Theme 10 L3: Clinical infections - orthopaedic, skin and soft tissue

Question 1

Which microorganisms colonise the skin?

Answer 1

• coagulase-negative staphyloccoci
• S.aureus
• propionibacterium
• cornyebacterium spp

Question 2

What are viral warts?

Answer 2

small asymptomatic growths of skin (hands, genitals, feet, around nails, throat)

Question 3

What is the causative agent of viral warts?

Answer 3

HPV

Question 4

Explain the pathogenesis of viral warts

Answer 4

proliferation and thickening of stratum corneum, granulosum and spinosum

Question 5

What is the treatment of viral warts/

Answer 5

topical - salicyclic acid, silver nitrate, cryosurgery

Question 6

How do we prevent viral warts?

Answer 6

gardasil (types 16, 18, 6 and 11) and genital: barrier protection

Question 7

What is a pilonidal cyst or abscesss?

Answer 7

• cysts or abscesses in natal cleft
• contain hair and debris
• present with pain, swelling, pus

Question 8

What is impetigo?

Answer 8

• crusting, around nares and corners of mouth
• superficial skin
• transmissible

Question 9

What is the causative organism for impetigo?

Answer 9

staph aureus

Question 10

What is erisipelas?

Answer 10

• raised and demarcated rash over face

- upper epidermis

Question 11

What is the causative organism of erisipelas?

Answer 11

strep pyogenes

Question 12

What similar condition is more severe than erysipelas?

Answer 12

cellulitis

Question 13

What is cellulitis?

Answer 13

infection affecting the inner layers of the skin - dermis and subcutaenous fat, into lymphatics

Question 14

What are some causative agent?

Answer 14

bacterial - S.aureus, group A strep, other B-haemolytic streptococci

Question 15

How does cellulitis develop?

Answer 15

• bugs enter through breaks in skin
• wound, insect bite
• pre-existing condition e.g eczema, athletes foot

Question 16

What is the clinical presentation of cellulitis?

Answer 16

• Rubour (red), calor (heat), dolor (pain), tumor (swelling)

* Loss of skin creases, blistering, pus/exudate, fever

Question 17

What is orbital cellulitis?

Answer 17

infection of soft tissues around and behind eye

Question 18

what is the clinical presentation of orbital cellulitis?

Answer 18

erythema, swelling with induration and pain on eye moveemnt, bulging

Question 19

What are the causes of orbital cellulitis?

Answer 19

S.aureus, S.pyogenes

Question 20

How do we treat orbital cellulitis?

Answer 20

iV antibiotics

Question 21

What are the 4 types of necrotising fasciitis?

Answer 21

Type 1: synergitis/ poly-microbial
Type 2: Group A strep (s.pyogenese mediated)
Type 3: Vibrio vulnificus
Type 4: Fungal

Question 22

Explain the pathogenesis of type I necrotising fasciitis?

Answer 22

ischamic tissue, colonisation then infection resulting in further ischaemia and necrosis

Question 23

Explain the pathogenesis of type II necrotising fasciitis?

Answer 23

infection, toxin release - disruption in blood supply - necrosis

Question 24

What is the clinical presentation of necrotising fasciitis?

Answer 24

swelling, erythema, pain

, crepitus , sepsis, necrosis

Question 25

What is gangrene?

Answer 25

necrosis caused by inadequate blood supplyq

Question 26

What are the causes of gangrene?

Answer 26

atherosclerosis
smoking
DM
autoimmune

Question 27

What are the three types of gangrene?

Answer 27

1. Dry gangrene - “mummified”
2. Wet gangrene - exudate, surrounding erythema, swollen (dactylitis)
3. Gas gangrene - crepitus

Question 28

Explain the pathogenesis of gangrene

Answer 28

poor blood flow 
tissue necrosis
colonisation
infection
synergistic infection
further necrosis

Question 29

What is diabetic foot infection?

Answer 29

spectrum of disease from superficial through to deep bone infection in patients with diabetes

Question 30

Explain the pathogenesis of diabetic foot infection

Answer 30

• Damage to blood vessels – ischaemia, impaired immunity and poor wound healing
• Damage to nerves – neuropathy, trauma
• High blood sugars – prone to bacterial infection

Question 31

What are the causative organisms of diabetic foot infection?

Answer 31

superficial - skin flora: S.aureus, streps, corynebacterium

deeper - skin and enteric flora: above + GNB, anaerobes

Question 32

How do we treat diabetic foot infection?

Answer 32

• Surgical debridement
• Revascularisation
• Antibiotics
• Off-loading
• Diabetic control

Question 33

What is osteomylelitis?

Answer 33

infection of bone

Question 34

What is the difference between acute vs chronic osteomyelitis?

Answer 34

Acute: associated with inflammatory reaction, fulminant, sepsis
Chronic: present for > 1 month

Question 35

What is the clinical presentation of osteomyelitis?

Answer 35

acute pain, swelling, erythema, sinus, pathological fracture,

Question 36

What is septic (or pyogenic) arthritis?

Answer 36

infection of the joint (usually bacterial but can also be caused by viruses, mycobacterium and fungi)

Question 37

What is a prosthetic joint infection?

Answer 37

“PERI” prosthetic joint infection - infection of tissue and bone surrounding a prosthetic joint

Question 38

How would a patient with prosthetic joint infection present?

Answer 38

pain, instability, swelling/ erythema, sinus formation - pus

Question 39

What is syphilis caused by?

Answer 39

treponema pallidum - a spirochete

Question 40

What is the treatment for syphilis?

Answer 40

penicillin

Question 41

What are the 3 stages of syphilis?

Answer 41

1. Primary
   - painless, firm non-itchy ulcer (chancre)
   - at point of contact
   - lasts 3-6 weeks
   - lymphadenopathy
2. Secondary
   - 4-10 weeks after ulcer (chancre)
   - symmetrical, red/pink, non-itchy rash
   - everywhere including soles, palms, mucous membranes
   - maculopapular or pustular rash that contains treponema
3. Tertiary
   - 3 to 15 years after initial infection

Question 42

What are the 3 forms of tertiary syphillis?

Answer 42

1. Gummatous (late benign) - granulomatous lesions affecting mainly liver and bone
2. Neuro
3. Cardiovascular