Soft tissue and bone infection

Question 1

who does acute osteomyelitis mostly effect?

Answer 1

children, boys>girls, hx of trauma and other diseases (dm, rheum arthristis, sickle cell)

Question 2

what is the source of infeciton of osteomyelitis?

Answer 2

haematogenous spread (children and elderly), local spread from trauma, bone surgery or joint replacement.

Question 3

give some examples of sources of infeciton?

Answer 3

in infants: infected umbilical cord, in children: boils, tonsilitis, skin abrasions, in adults: UTI, arterial line.

Question 4

whhat are the most common effecting organisms of osteomyelitis?

Answer 4

staph.a, strepB, ecoli, strep pyogenes, H.influenzae, mycobacterium tuberculosis, proteus.

Question 5

what other ordgainisms commonly cause osteomyelitis?

Answer 5

sickle cells (salmonella), dm foot (anarobes), fishermen (myco. Marinum), HIV (candida).

Question 6

what is the pathology of osteomyelitis?

Answer 6

starts at the metaphysis, then there is vascular stasis, acute inflammation causing increased pressure, suppuaration thhen release of pressure. Then necrosis of the bone (sequestrum), new bone formation (involucrum), then some resolution.

Question 7

what bones does it mainly effect?

Answer 7

distal femur, proximal tibia, proximal humerus, hip, elbow. (long bones metaphysis or joints with intra-articular metaphysis)

Question 8

what are the clinical features

Answer 8

infant - failure to thrive, metaphyseal tenderness and swelling, common at knee
child - pain, reluctance to move, fever and tachycardia, malaise, toxaemia.
Adult - commonly seen in the thoracolumbar spine, backache, hx of uti, elderly dm, immunocompromised. secondary OM more common, after open fracture or surgery, mixture of organisms.

Question 9

Ix of OM

Answer 9

fbc, WBC, ESR, CRP, blood cultures, tissue swabs, uande’s, Xray, US, aspiration, isotope bone scan, labelled white cell scan, MRI.

Question 10

what are the diff dx’s for OM?

Answer 10

acute spetic arthritis, inflammatory arthritis, trauma, transient synovitis, soft tissue infection (cellulitis, erysipelas, necrotising fascitis, gas gangrene, toxic shock syndrome).

Question 11

what do the radiographs of OM show?

Answer 11

periosteal changes, medullary changes (lytic areas), late osteonecrosis (sequestrum), late periosteal new bone (involucrum).

Question 12

Tx of OM?

Answer 12

supportive, splinatage, Antibiotics (fluclox and benzylpen), surgery.

Question 13

complications of acute osteomyelitis

Answer 13

septacemia, metastatic infection, pathological fractures, septic arthritis, altered boine growth.

Question 14

what is te route of infection of acute septic arthritis?

Answer 14

haematogenous, eruption of bone abscess, direct invasion.

Question 15

organisms which commonly cause septic arthritis

Answer 15

staphh.a, haemophilus influenzae, strep.pyogenes, e.coli.

Question 16

whats the pathology of septic arthritis?

Answer 16

acute synovitis with purulent joint effusion. The articular cartilage is attacked by bacterial toixn and cellular enzyme. There is complete destruction of the articular cartilage

Question 17

what are the clinical features of septic arthhritis?

Answer 17

neonate - picture of septicaemia (irritability, resistance to movement, ill)
child/adult - acute pain in a single large joint (reluctant to move any joint) increased temp and pulse, increased tenderness.
Adult - superficial joint (knee, ankle, wrist).
HOT, RED, SWOLLEN, TENDER, FEBRILE, HYPOTENSIVE,

Question 18

Ix of SA?

Answer 18

fbc, wbc, esr, crp, blood cultures, xray, us, aspiration.

Question 19

whats the most common cause of septic arthritis in an adult?

Answer 19

infected joint replacement

Question 20

differential diagnosis of SA?

Answer 20

acute osteomyelytis, trauma, irritable joint, haemophilia, rheumatic fever, gout, Gauchers disease.

Question 21

Mx of SA?

Answer 21

supportive, abx, surgical drainage and lavage.
After blood cultures and joint aspiration - iv antibiotics, (fluclox, vanc if methicillin resistant, iv fluids, arthoscopic washout (surgical drainage and lavage).

Question 22

what are the types of tuberculosis effect of bone and joint?

Answer 22

extra and intra-articular and vertebral body.

Question 23

clincical features of TB infection on the bone?

Answer 23

incidious onset, pain, swelling, pyrexia, ankylosis, deformity

Question 24

patology of tb

Answer 24

Usually spinal (little pain, present with abscess or kyphosis). primary complex (in the lung or gut), secondary spread, tuberculous granuloma. Role of nutritiona dn oter dieseases.

Question 25

what are the diagnostic factors of tuberculosis?

Answer 25

Long history, involvement of a single joint, thinckening of the synovium, muscle wasting, periarticular osteoporosis.

Question 26

Ix of TB?

Answer 26

fbc, esr, mantoux test, sputum/ urine culture, xray, joint aspiration and biopsy.

Question 27

what does the xray of the bone show? What does the aspiration show? - in TB infection

Answer 27

soft tissue swelling, periarticular osteopaenia, articular space narrowing/ AAFB in 10% or culture +ve in 50%

Question 28

differential diagnosis of tb?

Answer 28

transient synovitis, monoarticular RA, haemorrhagic artheritis, pyogenic arthritis, tunour.

Question 29

Tx of TB?

Answer 29

chemo (rifampicin, isoniazid, ethambutol for 8 weeks THEN rifampicin and isoniazid for 6-12 months)