MSK- Osteomyelitis Flashcards
What is osteomyelitis?
Infection in bone or bone marrow
Typically affecting metaphysis of long bones by staph aureus
Staph aureus is the commonest cause of osteomyelitis but in which patients is salmonella a common cause?
Sickle cell anaemia
Sickle cell anaemia children - which organism causes osteomyelitis?
Salmonella
Risk factors for osteomyelitis?
Open bone fractures
Orthopaedic surgery
Immunocompromised states
Sickle cell anaemia
HIV
TB
What is septic arthritis?
Septic arthritis is an infection of a joint, most commonly caused by staphylococcus aureus (gram-positive cocci).
The hip is the most commonly affected joint.
What joint is most affected by septic arthritis?
Hip
Symptoms of septic arthritis
High grade fever
Joint pain or limp
Red, hot, swollen joint
What is the criteria for septic arthritis
Kocher’s criteria:
Inability to weight bear.
Fever >38.5ºC.
WCC >12 x 10^9.
ESR >40 mm/hr.
How is septic arthritis diagnosed?
Joint aspiration is the main diagnostic test.
Cultures should be obtained before starting antibiotics.
What is the management of septic arthritis?
Prolonged antibiotics:
IV for 2 weeks, followed by 4 weeks of oral antibiotics.
Joint aspiration to drain and dry the joint (do this before starting antibiotics).
What is reactive arthritis?
Reactive arthritis occurs a few weeks after a GI infection or STI.
It is an HLA-B27 disease.
What are the symptoms of reactive arthritis?
Conjunctivitis.
Urethritis.
Arthritis.
Mnemonic: “Can’t see, can’t pee, can’t climb a tree.”
What is the management of reactive arthritis?
It is typically self-limiting.
Management is focused on symptomatic relief.
What are the clinical features of bone and joint infections (osteomyelitis, septic arthritis)?
Refusing to use the limb or bear weight.
Pain, swelling, and tenderness at the affected site.
What investigations are used to diagnose bone and joint infections?
MRI is the best imaging for diagnosis.
Blood cultures are essential to establish the causative organism.
Take blood cultures before starting antibiotics.
What is the management plan for osteomyelitis?
High-dose IV empirical antibiotics for 2-4 weeks (e.g., flucloxacillin, or clindamycin if allergic).
Switch to oral antibiotics once clinical recovery and normalization of acute-phase reactants (like CRP).
IV to oral transition occurs once CRP normalizes.
Blood cultures should be taken before starting antibiotics.
Surgical debridement of infected bone may be necessary.
