Acute Inflammation: Sore Throat

Acute Inflammation: Sore Throat

1. CLINICAL PRESENTATION

   • Streptococcus pyrogenes
   • Gram +ive coccus
   • beta-hemolytic
   • Lancefield Group: A
     • Cell wall polysaccharide: rhamnose + N-acetyl glucosamine

2. BIOLOGICAL NATURE

   • Entry & Spread
     • Found: oro-pharynx + skin
     • Transmission
       • droplet infection
       • hand-mouth contact
       • direct to wound
       • indirect contact with contaminated surface
     • 20% asymptomatic
     • cause small % of sore throat cases
   • Virulence Factors
     • 1. M-protein + Lipoteichoic acid
       • ADHESINS M-protein also reduced complement of attack complexes
     • 2. Erythrogenic toxins A,B,C
       • SUPERANTIGENS activate non-specific T cells -> cytokines
     • 3. Streptolysin O,S
       • HEMOLYSINS CYTOLYSINS
     • 4. DNase
       • breakdown DNA (for nourishment) -> THINS PUS
     • 5. Proteases
       • e.g. C5a - inactivates chemotaxis induced by complement cascade

3. PATHOGENESIS

   • Cell Wall
     • Gram +ive
       • thick peptodiglycan
       • Teichoic + Lipoteichoic acid overlying membrane: ADHESIN
       • Hyaluronic acid capsule: CAMOUFLAGE
     • Gram -ive
       • thin peptidoglycan in periplasm
       • Lipopolysaccharide: SUPERANTIGEN, PAMP
   • Phagocytosis
     • PRR + PAMP -> phagosome -> phagolysosome -> lysis -> release
       • -> induce inflamm mediators
   • Inflammatory Mediators
     • SOURCES
       • Invaders
         • peptidoglycan, lipopolysaccharid
       • Resident cells
         • Macrophage -> TNF, IL-1 Epithelial cells -> IL-8 Mast cells -> Histamine Mitochondria -> NADdehydrogenase All cells -> prostaglandins
       • Acute-phase proteins
         • Mannose-binding lectin (MLB)
     • EFFECTS
       • Complement cascade
       • Bradykinin cascade
       • Coagulation cascade
       • Leaky capillaries
       • Recruitment + activation of PMN
       • Activation of epithelium/endothelium
   • Macrophage
     • 1. Secrete mediators
       • PGE2 LTB4: vasc permeability
       • TNF, IL-1: induce adhesion
       • NAP-2, IL-8: PMN, chemotaxis
     • 2. Blood neutrophils stick to adhesion molecules on endothelial cells -> migrate to chemotactic gradient -> contacted cells activated
   • CLINICAL SYMPTOMS
     • 1. Heat (calor)
       • increased vasc perm -> increased blood flow
     • 2. Redness (rubor)
     • 3. Pain (dolor)
       • Bradykinin cascade
     • 4. Swelling (tumor)
       • leaky capillary -> exudation of plasma pr. + fluid
   • Adhesion
     • Effects on host: no effect, altered morph, invasion, fluid loss + necrosis, apoptosis, cytokine induction

4. DIAGNOSIS +TREATMENT

   • Diagnosis
     • 1. Gram stain
     • 2. Hemolysis test
     • 3. Bacitracin sensitivity
     • 4. Catalase test
     • 4. Phadebact test
   • Treatment: BENZYL PENECILLIN
     • Complications
       • Scarlet fever
       • Rheumatic fever
       • Peritonsillar abcess