Infections of Bones and Joints Flashcards
What are the main types of bone and joint infections?
Septic arthritis
Osteomyelitis
Reactive arthritis
Prosthetic joint infection (PJI)
What is the most common cause of joint infection in adults?
Staphylococcus aureus
What bacteria commonly cause joint infections in neonates and children?
Neonates: Group B Streptococcus, Gram-negatives
Children: Haemophilus influenzae (rare now), Strep pyogenes
Name some less common organisms that cause joint infections.
Kingella, Salmonella, Brucella, Mycobacterium tuberculosis
What are the main routes of infection in bones and joints?
Haematogenous spread
Direct inoculation (e.g., surgery, trauma)
What is osteomyelitis?
Inflammation of bone and marrow, usually due to infection.
What is the most common organism in osteomyelitis?
Staphylococcus aureus (>80%)
What other organisms may cause osteomyelitis?
Streptococcus pyogenes
Mycobacterium tuberculosis
Gram-negative rods
Salmonella (especially in sickle cell)
What predisposes someone to osteomyelitis?
Sickle cell disease
Orthopaedic implants
UTIs (E. coli)
Immunosuppression
Diabetes
What are typical symptoms of osteomyelitis?
Localised bone pain and swelling
Fever
Reduced movement or function
What are possible complications of chronic osteomyelitis?
Sequestrum (dead bone)
Involucrum (new bone growth around infection)
Persistent sinus tracts
What is septic arthritis?
Infection of a joint, typically bacterial.
What are common symptoms of septic arthritis?
Swollen, red, painful joint
Limited movement
Fever, rigors, sweats
What joints are commonly affected by septic arthritis?
Large joints, especially knees and hips
What is the mortality rate for septic arthritis?
11%–50%, especially high in immunocompromised or elderly patients.
What is the Newman definition for diagnosing septic arthritis?
- Pathogen isolated from joint fluid
- Pathogen isolated elsewhere with clinical joint infection
- Typical signs with turbid fluid
- Pathological or post-mortem evidenc
What is reactive arthritis?
Sterile joint inflammation following an infection elsewhere in the body.
What is the classic triad of Reiter’s syndrome?
Arthritis
Conjunctivitis
Urethritis
What infections are associated with reactive arthritis?
Genitourinary: Chlamydia trachomatis
GI: Shigella, Salmonella, Yersinia, Campylobacter
Others: Clostridium difficile, Borrelia, E. coli
What genetic factor is linked with reactive arthritis?
Keratoderma blennorrhagicum
Circinate balanitis
Nail changes
How is reactive arthritis managed?
NSAIDs (with gastric protection)
Antibiotics if infection persists
