Soft Tissue and Bone Infections Flashcards
What 2 things make up soft tissue?
Skin
Connective tissues
Define impetigo
Which bacteria?
Skin infection of the epidermis
Staphylococcal
Define erysipelas
Which bacteria?
Skin infection of the epidermis
Streptococcal
Define cellulitis
Which bacteria?
Skin infection of the dermis +/- subcutaneous fat
Staphylococcal or streptococcal
Define furuncle
Which bacteria?
Deep infection of a hair follicle
Staphylococcal
Define carbuncle
Which bacteria?
Connective collection of furuncles
Staphylococcal
Define necrotising fasciitis
Which bacteria?
Deep infection of the fascia +/- muscle
Streptococcal or mixed
Name some viruses that can infect the skin
Viral warts
Herpes
Viral exanthems (chickenpox, shingles, measles)
Molluscum contagiosum
Smallpox
What organism causes athlete’s foot?
Tinea pedis fungus
What are coagulase-negative Staphylococci?
Staph species that are not staph aureus
Lack an enzyme called coagulase and therefore less aggressive to humans
List the 8 steps of bacterial pathogenesis in SSTIs
Access
Adherence
Invasion
Multiplication
Evasion
Resistance
Damage
Transmission
What 6 things should be used to describe a skin lesion or rash?
Shape
Size
Edge
Colour
Surface
Distribution
How could you tell if someone was infected with a superficial streptococcal?
What infection is this likely to be?
The lesion would be red and well demarcated (obvious border)
Erysipelas
What is cutaneous leishmaniasis?
Parasitic skin infection
Raised wound edge
South America
Name the drug that can be administered in viral skin infections
Aciclovir
chicken pox, herpes, shingles
What is often the first line treatment in MRSA?
Flucloxacillin
What can be given to treat impetigo
Topical fuscidin
What is first line treatment for Streptococcus infections?
Penicillin
e.g. benpen.
What is terbinafine used for?
Topical fungal infections
Can be PO if needed
Define osteomyelitis
Infection of bone
Define septic arthritis
Infection of joints
Define prosthetic joint infection
Infection of an artificial joint replacement
Which microbe is most likely to be responsible for a bone infection?
2nd most likely?
Staphylococcus aureus
Streptococci (B-haemolytic, strep. pneumoniae
List some risk factors for developing a joint or soft tissue infection
Trauma
Medical procedures
Skin ulcers
IV devices, IVDU (haematogenous dissemination)
Immunosuppression - diabetes, renal failure, sickle cell disease
What is a sequestrum?
A part of bone that becomes necrotic due to infection
What is an involucrum?
New bone formation outside the sequestrum
What is the name for a hole in the involucrum that allows pus from the sequestrum to leave the site of infection?
Cloacae
Why can it be hard for Abx and the immune system to penetrate a bone infection?
Because the bacteria sits in an organic matrix across a surface - causes a biofilm
What causes a discharging sinus? How would it present?
Infection and pus from cloacae causes skin necrosis
How might a patient with osteomyelitis present?
Pain
Redness
Swelling
Warmth
Loss of function
Fever
Pathological fractures
Discharging sinuses
How might a patient with septic arthritis present?
Pain
Redness
Swelling
Warmth
Loss of function
Fever
Damage to articular surfaces
What empirical antibiotics would be given for bone infections?
Which bacteria are they best at treating?
IV flucloxacillin
Staphylococcal
IV benzylpenicillin
Streptococcal
