Infections of Bones and Joints Flashcards
What are the Newman Definition of Septic Arthritis
1 of 4 points must be met;
- Isolation of pathological agent from infected joint.
- In context of joint suspicious of sepsis, pathogen must be isolated from another source.
- Typical clinical features and turbid joint fluid in presence of antibiotic treatment.
- Post-mortum/pathological features sus of septic arthritis
What is the typical presentation of Septic Arthritis
1/2 week history of a red, painful, restricted joint. Typically involved are large joints, most common are Knee, Hip and Lumbosacral spine
What are predisposing conditions for septic arthritis?
Rheumatoid arthritis or osteoarthritis, joint prosthesis, intravenous drug abuse, alcoholism, diabetes, previous intra-articular corticosteroid injection and cutaneous ulcers.
Name three causative organisms for septic arthritis
Staphylococcus aureus, Streptococcus pyogenes, Staphylcoccus epidermidis. Also don’t forget Neisseria gonorrhoeae.
How can an infection be introduced into a joint?
Haematogenous spread or direct inoculation
What are some of the investigations for septic arthritis?
Aspiration from an area of clean skin (looking at joint fluid), peripheral blood cultures, obtain relevant cultures, X-ray the joint.
What is the management of septic arthritis?
Discuss with othopaedics for washout or if complicated discuss with infectious disease
What is the classic triad for reactive arthritis
Conjunctivitis, urethritis and arthritis
What are the dermatological manifestations of reactive arthritis
Keratoderma Blennorrhagicum, circinate balanitis, ulcerative vulvitis, nail changes and oral lesions
What are the common causative organism for reactive arthritis
Chlamydia trachomatis and campylobacter
How can reactive arthritis be treated?
Full dose NAIDS with gastric protection and treatment of precipitating factors (eg, chlamydia)
What is osteomyelitis
Inflammation of the bone and bone marrow usually caused by pyogenic bacteria, and rarely by mycobacteria or fungi.
How do bones become infected?
Haematogenous spread, local spread, compound fracture and foreign body
Name some examples of foreign bodies that can cause bone infections
Trauma, Sharpnel/GSW, ortho implant, nail through trainer (because of pseudomonas through the trainer)
What are the consequences of septic arthritis
With delayed treatment it can lead to irreversible joint damage, and the case-fatality is approx 11-50%.
What makes you predisposed to osteomyelitis
Sick cell anaemia (salmonella), Travel/milk (brucella), prosthesis (S. epidermis), children under the age of 5 (H. influenzae), UTI (E.coli)
Describe features of haematogenous spread of infection to bones
Usually asymptomatic, skin sepsis may be present and organisms can settle in growing metaphysis near the growth plate.
What are the main organisms that cause osteomyelitis
Staphylococcus Aureus (over 80%) and S.pyogenes (5%). TB can also cause it and gram neg bac
What are the signs and symptoms of osteomyelitis
Painful, swollen site, Fever, reduced movement, paraplegia (loss of sensation and movement in lower limbs)
What are the preliminary investigations for osteomyelitis
If patient has fever, their WBC and their ESR and CRP.
What sort of imaging can you use for osteomyelitis and what will you see?
You can use X-rays but MRI and bone scans are more sensitive. You will see periosteal elevation, focal osteopenia, cortical thinning and scalloping.
What are further investigations of osteomyelitis
Blood culture, Xray, MRI/CT/Bone scan and sample pus. Must take at least three samples in surgery.
What are some primary risk factors for prosthetic joint infection
- Rheumatoid arthritis
- Diabetes Mellitus
- Poor nutrition
- Obesity
What is the main causative organism in prosthetic joint infections and what is the best imaging technique for diagnosis.
Staphylococcus Aureus. Best imaging is Tc bone scan
