Orthopaedic infections Flashcards
What is osteomyelitis?
Infection of bone including compact and spongy bone as well as the bone marrow
What kind of infection is involved in osteomyelitis?
Mostly bacterial
Occasionally fungal
What are the causes of the bone infection in osteomyelitis?
Trauma
Haematogenous spread
What is the name given to a dead fragment of bone?
Sequestrum
Which patients are most prone to development of osteomyelitis?
Young
Old
Immunocompromised patients
Those with chronic disease
Why is the infection in osteomyelitis difficult to eradicate?
Leucocytes release enzymes which cause osteolysis, forming pus which impairs the blood supply
What is an involucrum?
A growth of new bone that forms around a mass of dead or infected bone
What in the bony anatomy of children can result in bacterial accumulation within the bones?
In children, the metaphyses of long bones contain abundant tortuous vessels with sluggish flow which can result in accumulation of bacteria and infection spreads towards the epiphysis
In which patients might osteomyelitis co-exist with septic arthritis and why?
In neonates and infants, certain metaphyses are intra‐articular including the proximal femur, proximal humerus, radial head and ankle and infection can spread into the joint causing co‐ existent septic arthritis
Why might an abscess form in the subperiosteal space in osteomyelitis in infants?
They have a loosely attached periosteum
What is a Brodie’s abscess?
Subacute osteomyelitis in children which results in walling off of an abscess by a thin layer of sclerotic bone
Where does chronic osteomyelitis tend to occur in adults?
Spine or pelvis, due to haematogenous spread from pulmonary or urinary infection, or from discitis
Which causative bacteria is unique to developing osteomyelitis in sickle cell anaemia patients?
Salmonella
What tends to be the causative organisms of osteomyelitis in adults?
Staph. aureus
Streptococcal infections
Enterobacter
What tends to be the causative organisms of osteomyelitis in newborns (<4 months)?
Staph. aureus
Group A & B strep
Enterobacter
What tends to be the causative organisms of osteomyelitis in children? (<4 years)
Staph. aureus
Group A strep
Enterobacter
Haemophilus influenzae
How is acute osteomyelitis managed?
“Best guess” antibiotics
Surgical drainage of any abscess
C&S if infection fails to resolve
How is chronic osteomyelitis managed?
Antibiotics for suppression of symptoms
Surgery for deep bone tissue biopsy
Debridement of any non-viable bone
Stabilisation of bone if necessary
Which patients are at particular risk of osteomyelitis of the spine?
IV drug users
Immunocompromised patients
Patients with poorly controlled diabetes
How might osteomyelitis of the spine present?
(Lumbar spine most commonly affected) Insidious onset back pain - constant and unremitting Paraspinal muscle spasm Spinous tenderness Fever/systemic upset
How does septic arthritis present?
Painful, red, hot, swollen joint
Severe pain on movement
How can a joint become infected?
Infection of adjacent tissues
Haematogenous spread
History of penetrating wound e.g. tooth or rose thorn injury
Following intra-articular surgery
When should endocarditis be considered in a case where the main differential is septic arthritis?
Involvement of more than one joint
Involvement of bone (septic emboli)
What is the most common causal bacteria in septic arthritis in adults?
Staphylococcus aureus
Streptococci
In which patients is E. coli the most common cause of septic arthritis?
IV drug users
Elderly
Seriously ill
What is the most common cause of septic arthritis in young adults?
Neisseria gonorrhoea
What is the first course of action with any joint suspected of septic arthritis?
Aspiration of joint fluid
C&S before antibiotics are given
What is the treatment for confirmed septic arthritis?
Surgical washout
What complications are associated with deep infection of prosthetic joint replacement?
Pain Poor function Recurrent sepsis Chronic discharging sinus formation Implant loosening
What complications are associated with deep infection of fracture fixings and stabilisations?
Chronic osteomyelitis
Non‐union of the fracture
Which organisms tend to cause an early infection of a prosthetic replacement?
Staph. aureus
Gram negative bacilli including coliforms
Which organisms tend to cause an indolent or “low grade” infection which isn’t usually picked up until much later in a prosthetic replacement?
Staph. epidermidis/coagulase negative staphylococci
Enterococcus
Which organisms are associated with much later infection/infection from haematogenous spread of a prosthetic replacement?
Staph. aureus
Beta haemolytic streptococcus
Enterobacter
