osteomyelitis/septic arthritis

what is septic arthritis

infection of joint

route of infection in septic arthritis

haematogenous

eruption of bone abscess

direct invasion

• penetrating wound

• joint injection

• inrta-articular injury

• arthroscopy

pathology of septic arthritis

acute synovitis with purulent joint effusion

articular cartilage attacked by bacterial toxin and  cellular enzymes

complete destruction of the articular cartilage

presentation of septic arthritis

Acute pain in single large joint

Reluctant to move the joint

any movement – c.f. bursitis where RoM OK

Swelling – seen in superficial joint

NOT erythema – unless superficial joint and late sign

increase temp. and pulse

increase tenderness

most common bacteria causing septic arthritis

S. aureus

differential diagnoses of septic arthritis

acute osteomyelitis

trauma

irritable joint

haemophilia

rheumatic fever

gout

Gaucher’s disease

diagnosis of septic arthritis

joint aspiration - done before starting antibiotics

first line antibiotics for septic arthritis

flucloxacillin

- penicillin allergy = clindamycin

- vancomycin if MRSA suspected

treatment of septic arthritis

General supportive measures

Urgent Surgical drainage & lavage - emergency

  open or arthroscopic lavage

Appropriate antibiotics (3-4 weeks)

 Infected joint replacements

infected joint replacements for septic arthritis

DAIR, One stage revision,

Two stage revision, antibiotics only

why do adults get infected joint replacement in septic arthritis and what is the organism involved

Recurrent operation

Removal arthroplasty

Amputation

Death

changing picture of organisms, but Staph epidermidis/aureus still most common

TB in bone and joint

•extra-articular (epiphyseal / bones with haemodynamic marrow)

•intra-articular (large joints)

•vertebral body

multiple lesions

minimal pain

progressive deformity

clinical features of TB

insidious onset & general ill health

contact with TB

pain (esp. at night), swelling, loss of weight

low grade pyrexia

joint swelling

decrease ROM

ankylosis

Progressive deformity

pathology of TB

primary complex (in the lung or the gut)

secondary spread

tuberculous granuloma

HIV/AIDS

TB diagnosis

long history

involvement of single joint

marked thickening of the synovium

marked muscle wasting

periarticular osteoporosis

investigation for TB

FBC , ESR

Mantoux test

Sputum/ urine culture

Xray

• soft tissue swelling

• periarticular osteopaenia

• articular space narrowing

Joint aspiration and biopsy

•  AAFB identified in 10-20%

• culture +ve in 50% of cases

TB treatment

initial: 8 weeks

• rifampicin

• isoniazid

• ethambutol

follow on rifampicin and isoniazid 6-12 months

rest and splintage

operative drainage/fusion

what is osteomyelitis

infection of bone and bone marrow

where in the bone does osteomyelitis typically occur

metaphysis

most common bacteria causing osteomyelitis

Staphylococcus aureus

acute osteomyelitis has what?

no bony change

where is acute osteomyelitis typically seen in adults

thoracolumbar spine

age specific organisms in acute osteomyelitis

<1 year:

• staph aureus

• group B streptococci

• E.coli

< 4year:

• kingella kingae

older children:

• staph aureus

• strep pyogenes

• haemophilus influenzae

in acute OM where is pseudomonas aeruginosa commonly seen in

IV drug users or penetrating foot injuries

in acute osteomyelitis, coagulase negative staphylococci associated with

prostheses

where does acute ostemyelitis happen? - pathology

long bones - metaphysis

• distal femure

• proximal tibia

• proximal humerus

joints with intra-articular metaphysis

• hip

• elbow (radial head)

who does acute osteomyelitis typically affect?

most children

boys > girls

risk factors for osteomyelitis

bots and children under age of 10

open bon fracture

ortho surgery

immunosuppression

sickle cell

HIV

TB

source of infection for acute osteomyelitis

haematogenous spread

local spread - contiguous site of infection - open fracture, bond surgery, joint replacement

secondary to vascular insufficiency

infants = infected umbilical cord

children = boils, tonsillitis, skin abrasions

adults = UTI, arterial line, chest, gallbladder

clinical features of OM in infants

minimal signs or very ill

failure to thrive

drowsy

irritable

not feeling

pseudoparalysis

decreased ROM

positional change

-commonest around knees and often multiple sites

clinical features of OM in children

severe pain

reluctant to move

• neighbouring joints held flexed

• not weight bearing

• may be tender

fever - swinging pyrexia

malaise

toxaemia

clinical features of OM in adults

backache - unremitting and at rest

history of UTI or urological procedure

elderly

diabetic

immunocompromised

when is secondary OM more common

open fracture, surgery

mixture of organims

-in adults

how is acute OM diagnosed

history and clinical examination

- pulse and temperature

FBC

WBC (neutrophil leucocytosis)

ESR, CRP

blood cultures x3 at peak temperature

U&E's - patient often dehydrated

X-ray

microbiology

isotope bone scan (tc-99 gallium-67)

labelled white cell scan (indium-111)

MRI

when do you do an X-ray for suspected OM and why

after 2 weeks as they are normal for 10-14 days

function of ultrasound as a diagnostic technique

for sub-periosteal collection

microbiological diagnosis of OM

blood cultures

bone/periosteal biopsy

differential diagnoses of acute OM

cellulitis - strep A

acute septic arthritis

trauma - fracture, dislocation

acute inflammatory arthritis

transient synovitis (irritable hip)

rare:

sickle cell

• Gaucher's disease

• rheumatic fever

• haemophilia

acute OM treatment

supportive

- pain relief, rehydration

- rest and splintage

antibiotics

surgery but rare

antibiotics regime and options for acute OM

IV then switch to oral 7-10 days

- duration 4-6 weeks

choices

- empirical - flucloxacillin, benzyl penicillin

why can’t you give ciprofloxacin to kids

quinolone antibiotic that causes problems with growth and tendon damage

indications for surgery in acute OM

aspiration of pus for diagnosis and culture is needed

abscess drainage is needed

debridement of dead/infected or contaminated tissue

refractory to non-operative treatment >24-48 hours

acute OM complications

metastatic infection

chronic OM

pathological fracture

septic arthritis

septicaemia

death

altered bone growth

risk factors for chronic OM

follow on after acute OM

operation

open fracture

immunosuppression

diabetes

elderly

drug abusers

repeated breakdown of healed wounds

causative organisms for chronic OM

mixture

- staph aureus

- E. coli

- strep pyogenes

- proteus

pathology of chronic OM

cavities

sequestrum (necrotic bone)

involucrum (new bone formation)

histology shows chronic inflammation

treatment of chronic OM

long term antibiotics

• local - gentamicin

• systemic - oral or IV

eradicate bone infection via surgery

treat soft tissue problems

correction of deformity

reconstruction

amputation last resort

complications of chronic OM

chronically discharging sinus + flare ups

ongoing metastatic infection and abscesses

pathological fracture

growth disturbance and deformities

marjolin’s ulcer - squamous cell carcinoma