Q:
What are the layers of skin (from out to in)?

A:
* Keratinised outer epithelium
* Epidermis
* Dermis
* Sucutaneous fat and lumphatics
* Fascia
* Muscle

Q:
What are the three main genera of dermatophyte fungi?

A:
* Epidermophyton
* Trichophyton
* Microsporum

Q:
What are the characteristic lesions associated with dermatophyte fungi?

A:
Scaly lesions with raised edges and a red and itchy centre.

Q:
What are the 2 main types of mycobacterium to cause skin infections?

A:
* Mycobacterium leprae (leprosy)
* Mycobacterium marinarum

Q:
What is the correct treatment of ischaemic ulcers?

A:
Always cleaning and debridement. In severe infections - IV antibiotics. In minor infections - oral antibiotics. 
Metronidazole and (cephalosporin or penicillin/clavulanate).

Q:
What are the important organisms causing infection in burn injuries?

A:
* P. aeruginosa
* S. aureus

Q:
What are the important organisms causing infection in bite injuries?

A:
* S. aureus
* Streptococci
* Oral anaerobes
* Pasteurella multocida
* Clostridia

Q:
What are the important organisms causing infection via percutaneous catheters?

A:
Skin flora such as S. epidermidimis, S. aureus, E. coli and othe enteric organisms.

Q:
What are the important organisms causing infection in water associated injuries?

A:
* Pseudomonas aeruginosa
* Vibrio. Spp
* Mycobacterium marinuarum

Q:
What are the spreading infections of the skin?

A:
* Impetigo (epidermis)
* Erysipelas (dermis, dermal lymphatics)
* Cellulitis (several layers of skin and subcutaneous fat)

Q:
What is the organism most commonly responsible for boils and carbuncles?

A:
S. aureus.

Q:
What are the virulence factors of Staph. aureus?

A:
* Multiple pore forming toxins
* Coagulase (causes host to lay down fibrin wall)
* Catalase
* Hyaluronidase (breaks down hyalorunic acid and help spread through connective tissue)
* Protein A (causes antibodies to bind the wrong way around)
* Lipases, proteases, DNAses (destroy components of host cells)
* B-Lactamase (resistance to B-Lactam antibiotics)

Q:
What are the organisms most commonly responsible for erysipelas?

A:
Strep. pyogenes, can be a co-infection with Staph. aureus.

Q:
How do you treat erysipelas?

A:
Usually treat the Strep. pyogenes with a penecillin, cloxacillin if Staph. aureus co-infection.

Q:
What are the organisms most commonly responsible for cellulitis?

A:
Strep. pyogenes, can be a co-infection with Staph. aureus.

Q:
How do you treat cellulitis?

A:
Usually treat with a penecillin and flucloxacillin. Treatment should cover both Staph. and Strep. because cellultis spreads so quickly. A minor injury can progress to septicaemia in 24 to 48 hours.

Q:
How do you treat cellulitis in a patient with a penecillin allergy?

A:
Erythromycin and cephalosporin.

Q:
What is the prognosis for necrotising fasciitis?

A:
Infection spreads extremely rapidly along fascial planes. 60-80% mortality. 

Q:
What is the treatment for necrotising infections?

A:
They require aggressive treatment. 
* Surgical removal of devitalised tissue
* Systemic antibiotics to cover both aerobes and anareobes

Q:
What organism is usually responsible for gas gangrene?

A:
Clostridium perfringens.

Q:
What is another name for Lockjaw?

A:
Tetanus.

Q:
What is the symptom opisthotonos (seen in tetanus)?

A:
A tetanic spasm causing arching of the back, where the body rests of the head and heels.

Q:
What is the symptom risus sardonicus (seen in tetanus)?

A:
A clenched jaw grimace.

Q:
What is the most common causitive organism of osteomyelitis?

A:
Staphylococcus aureus.

Q:
Ture or false? In children with osteomyelitis less than 5 years old, not immunised to HiB you should treat with cefotaxime or ceftriaxone.

A:
True.