Emma best

Question 1

What are two virulence factor for streptococcus pyogenes that helps it resist phagocytosis?

Answer 1

Capsule and M protein

Question 2

What are some other virulence factors for S pyogenes?

Answer 2

M protein
Capsule
Streptolysins -
DNases

Question 3

What are some diseases associated with S pyogenes?

Answer 3

Pharyngitis
Impetigo
Cellulitis
Scarlet fever
Bactericemia
Spetic arthritis
Necrotising faciatis
Toxic shock syndrome
Acute rheumatic fever
Rheumatic heart disease
Post streptococcal glomerulonephritis (Ab:Ag causing renal problems)

Question 4

What are the symptoms of septic arthritis?

Answer 4

Fever, malase
Swelling, redness and tenderness
Joint held in position to maximize volume in joint - flexed leg.

Question 5

Why are children more susceptible to bone and joint infections?

Answer 5

Because they have lots of blood flow to their epiphyseal plates.

Question 6

What are the two most common causes of joint infection?

Answer 6

S aureus first and then S pyogenes

Question 7

What is the treatment for septic arthritis?

Answer 7

Join washout - culture
Intravenous antibiotics - 2 weeks
Then oral antibiotics - 1 week

Question 8

What is the definition of rheumatic heart disease?

Answer 8

Lasting damage to the heart valve (mitral and/or aortic) caused by rheumatic fever

Question 9

What are the jones criteria (rheumatic fever criteria)?

Answer 9

Need 2 major criteria or 1 major and 2 minor criteria. Plus evidece of a past streptococcal infection.

Major:
Carditis
Chorea
Erythema marginatum
Poly-arthritis
Subcutaneous nodules

Minor:
Fever
Polyarthralgia
History of rheumatic fever
Raised CRP or ESR
Prolonged PR interval

Question 10

What do the antibodies do in rheumatic fever?

Answer 10

Cross react with collagen or cardiac valvular endothelia antigens then T cells infiltrate leading to damage.

Auto anti-body mediated neuronal signaling in CSF may cause the chorea.

Question 11

What causes sever damage with rheumatic fever?

Answer 11

Repeated attacks due to strep infections lead to increased scar formation.

Question 12

How can you confirm that someone has had an infection with S pyogenes recently?

Answer 12

Plasma antistreptolysin O (ASO) and anti-DNAase B titres

Question 13

How do you treat rheumatic fever?

Answer 13

Bed rest for 2 weeks
Family members throat swabs
Penicillin intramuscular injections every 4 weeks for 10 years.

Targeting schools in low deprivation areas - throat swabs for all that have sore throat.