Bone and Soft Tissue Infections Flashcards
Acute osteomyelitis is most common in which groups?
Children
Boys
History of tumour
What conditions are associated with Acute osteomyelitis?
Diabetes Rheumatoid Arthritis Immunocompromisation Long-term steroids Sickle cell
What are the sources of infection in Acute osteomyelitis?
Haematogenous spread
Spread from contiguous site of infection
Vascular insufficiency
What are the most common sources of spread infection in Acute osteomyelitis in children?
Boils
Tonsillitis
Skin abrasions
What are the most common sources of spread infection in Acute osteomyelitis in infants?
Infected umbilical cord
What are the most common sources of spread infection in Acute osteomyelitis in adults?
UTI
Arterial line
What is the most common organism infant acute osteomyelitis?
Staph aureus
Group B strep
E. coli
What is the most common organism childhood acute osteomyelitis?
Staph aureus
Strep pyogenes
Haemaphilius influenza
What is the most common organism adult acute osteomyelitis?
STAPH AUREUS
TB
Pseudomonas aeroginosa
Coag -ve staph
Propionibacterium spp
What organisms are associated with prosthetic acute osteomyelitis?
Coag -ve staphylococci
Propionibacterium spp
What organisms are associated with acute osteomyelitis due to penetrating foot injuries, IVDA?
Pseudomonas aeroginosa
What organisms are associated with acute osteomyelitis with diabetes?
Mixed - including anaerobes
What organisms are associated with acute osteomyelitis with sickle cell disease?
Salmonella spp.
What organisms are associated with acute osteomyelitis with fishermen?
Mycobacterium marinum
What organisms are associated with acute osteomyelitis with Immunosuppression?
Candida
Which part of the bone is typically affected in Acute Osteomyelitis of long bones?
Metaphysis:
Distal femur
Proximal tibia
Proximal humerus
Which part of the bone is typically affected in Acute Osteomyelitis of joints with intra-articular metaphysis?
Hip
Elbow (radial head)
What is the pathological process of acute osteomyelitis?
Metaphysis - vascular stasis Acute inflammation Suppuration Release of pressure Necrosis of bones (sequestrum) New bone formation (involcrum) Resolution or progression to chronic
What are the clinical features of Acute Osteomyelitis in infants?
Minimal --> very ill Failure to thrive Drowsy/irritable Metaphyseal tenderness/swelling Decreased ROM Positional change
Where isAcute Osteomyelitis most common in infants?
Knee
What are the clinical features of Acute Osteomyelitis in children?
Severe pain Reluctant to move Not weight bearing Tender fever + tachycardia Malaise Toxaemia
What are the clinical features of Acute Osteomyelitis in adults?
Backache
UTI/urological procedure
Where is primary acute osteomyelitis most common in adults?
Thoracolumbar spine
How is acute osteomyelitis diagnosed?
History + exam FBC + WBC ESR + CRP Blood cultures x3 (at peak temp) U+E X-ray, USS Aspirate Isotope bone scan White cell scanW
What DDx is associated with acute osteomyelitis?
Soft tissue infection Acute Septic Arthritis Acute Inflammatory Arthritis Trauma Transient Synovitis
What rare DDx is associated with acute osteomyelitis?
Sickle cell crisis
Gaucher’s disease
Rheumatic fever
Haemophilia
What is sequestrum?
Late osteonecrosis
What is involucrum?
Late periosteal new bone formation
How does acute osteomyelitis present radiologically?
Early - minimal change 10-20days - periosteal changes Medullary changes Lytic areas Osteonecrosis New bone
Which scans are used in acute osteomyelitis?
Technetium 99
Gallium 67 citrate
Indium-111 (WBC scan)
MRI
How is microbiology used in Acute Osteomyelitis?
Blood cultures in septic arthritis/haematogenous infection
Bone biopsy
Tissue swabs 5 sites
Why are sinus tracts no use in Acute Osteomyelitis diagnosis?
Contamination with skin commensals
How is Acute Osteomyelitis treated?
Supportive
Rest + splintage
Antibiotics (IV/oral switch 7-10 days) - 4-6 weeks
Surgery
Why are antibiotics weak in treating Acute Osteomyelitis?
Drug resistance
Bacterial persistence
Poor host defences
Poor drug absorption
What are the indications for surgery in Acute Osteomyelitis?
Aspiration of pus for Dx
Abscess drainage
Debridement
Infected joint replacements
What complications are associated with Acute Osteomyelitis?
Septicaemia, death Metastatic infection Pathological fracture Septic arthritis Altered bone growth Chronic osteomyelitis
What are the causes of Chronic Osteomyelitis?
Acute osteomyelitis De novo: - Operation - Immunosuppression, diabetes, etc Repeated wound breakdown
Which organisms are associated with Chronic Osteomyelitis?
Mixed Same each flare-up Staph. aureus E. coli Strep. pyogenes Proteus
What complications are associated with Chronic Osteomyelitis?
Chronic pus discharge Metastatic infection Pathological fracture Growth disturbance Squamous cell carcinoma
How is Chronic Osteomyelitis treated?
Antibiotics (local/systemic) Surgical Treat soft tissue problems Correct deformity Amputation
What is the route of infection of Acute Septic Arthritis?
Haematogenous
Eruption of bone abscesses
Direct invasion
Which are the common organisms in Acute Septic Arthritis?
Staph aureus
H. influenzae
Strep pyogenes
E. coli
What is the pathological process of Acute Septic Arthritis?
Acute synovitis with purulent effusion
Articular cartilage attacked by bacterial toxin
Destruction of cartilage
What sequelae are associated with Acute Septic Arthritis?
Complete recovery
Partial loss of articular cartilage - osteoarthritis
Fibrous/bony ankylosis
How does Acute Septic Arthritis present in neonates?
(Septicaemia)
Irritability
Resistant to movement
Illness
How does Acute Septic Arthritis present in children?
Pain in single large joint
Reluctant to move
Raised temp + pulse
Tenderness
How does Acute Septic Arthritis present in adults?
Superficial joint
How is Acute Septic Arthritis investigated?
FBC, WBC ESR, CRP Blood cultures X-ray Ultrasound Aspiration
What is the most common cause os septic arthritis in adults?
Infected joint replacement
What is the differential diagnosis of Acute Septic Arthritis?
Acute ostemyelitis Trauma Irritable joint Haemophilia Rheumatic fever Gout Gaucher's disease
How is Acute Septic Arthritis treated?
Supportive
Antibiotics 3-4 weeks
Surgical drainage & lavage
What is the classification of bone/joint TB?
Vertebral body (most common) Extra-articular (epiphyseal bones) Intra-articular (large joints)
How does bone/joint TB typically present?
Multiple lesions Insidious onset Pain/swelling/weight loss Low grade pyrexia Joint swelling Decreased ROM Ankylosis
How does spinal TB present?
Little pain
Abscess
Kyphosis
How is bone/joint TB diagnosed?
Long history Single joint involved Synovium thickening Marked muscle wasting Periarticular osteoporosis
How is bone/joint TB investigated?
FBC, ESR Mantoux test Sputum/urine culture X-ray Joint aspiration and biopsy
How does bone/joint TB present on X-ray?
Soft tissue swelling
Periarticular osteopaenia
Articular space narrowing
What DDx is associated with bone/joint TB?
Transient synovitis Monoarticular RA Haemorrhagic arthritis Pyogenic arthritis Tumour
How is Tuberculosis treated?
Isoniazid Rifampicin Ethambutol (8 weeks) Rifampicin + Isoniazid (12 months) Rest and splintage Operative drainage (rare)
