors associated with invasive group A streptococcal infections in children admitted to our institution over a 9-year period(1990-1999) • Included group: 41 children who had a positive blood culture from any other sterile site; mean age: 4.3+/-2.5 years Indian J Pediatr. 2004 Oct;71(10):915-9.
GAS bacteremia • 16: onlybacteremia; 25: bacteremia + the following: • Cellulitis: 13 • Osteomyelitis: 6 • Pneumonia: 3 • Meningitis: 1 • Pharyngitis: 3 • STSS: 2 • Primary varicella infection constituted the most common predisposing factor for invasive GAS infections and occurred in 11 (27%) patients. Indian J Pediatr. 2004 Oct;71(10):915-9.
GAS bacteriuria • 24 cases with bacteriuria seen in a tertiary care hospital in southern India (1988-1993): • 9: asymptomatic bacteriuria • 12: dysuria or frequency • 3: fever without localizing signs • All patients have systemic or local conditions predisposing to UTI. Br J Urol. 1994 Oct;74(4):444-6.
Laboratory findings • Leukocytosis; immature neutrophils may reach 40 to 50% • Elevated serum creatinine • Myoglobinuria and hemoglobinuria (due to toxin induced hemolysis) • hypoalbuminemia, hypocalcemia • Positive blood culture (60%) • Elevated serum creatinine kinase
Antibiotic therapy • The most compelling justification: prevent complications • Beta-lactams + Clindamycin: have a favorable outcome --Pediatr Infect Dis J 1999; 18:1096. • Before culture proved: Clindamycin + carbapenem or penicillin plus beta-lactamase inhibitor • Diagnosis is established: penicillin G + Clindamycin
Antibiotic therapy • Eagle effect: failure to response to penicillin owing to slowly growing organisms • Severe scarlet fever, streptococcal bacteremia, pneumonia, meningitis, deep soft tissue infection, STSS Max. dose: 0.4MU/kg/24 hr