SCARLET FEVER Etiology Epidemiology Pathogenesis and pathology Definition Etiology Epidemiology Pathogenesis and pathology Clinical manifestation Laboratory findings Complications Diagnosis and Different Diagnosis Treatment Prevention

DEFINITION Hemolytic streptococcus B group A Acute respiratory infectious disease Clinical features:Fever ,pharyngitis, genernal diffused fresh red eruption and obvious desquamation Complication:heart,kidney and joints diseases return

Etiology Belong to Group A, Hemolytic streptococcus B Gram(+) 0.6-1.0um in diameter Culture:grow in media contained blood Group:depend on the different somatic polysaccharide Ag in cell wall,the bacteria are divided into 19 group(A-U,no I and J).Group A is major. Serum type:Group A is divided into 80 types according to the protein M on surface. Resistance:weak resistance,sensitive to heat,drying,common disinfectant .Live in sputum and pus for several weeks.

Pathogenic substances 1.LTA (lipoteichoic acid):adherence to epithelial cells. 2.Erythrogenic toxin:fever,rash and others 3.Strptokinase:resolve clot,protect blood from coagulation. 4.Hyaluronidase:extension in tissue,resolve hyaluronid. 5. M protein :toxic to WBC and PLT return

Epidemiology Source of infection patients and carriers pharyngitis—major source Route of transmission air-borne: respiratory tract wound,birth caral-surgical and puerperal type. Susceptability after infection of group A streptococcus, two Ab produce.antibacterial Ab-type specific no cross reaction,antitoxic Ab-five serotype persist no crass reaction

So,reinfection is possible especially pharyngitis Epidemic features 1.season:every season,winter and spiring 2.age: every age,children 3.distribution of district Change of disease

Pathogenesis and pathology Suppurative lesion:local-streptococcus LTA adhere to epithelial cells and go into tissue M protein resists phagocytosis(facilitate) Hyaluronidase,streptokinase and hemolysins result in extension of inflammation and tissue necrosis Toxic lesion:general and organs-erythrogenic toxin erythrogenic toxin and other substances- general toxic symptoms:fever, headache and bad appeptite,

skin:vascular congestion,eruption signs:hepatomegaly and splenomegaly lymphonode fatty degeneration and congestion,myocardia and kidney injury. Allergic lesion:complications myocarditis,myo calves and joints,base membrane of kidney are injured return

Clinical manifestation Incubation period:2-3days(1-7days) Typical type: 1) Fever:39℃,1week 2)Pharyngitis:red exudation sore 3)Rash:24h after fever,diffuse erythema,1mm,pastauricular-neck-chest-limbs 4)companied signs:circumoral pallor,pastia’s lines,raspberry tongue-strawberry tongue. 5)desquqmqtion 6)No pigmentation return

type Septic type Toxic type Surgical or puerperal type Mild type Typical type

Complications Rheumatic fever Glumerulonephritis Arrhritis

Laboratory findings Blood Routine:WBC10-20X109/L,N>80% Urine Rt: protein uria ,cast renal complication Bacteriological examination: swab or secretion-culture Dick test:

Diagnosis and Differential Diagnosis Staphylococcus aureus infection Primary septic site or transmission site or no pharyngitis or pathogen Drug eruption using drug or no pharygitis or relieve after stopping or pathogen Streptococcus mi ti infection sever or liver and kidney injury-shock or pathogen

Treatments General therapy Isolation 7 days, temperature, puls, BP, glucose, liquid Treatment according to symptoms Pathogen therapy penicillin or erythromycin or cefotomycin adult: 5-7d; child: 10d Complications therapy Carrier penicillin 7days

Prevention Control the source of infection isolation patient, treat carriers and pharyngitis for 7 days Interruption of route of transmission mask,disinfect to secrations and infection substances Protect to susceptible populations no vaccine END