Infections of Bones and Joints Flashcards
What is osteomyelitis?
It is inflammation of the bone usually due to infection
What are the different sources from which you can get osteomyelitis?
Haematogenous route:
Infection resulting from haematological bacterial seeding from a remote source.
Direct route:
Infection occurs where there is direct contact of infected tissue with bone - as may occur during a surgical procedure or following trauma.
What are the risk factors for osteomyelitis?
- Trauma (orthopaedic surgery or open fracture).
- Prosthetic orthopaedic device.
- Diabetic foot disease.
- Peripheral arterial disease.
- Chronic joint disease.
- Immunosupression (alcoholics, long term steroids etc)
How does acute osteomyelitis present?
- Painful, tender, erythematous immobile limb.
- Continuous pain
- Febrile, maliase, swelling
Note: In diabetics neuropathy may mask pain
How does chronic osteomyelitis present?
A variety of the following:
- Previous acute infection
- Localised bone pain +/- decreased ROM
- Erythema and swelling over the affected area.
- Non-healing ulcer.
- Draining sinus tracts.
- General fatigue/malaise
What are your differentials for osteomyelitis/ Septic arrhtiris?
Cellulitis. Septic arthiritis Crystal arthropathy Trauma Monoarticular presentation of RA/CTD Reactive arthritis
How should you investigate suspected osteomyelitis?
Normal bloods:
FBC/U/E’s/LFT’s
CRP
Blood cultures (usually there is a bacteraemia)
Imaging:
Xray (may show osteopenic changes in chronic osteomyelitis)
MRI (better modality in acute)
How should you treat osteomyleitis?
Extensive surgical cleaning and removal of infected implants.
4-6 weeks of antibiotic treatment (12 weeks chronic)
What is septic arthritis?
Infection of a joint space. It is a surgical emergency carrying a significant mortality 10%.
What is the usual source of infection in septic arthritis?
It is usually caused by a haematogenous spread either from the skin or from an URTI.
What are the common organisms which cause septic arthritis and osteomyelitis?
Staph aureus is the most common.
In IVDU’s gram -ve’s are important to consider.
In sexually active adults dissemniated gonoccocal infection is an important cause.
Which joints are usually affected in septic arthritis?
It can affect any joint, more commonly it affects the knee and hip joint.
Note: affects the clavicular sternal joint, very few things cause pain at this joint therefore if there is pain here have a high suspicion.
How does septic arthritis usually present?
It usually presents with an acute/subacute mono arthritis:
- Very painful joint.
- Pain worse on movement.
- Very swollen and red.
Systemic symptoms of infection:
- Fever and rigors
- May be shocked
What are the essential investigations in septic arthritis?
Joint aspiration: aspirate being sent for urgent gram stain and culture.
Blood cultures.
Swabs from around the wound if skin inflammed
Other bloods: CRP, ESR, U+E, uric acid (gout), clotting
If gonoccocal suspected a genital tract swab is needed as gonoccocal septic arthritis is less likely to grow from joint aspirate culture.
How should you manage a patient with septic arthritis?
A-E
Resus and analgesia. (sepsis 6)
May need splint for pain relief
IV antibiotics* (flucloxacillin is started emperically until cultures can guide management)
Joint aspiration.
Early agressive physiotherapy to avoid stiffness.
*Course is usually 2-3 weeks IV followed by 6 weeks oral although this is guided by ESR/CRP results.
