Bone and soft tissue infections

Question 1

What are the most common bone and soft tissue infections?

Answer 1

Osteomyeltis
Septic athritis
TB infection

Question 2

What is osteomyeltis?

Who typically gets it?

Answer 2

Infection within the bone itself, can be acute or chronic

Tends to effect children, boys more than girls.There can be a history of trauma and the individual may have co-morbidities such as diabetes, rheumatoid arrthritis, immune compromisation, long term steroid treatment and sickle cell

Question 3

How does one develop a osteomyeltic infection?

Answer 3

Can spread through the bone or bloood. Can spread from a contagous site of infection, open fracture, bone surgery or joint replacement. Can also occur secondary to vascular insufficiency

Question 4

What are the common sites of infection?

Answer 4

Umbilical cord- infants
Boils, tonsillitis, skin abrasions- children
UTI, arterial line- adults

Question 5

What are the common organisms that cause osteomyeltis?

Answer 5

Infants:staph auresu, grou b strep, e.coli
Older children:staph aureus, strep pyogenes, flu
Adults:staph aureus, coag negative staphlococci, pseudomonas aeroginosa

Question 6

What rare organisms may cause osteomyeltis in certain subpopulations?

Answer 6

Diabetic foot and pressure sores: mixed infection including anaerobes
Sickle cell: salmonella spp
Fishermen, fileters: myocobacterium marinum
Immunoinsufficiency, AIDS: Candida

Question 7

Where is osteomyeltis typically found?

Answer 7

Long bones e.g. distal femur, proximal tibia, proximal humerus.

Joints with intra-articular metaphysis: hip, elbow

Question 8

What are the clinical features of osteomyeltis in infants?

Answer 8

May be minimal signs or may be very ill
Failure to thrive
Possible drowsy or irritable
Metaphyseal tenderness and swelling
Decreased range of movement
Positional change
Most common around the knee

Question 9

What are the clinical features of osteomyeltis in children

Answer 9

Severe pain
Reluctant to move
May be tender, fever, swinging pyrexia and tachycardia
malaise (fatigue, nausea, vomiting)
toxaemia (degraded bacterial enzymes in the blood)

Question 10

What are the clinical features of osteomyeltis in adults?

Answer 10

Primary OM seen in thoracolumbar spine
backache
history of UTI or urological procedure
elderly, diabetic, immunocompromised

Question 11

What are the clinical features of secondary osteomyeletis in adults

Answer 11

Secondary OM much more common

often after open fracture, surgery especiialy ORIF

Question 12

How do you diagnose osteomyeltis?

Answer 12

History and clinical examination (pulse and temp)
FBC and WBC, ESR, CRP
Blood culturesx3 at peak ofswinging pyrexia
U&Es

Question 13

What are some differential diagnosis for osteomyeltis

Answer 13

acute spetic athritis
acute inflammatoy arthritsi
trauma
transient synovitis
cellulitis
necrotising fascitis
toxic shock syndrome

Question 14

What imaging procedures would be carried out for soemone suspected to have osteomyeletis

Answer 14

X0ray
Ultrasound
Aspiration
Isotope bone scan
labelled white cell scan
MRI

Question 15

What is seen in an x-ray of someone with osteomyeltsi?

Answer 15

no change first two weeks
10-20 days periosteal change
Late osteonecrosis
late periosteal new bone

Question 16

How would you diagnose osteomyeltis with micbiology

Answer 16

Blood cultures
Bone biopsy
Tissue or swabs from 5 sites around prosthetic joints
Superifical swaps of skin may be misleading

Question 17

How do you treat osteomyeltis

Answer 17

Rest and splintage, empiracal antibioticcs (fluclox and benzylepen) while waiting for blood cultures

Question 18

Why may antibiotics fail in osteomyeltis

Answer 18

Drug resistance, MRSA
Dormant bacteria in dead bone
poor host defence
poor drug absorbtion
poor tissue penetration

Question 19

What are the surgical indications for osteomyeltis

Answer 19

Aspirtions of pus for diagnosis and culture.
Abscess drainage
Debridmen of dead/infected/ contaminated tissue
infected joint replacement

Question 20

What are the complications of osteomyeltis

Answer 20

Septicemia, death, metastatic infection, septic athrtits, altered bone growth, chronic osteomyelitis

Question 21

What causes osteomyetis pathology

Answer 21

Cavities, sinuses
dead bone
involucrum
chronic inflammation

Question 22

What causes chronic ostemyeltis?

