Infection in Bones and Joints Flashcards
Acute osteomyelitis
Infection in bone
Who tends to get acute osteomyeltitis
Children, males
History of disease in acute osteomyelitis
Diabetes, arthritis, immune compromise, long term steroid use, sickle cell anaemia
What is the usual source of infection of acute osteomyelitis
Usually blood borne and tends to be from a local spread of infection.
Usual cause of acute osteomyelitis in infants
Infected umbilical chord
Usual cause of acute osteomyelitis in children
Boils, tonsilitis, skin abrasions
Usual cause of acute osteomyeltitis in adults
UTI or vascular line
Most common organism to cause acute osteomyelitis
Staphylococcus Aureus
Organism cause of acute osteomyelitis in infants
Staph, group B strep and Ecoli
Organism cause of acute osteomyelitis in children
Streptococcus pyogenes and H.influenza
Organism cause of acute osteomyelitis in adults
Staph aureus, coagulase negative strep, strep pyogens
Mixed infection osteomyeleitis tends to occur when
Diabetic foot and pressure sores
Patients with sickle cells disease can get what organism AO
Salmonella
Describe the pathogenesis of Acute Osteomyelitis
The infection starts at the metaphysis resulting in vascular stasis, inflammation, suppuration and then a release of pressure (into the medulla, subperiosteal space of the joint). There is then necrosis of the bone (sequestrum). The bone then tries to heal itself by forming new bone (involcrum). If treatment is started early there can be resolution.
Presentation of Acute Osteomyelitis in infants
Failure to thrive, drowsy and irritable, metaphyseal tenderness and swelling, decreased range of movement in one limb and may be positional change
Presentation of Acute Osteomyelitis in Children
Severe pain, reluctant to move and no bearing of weight, always consider the hip if there is knee pain, fever and tachycardia, there may also be malaise
Presentation of Acute Osteomyelitis in Adults
Often in the back, back pain (keeps the patient awake during the night), history of UTI or urological procedure, elderly, diabetic. Secondary infection (after surgery or open fracture more common)
How is acute osteomyelitis diagnosed
FBC and increase WCC, raised ESR and CRP, three blood cultures taken, U+Es (ill and dehydrated), X-ray (showing metaphyseal destruction after 14 days), US, Aspiration, Isotope bone scan, labelled WCS
Best way to diagnose Acute Osteomyelitis
MRI
State the microbiological tests conducted into Acute Osteomyelitis
Blood culture, bone biopsy, tissue or swabs from up to five sites around implant at debridement in prosthetic infection
How is Acute Osteomyelitis Managed
Analgesia and fluids, rest and splintage, antibiotics for 4-6 weeks (the usual choice being fluxociliin and benzylpenicillin), monitor ESR
Indications for surgical treatment in Acute Osteomyelitis
Aspiration of pus for diagnosis
Abscess drainage
Debridement of dea or infection tissue or bone
Refractory to non-operative treatment >24-48 hours
Complications of acute osteomyelitis
- Septicaemia
- Metastatic infection
- Pathological fracture
- Septic arthritis
- Altered bone growth
- Chronic osteomyelitis
Subacute osteomyelitis
Infection of the bone that occurs in a patient with a good immune system or a bacteria with lowered virulence
Clinical features of subacute osteomyelitis
Longer history, variable symptoms in the pain or lump, localised swelling and tenderness
Brodies Abscness
Subacute osteomyelitis in older children with painful limb and no systemic features
Treatment of subacute osteomyelitis
Curategge and prolonged course of antibiotics
Chronic osteomyelitis clinical features
Has a more slow onset, fever, pain, redness or discharge at the site of infection. May be periods of remission
State the main organisms in chronic osteomyelitis
Staph aureus, E.coli, strep pyogenes, proteus
Pathology of chronic osteomyelitis
Cavitis, sinuses, alongside areas of sequestra.
Treatment of chronic osteomyelitis
Multiple debridement, local and systemic antibiotics (gentamicin cement and oral or IV antibiotics)
Complications of chronic osteomyelitis
Chronically discharging sinus and recurrent flare ups, ongoing infection, pathological fractures, growth disturbances and deformities, squamous cell carcinoma
Acute Septic Arthritis
Inflammation of a joint caused by infection
How does septic arthritis occur
Direct invasion from a penetrating wound, intra-articular injury, arthroscopy, eruption of bone abscesses or haematological spread
State the common causative organisms of septic arthritis
- Staph aureus
- H.influenza
- Strep.pyogens
- E.coli
Pathology of acute septic arthritis
Acute synovitis with purulent joint effusion. The articular cartilage is attakced by bacterial toxin and cellular enzymes resulting in complete destruction of it
Presentation of septic arthritis in neonates
Septicaemia
Presentation of septic arthritis in children
Acute pain in a single largely swollen joint in which the patient is reluctant to move, increased temperature and pulse.
Presentation of septic arthritis in adults
Superficial joint involvement
Investigations of septic arthritis
FBC, WBC, EST, CRP, blood cultures. The X-ray tends to not show very much; ultrasound will show intense effusion within the joint. Aspiration is often helpful in diagnosing the organism responsible.
Treatment of septic arthritis
Antibiotics, surgical drainage and lavage
Clinical Features of bone TB
insidious onset and general ill health, contact with TB, pain, swelling, loss of weight, low grade pyrexia, joint swelling, decreased range of movement, ankyloses and deformity
Spinal TB presentation
Little pain, presents with abscess of kyphosis
Investigation of BONE TB
FBC, ESR, mantoux test, sputum/urine culture. May see changes on X-ray – soft tissue swelling, periarticular osteopaenia and articular space narrowing.
Treatment of bone TB
It tends to involve mainly chemotherapy: rifampicin, isoniazid, ethambutol for 8 weeks then rifampicin and isoniazid for six to twelve months
