《儿科学》课程教学课件（PPT讲稿）25 Scarlet Fever

Scarlet Fever

Scarlet Fever

?Scarlet FeverScarlet fever is an acute respiratory infection口caused by Group A β-hemolytic streptococci(GAS, S. Pyogenes) which produce erythrogenictoxins.Fever,pharyngitis，scarlet maculaeover口ingeneralized erythema, and desquamationconvalescentstage.Immunopathogenic complications, knownas口rheumatic fever or glomerulonephritis, may occur in2 to 3 wk after infection in some cases.DIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY

Scarlet Fever DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY □ Scarlet fever is an acute respiratory infection cau sed by Group A β - hemolytic streptococci (GAS, S. Pyogenes) which produce erythrogenic toxins. □ Fever, generalized pharyngitis, s carlet maculae over erythema, and des quamation in convalescent stage. □ Immunopathogenic complications, known a s rheumatic fever or glomerulonephritis, may occur in 2 to 3 wk after infection in som e cases

?History神馨双天女国场Thomas Sydenham叶天士(YeTian Shi)(1624-1689)（166)745"the ShakespeareofMedicine"First clinical described and named in清代，叶天士有较详细记述，中1675inhistorybySydenham.医称为“烂喉痧”（LanHouSha）DIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY

His t o r y Thomas Sydenham (1624-1689) "the Shakespeare of Medicine" Firstclinicaldescribed and n a m e d in 1675 in historyby Sydenham. 清代，叶天士有较详细记述，中 医称为“烂喉痧”(Lan Hou Sha) 叶天士(YeTian Shi) (1666-1745) DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY

?Scarlet FeverStreptococciThe gram-positive cocci that grow in pairsor variable-lengthchainsDIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY

The gram-positive cocci that grow in pairs or variable-length chains DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Scarlet Fever Streptococ ci

?Scarlet Fever Classification of Streptococci Virulence of Group Aβ-hemolytic streptococciEpidemiology Pathophysiology Clinical Manifestations Complications Lab studiesDiagnosis &DifferentialDiagnosis Treatment PrognosisDIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY

□ Classification of Streptococci □ Virulence of Group A β - hemolytic streptococci □ Epidemiology □ Pathophysiology □ Clinical Manifestations □ Complications □ Lab studies □ Diagnosis & Differential Diagnosis □ Treatment □ Prognosis DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Scarlet Fever

?Scarlet FeverClassificationof Streptococci Virulence ofGroup Aβ-hemolytic streptococciEpidemiology Pathophysiology Clinical Manifestations ComplicationsLab studiesDiagnosis &DifferentialDiagnosis TreatmentPrognosisDIVISIONOFINFECTIOUS DISEASE ANDGASTROENTEROLOGY

Scarlet Fever DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY □ Classification of Streptococci □ Virulence of Group A β - hemolytic streptococci □ Epidemiology □ Pathophysiology □ Clinical Manifestations □ Complications □ Lab studies □ Diagnosis & Differential Diagnosis □ Treatment □ Prognosis

Classification of the GenusStreptococcusComplete Hemolysisβ- hemolytic streptococciPartially Hemolysis:α- hemolytic streptococci No hemolysis:Blood Agar- hemolytic streptococciDIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY

□ C o m p l e t e H e m o l ys i s : β- hemolytic streptococci □ P a r t i a l l y H e m o l ys i s : α- hemolytic streptococci □ No h e m o l ys i s : γ- hemolytic streptococci Classification of the Genus Streptococcus DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY

Classification ofthe Genus Streptococcus8O3二中alphabetagammaDifferent hemolyticreactionsComplete hemolysis =betahemolysinsproduce a clear, yellowzonealphahemolysinsproduceagreenPartial hemolysis =discolorationzoneNo hemolysis=nohemolysins,nozoneDIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY

Classification of the Genus Streptococcus Differ en t h e m o l y t i c r e a c t i o n s C o m p l e t e h e m o l ys i s = beta hemolysins produce a clear,yellow zone DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY P art i a l h e m o l ys i s = N o h e m o l ys i s = alpha hemolysins produce a green discolorationzone no hemolysins, no zone

Classification of the Genus StreptococcusStreptococciβComplete Hemolysisβ- hemolytic streptococciPartially Hemolysisα- hemolytic streptococci1Nonhemolysis-hemolytic streptococciThe β- hemolytic streptococci is the most importantbecause it is one of the major etiologic pathogen of humanDIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY

Classification of the Genus Streptococcus S t r e p t o c o c c i C o m p l e t e H e m o l ys i s β- hemolytic streptococci P ar t ially H e m o l ys i s α- hemolytic streptococci N o n h e m o l ys i s γ- hemolytic streptococci The β- hemolytic streptococci is the mos t important b eca u se it is on e of the major etiologic p a th ogen of h u ma n DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY

Furtherclassification ofβ?hemolytic streptococcicapsuleGroup-specificcarbohydrateprotein antigensβ- hemolyticcarbohydratesstreptococciarepeptidoglycandividedinto 20cell coatgroupscytoplasmalphabetically:AtoHcell wallKto VSketch Map of Structureof StreptococciGroup A(StreptococcusPyogenesS. PyogenesDIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY

Further classification of β- hemolytic streptococci β- hemolytic streptococci are divided into 20 groups alphabetically: A t o H K t o V G r o u p A (Streptococcus Pyogenes) S. Pyogenes Group-specific carbohydrate DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY