bone, joint and soft tissue

Question 1

skin/skin structure infections (SSSIs) diagnosis

Answer 1

staphylococcus aureus - gold, grapes (gram positive coccus) catalase positive
streptococcus pyogenes - chains of gram positive coccus. catalse negative. fever causing.

Question 2

staphylococcus aureus virulence factors

Answer 2

catalse positive 
coagulase
hyaluronidase 
protein A
haemolysins
lipase 
protease

Question 3

streptococcus pyogenes virulence factors

Answer 3

lancefield group A
capsule
adhesins
hyaluroniase
haemolysins
anti-opsonic factor

Question 4

skin environment

Answer 4

dry, sheds
low pH
sebacious secretions 
lyzosyme
resident competition

Question 5

Folliculitis

Answer 5

infection of hair folicle
staph aureus - pus - WBCs, neutrophils
pseudemonas aeruginosa

Question 6

Furuncle

Answer 6

deeper penetration

single folicle

Question 7

carbuncle

Answer 7

collection of furuncles connected subcutaneously
extends into subcutaneous fat - below dermis
bacteraemia

Question 8

Impetigo

Answer 8

superficial skin infection - layers of subcorneal keratinocytes
staph aureus - golden scabs
highly infectious, common in men - high contact sport

Question 9

staphylococcal scalded skin syndrome

Answer 9

babies/children
staph aureus secretes exfoliative toxin
breaks down desomosomes between granulosum and spinosum
mortality in adults opportunistic infection- electrolyte imbalace

Question 10

erysipelas

Answer 10

superficial form of celulitis - infection of dermis
red lesions
group A strep (pyogenes)

Question 11

cellulitis

Answer 11

rapidly spreading infection of skin, fat and underlying tissue
septacaemia
not raised
caused by break on skin
S. aureus, P aeruginosa, enterobactericae
anarobes - forniers gangrene

Question 12

surgical wound infections

Answer 12

S aureus

antibiotic prophalyxasis used in bowel and orthopeadic surgery to prevent

Question 13

necrotising fascitis

Answer 13

rare 
flesh eating 
infects soft tissues (fascia)
inflammation, tissue necrosis 
quick spread, extreme pain
group A strep

Question 14

gangrene

Answer 14

infection of deep tissue 
loss of blood supply
loss of O2 - anaerobes 
clostridium species 
smelly

Question 15

gas gangrene

Answer 15

clostridium perfringens
alpha toxin - phospholipase damages membrane
rapid metabolism = gas observed
rapid spread = 12 minute doubling time

Question 16

anthrax

Answer 16

bacillus anthraxis - gram positive
spore forming
cutaneous - ulcerative skin lesions

Question 17

Rickettsia infection

Answer 17

Rickettsia species
obligate intracellular parasite 
transmitted by fleas
Typhus - 
epidemic - skin rash - typhoid fever 
endemic - Rickettsia Typhi
rocky mountain spotted fever - Rickettsia Ricketsi

Question 18

bite infections

Answer 18

humans - worst - Eikenella corrodens

Question 19

lyme disease

Answer 19

spirochete - Botellia Burgorferi
target shaped rash. fever, muscle pain
transmitted via tick

Question 20

osteomyelitis

Answer 20

infection of the bone
due to haemetogenous spread 
inoculation during surgery 
pain/swelling 
hyperdense on x ray 
staph and strep - long bones 
M tuberculosis and T pallidum - spine 
kingella kingae - pelvis 
difficult to treat - antibiotics cannot penetrate

Question 21

septic arthritis

Answer 21

staph aureus 
strep pyogenes capsule similar to hyaluronic acid 
salmonella enterica 
haemophillus influenzae
N. ghonorrhea
hypomobility, warmth
sinobial fluid taken as sample

Question 22

dental cari

Answer 22

polymicrobial
strep mutans 
actinomyces - ludvigs angina 
HSV 
oral thrush
cause osteomyelitis