CP10-4 Clinical Infections Orthopaedic, Skin And Soft Tissue Flashcards
What is the function of skin?
Physical barrier
Homeostasis including thermoregulation
Immunological function
What type of bacteria colonises the skin?
Coagulase+negative staphylococci
What are viral warts?
Small asymptomatic growths of skin on hands, genitals, feet, around nails and/or throat due to HPV virus causing proliferation and thickening of stratum cornerman, granulosum and spinosum
How do clinical warts present?
How are viral warts treated?
Topically with salicylic acid, silver nitrate and with cryosurgery
How can viral warts be prevented?
gardasil
barrier protection (to protect against genital warts)
What are pilonidal cysts or abscesses?
Cysts or abscesses in natal cleft potentially caused by in growing hair. They contain hair and debris and can discharge to form a sinus.
How do pilonidal cysts present?
How are pilonidal cysts treated?
What is impetigo?
A superficial skin infection caused by staph aureus which causes crusting around nares or corners of the mouth.
How is impetigo treated?
What is erysipelas?
An infection affecting the upper dermis, which can involve the lymphatic system, causing a rash over the face which is raised and demarcated. It is caused by strep pyogenes (strep Aj.
How is erysipelas treated?
What is cellulitis?
Infection affecting the inner layers of the skin including the dermis and subcutaneous fat, into lymphatics, due to staph aureus or strep pyogenese.
How do patients with cellulitis present?
How are patients diagnosed with cellulitis?
How are patients with cellulitis treated?
With elevation, rest, antibiotics and source control e.g. drainage of pus.
What is orbital cellulitis?
An infection of soft tissues around and behind the eye which develops from infection in the skin, or sinuses or blood, or can be caused by trauma.
How do patients with orbital cellulitis present?
What are causative organisms of orbital cellulitis?
Staph aureus
Strep pyogenes
Strep pneumoniae
Haemophilus influenza
How is orbital cellulitis treated?
With IV antibiotics
What is necrotising fasciitis?
A rapidly progressive, life threatening infection which tracks along the fascia and causes necrosis which cuts of blood supply.
What are the four types of necrotising fasciitis?
Type 1: synergistic/poly-microbial infection in older people caused by gram negative staph, strep and anaerobes, affecting impaired hosts e.g. by diabetes mellitus, immunosupression etc…
What is an example of type 1 necrotising fasciitis?
Fournier gangrene
What is the pathogenesis of type 1 necrotising fasciitis?
What is the pathogenesis of type 2 necrotising fasciitis?
How do patients with necrotising fasciitis present?
swelling
erythema
pain
crepitus
sepsis/toxaemia
necrosis of tissue with “dish water” exudate
How is necrotising fasciitis treated?
Is a surgical emergency requiring debridement and antibiotics
What is gangrene?
Necrosis caused by inadequate blood supply separated into dry, wet or gas gangrene.
What are risk factors for gangrene?
Atherosclerosis, smoking, diabetes mellitus and auto-immune disease
What is the pathogenesis of gangrene?
Poor blood flow = tissue necrosis = colonisation = infection = synergistic infection = further necrosis
How do patients present with dry vs wet vs gas gangrene?
Dry = mummified and auto amputate
Wet =boggy, swollen, dactylitis tissue with exudate and surrounding erythema
Gas = as above but with crepitus due to gas in tissue
What organisms causes gangrene?
How is gangrene treated?
Surgically for source control and revascularisation + antibiotics
What is diabetic foot infection?
A spectrum of diseases from superficial through to deep bone infection in patients with diabetes
What is the pathogenesis of diabetic foot infection?
Damage to blood vessels = ischaemia, impaired immunity and poor wound healing
Damage to nerves = neuropathy and lead to trauma as reduced sensation
High blood sugars =more prone to bacterial infection
What organisms cause diabetic foot infection?
Staph aureus, streps, corynebacterium + GNB and anaerobes can cause deeper infections
How is diabetic foot infection treated?
Surgical debridement and revascularisation
Antibiotics
Off loading
Diabetic control
What is osteomyelitis?
Infection of bone
What is the pathogenesis of osteomyelitis?
Contiguous e.g. diabetic foot infection
Haematogenous e.g. bacteraemia
Penetrating e.g. due to trauma
Infection results in sequestrum (bone death) and new bone formation (involucrum)
How does acute and chronic osteomyelitis differ?
What organisms cause osteomyelitis?
bacteria inc. staph aureus, strep, kingella, salmonella (in people with sickle cell) & haemophilus spp.
How do patients with osteomyelitis present?
With acute pain, swelling, erythema, sinus and pathological fracture
How are patients with osteomyelitis treated?
Antibiotics for 4-6 weeks, especially if haematogenous cause, Surgical debridement and stabilisation of bone if dead bone present
What pathogen can cause osteomyelitis in people with sickle cell?
Salmonella
What is septic (or pyogenic) arthritis?
An infection of the joint via haematogenous infections, local spread from adjacent soft tissue, bone or bursa or due to penetrating injuries like surgery, trauma or joint injections.
What organisms cause septic arthritis?
How to patients with septic arthritis present?
Pain, swelling, erythema, reduced range of movement with inability to weight bear +/- sepsis
How are patients diagnosed with septic arthritis?
From clinical examination with confirmation via joint aspiration
How is septic arthritis treated?
Antibiotics guided by cultures for 4-6 weeks
Surgical source control with a joint washout
What is prosthetic joint infection?
Infection of tissue and bone surrounding a prosthetic joint which occur as bugs get onto an area the immune system cannot reach and establish a biofilm.
What are the two types of prosthetic joint infection and how do they differ?
Early - bugs implanted at time of surgery or shortly after via the wound
Later - haematogenous cause resulting in late presenting infection
What organisms cause prosthetic joint infection?
How do patients with prosthetic joint infection present?
How are patients with prosthetic joint infection treated?
Antibiotics alone (but rarely work)
Antibiotics.+ debridement (also prone to treatment failure)
Single stage revision - infected joint removed and replaced with a new one in same operation
Two stage revision - infected joint removed, 6 weeks of antibiotics then new joint inserted when infection settled (gold standard)
What is syphilis?
An STI caused by treponema pallidum which has three stages of disease - primary, secondary and tertiary. Can also be transmitted vertically.
What is primary syphilis?
What is secondary syphilis?
Occurs 4-10 weeks after chancre and presents as
What is tertiary syphilis?
How is syphilis treated?
With penicillin