Answer 22

Often mixed infection
usually same organism each flare up
typically staph aureus, e coli, strep pyogenes

Question 23

What is the treatment of chronic osteomyeltis

Answer 23

Long term antibiotics
Eradicate bone infection
Treat soft tissue problems
Reconstruction
Amputation

Question 24

What is septic athritis?

Answer 24

Infection of a joint that causes athritis

Question 25

How does septic athritis occur?

Answer 25

carried in the blood Eruption of a bone abscess Direct invasion- penetrating wound, iatrogenic, joint infection, intra-articular injury, arthroscopy

Question 26

What organsims cause septic athritis?

Answer 26

Staph.aureus flu strep. pyogenes e. coli

Question 27

What happens during septic athritis

Answer 27

Acute synovitis with pruelnt joint effusion Articular cartilage attacked by bacterial toxin and cellular enzyem complete destruction of the articular cartilage

Question 28

What may occur after septic atrhitis?

Answer 28

Complete recovery Partial loss of articular cartilage and therfore OA Fibrous or bony ankylosis

Question 29

Describe how septic athritis presents in an neonate

Answer 29

Like septicaemia iiritable resistant to movement ill

Question 30

How does septic athritis occur in a child

Answer 30

``` Acute pain ina single large joint reluctant to movethe joint reduced range of movement Increased temperature and pulse increased tenderness ```

Question 31

How does septic athritis occur in an adult?

Answer 31

Often involves superificial joint (knee, ankle, wrist) Rare in healthy adult May be a delayed diagnosis

Question 32

What investigations are carried out if septic athritis is suspected

Answer 32

FBC, WBCM ESR, CRP, blood cultures X-ray Ultrasound Aspiration

Question 33

What are the differential diagnosis for septic arthritis?

Answer 33

``` Acute osteomyeltis Trauma irratibel joint haemophilia rheumantic fever gout gauchers disease ```

Question 34

What is the treatment of septic athritis

Answer 34

Generally supportive mesures antibiotics for 3-4 weeks surgical drainge and lavage- never let the sun set on pus Infected joint replacement

Question 35

Describe a TB infection of the bone

Answer 35

Can be extra-articular (epiphyseal, bones with haemodynamic marrow) Intra-articular (large joints) Vertebral body Multiple lesions in 1/3 of patients

Question 36

What are the clinical signs of a TB infection of the bone

Answer 36

``` Insidious onset and general ill health Pain (at night), swelling, loss of weight low grade pyreaxia joint swelling decreased range of movement ankylosis deformitiy Contact with TB ```

Question 37

Describe the presentation of TB in the spine

Answer 37

Little pain | present with abscess or kyphosis

Question 38

How do you diagnose TB infection from an examination

Answer 38

``` Long history Involvemnt of signle joint Marked thickening of synovium marked muscle wasting periarticular osteoperosis ```

Question 39

TB investigations

Answer 39

FBC, ESR, Mantoux test, sputum/urine culture X ray- soft tissue swelling, preiarticular osteopaenia, articular space narrowing Joint aspiration and biopsy AAFB indeitified in 10-20%

Question 40

What is the differential of TB

Answer 40

``` Transient synovitis Monoarticular RA Haeorrhagic athritis Pyogenic arthritis Tumour ```

Question 41

What is the treatment of TB

Answer 41

Rifampicin Isoniazid Ethambutol for 8 weeks Rifampcina dn isoniazid for 6-12 months rest and splint operative drainage rarely necessary