The secrets and ideas behind osteomyelitis.ppt

All you have to know about orthopedic osteomyelitis

1. Osteomyelitis

2. Definition
•Osteomyelitisis the infectionof the boneor BMwhich leads to a
subsequent Inflammatoryprocess.
•Micro-Organisms may reach bones via the Bloodstreamor by Direct
Invasion. (e.g: skin puncture, operation, open fracture)
•Factors which affects it’s development
–Virulence of the organism involved
–Host Factors (Age, Immunity, Diseases)
–Local factors (site of Involvement, damaged muscle presence of
foreign material , vascularity)

3. •It can be classified on the basis of the causative organism, the
route, durationand anatomic location of the infection.
•According to duration: acute, subacute, chronic
•In children, osteomyelitismost commonly affects the long bones of
the legs and upper arms.
•Adults are more likely to develop osteomyelitisin the vertebrae.
•Diabetic patients may develop osteomyelitisin their feet if they
have foot ulcers.
•Osteomyelitisusually begins as an acute infection, but it may evolve
into a chronic condition.

4. Acute Osteomyelitis

5. Types
1.HematogenousOsteomyelitis
•Bacterial seeding from the blood.
•Seen primarily in Children.
•The most common site
•Metaphysisat the growing end of LongBones in Children
•Vertebrae in Adults; involving two adjacent vertebrae with
intervertebraldisk (may occur pelvis, long bones and clavicle)
2.DirectInoculation Osteomyelitis
•Its osteomyelitiscomplicating open fracture or surgical
operation, in which organisms gain entry directly through the
wound.
•Tend to involve multiple organisms.but mainly S.Aureus

6. Acute HaematogenousOsteomyelitis

7. Causative Organisms
•Staph. aureus(Most common)
•Strep. pyogensor pneumoniae(Less).
•H.Influenzae(Young Children)
but still, the most common causative organism for osteomyelitisin young
children is staphylococcus aureus
H.flu infection has become less common due to vaccination
•Salmonella (Sickle-Cell)
still, the most common causative organism for osteomyelitisin sickle cell
anemia patient is staphylococcus aureus
Slamonellais the second most common infection in patients withsickle cell
disease

8. Pathology. Organisms reach the bone through the blood stream from a sep-
tic focus elsewhere in the body –for instance from a boil in the skin. In a rare
atypical form in adults infection reaches the vertebral column through the
spinal venous plexus from an infected intrapelviclesion.
In the usual childhood manifestation, the infection begins in the metaphy-
sis of a long bone, which must be presumed to form a productive medium for
bacterial growth (Fig. 7.1A); thence it may spread to involve a large part of the bone. The
organisms induce an acute inflammatory reaction, but the marshalling of the body’s
defensive forces is greatly handicapped in bone because its rigid structure does not allow
swelling. Pus is formed and soon finds its way to the surface of the bone where it forms a
subperiostealabscess (Fig. 7.1B); later the abscess may burst into the soft tissues and may
eventually reach the surface to form a sinus.
Often the blood supply to a part of the bone is cut off by septic thrombosis of
the vessels (Fig. 7.1B). The ischaemicbone dies and eventually separates from
the surrounding living bone as a sequestrum(Fig. 7.1C). Meanwhile new bone
is laid down beneath the stripped-up periosteum, forming an investing layer
known as the involucrum(Fig. 7.1C). The epiphysialcartilage plate is a barrier to the spread of
infection, but if the affected metaphysislies partly within a joint cavity the joint is liable to
become infected (acute pyogenicarthritis). Metaphysesthat lie wholly or partly within a joint
cavity include the upper metaphysisof the humerus, all the metaphysesat the elbow, and
the upper and lower metaphysesof the femur (Fig. 7.2). Even when the joint is not infected it
may swell from an effusion of clear fluid(sympathetic effusion).With efficient treatment, the
infection may be aborted in its earliest phase.Butwhen it has progressed to the stage of
septic thrombosis and death of bone it almost inevitably passes into a state of chronic
osteomyelitis.

10. Pathology
1.Inflammation.
•Earliest Change
•Increase interaosseouspressure leads to Pain.
2.Suppuration
•Pus at medulla >> Volkmann canals>>Surface >> SubperiostealAbscess>>
spread along the shaft>> burst into the soft tissue
•May extend to Epiphysisin Neonates and Children.
•May extend to InterverteberalDiscs in Adults.
3.Necrosis/Sequestrum
•Begin in a week.
•causes : increase in intraosseouspressure, vascular stasis, infected
thrombosis, periostealstripping which increasingly compromise blood
supply

11. 4. New-bone formation
•New bone formation from the stripped surface of periosteum
•Bone thickens to form an involucrumenclosing the infected tissue.
5. Resolution
bone will heal if infection is controlled and intraosseouspressure is
released, though it may remain thickened. orprogress to complications

13. Clinical Features
•Fever , chillsand Malaise
•Pain
•Tenderness, Redness, Edema, Warmth(signs of inflammation)
•Restricted Joint Movement
History preceding Skin Lesion or Sore Throat.
Typically; child, boy. The bones most commonly
affected are the tibia, the femur and the humerus. The onset is rapid. The child
complains of feeling ill, and of severe pain over the affected bone. There may be
a history of recent boils or of a minor injury.
On examination there is pyrexia. Locallythereis exquisite tenderness over the affected bone.
The area of tenderness is clearly circumscribed; it is usually near the end of the bone in the
metaphysialregion. The overlying skin is warmer than normal, and often the soft tissues are
indurated; later a fluctuant abscess may be present. The neighbouringjointis sometimes
distended with clear fluid, but a good range of movementisretained unless the infection has
spread to the joint (septic arthritis)

14. Investigations
1.Lab studies
•CBC: leucocytosis
•Elevated CRP & ESR(nonspecific).
•Blood Culture
•Culture& sensitivity test; by aspiration from the subperiostealabscess,
+vein only 50%of patients with hematogenousosteomyelitis.
2.Radiological studies
•X-ray
•MRI
•Radionuclide bone scanning
•CTscan
•US

15. X-Ray
•1
st
10 days Show No Abnormality .
Only after two or three weeks do visible changes appear, and they may never do
so if efficient treatment is started very early.
•By the end of the 2
nd
Week signs of rarefaction of Metaphysisand
New Bone Formation. Then sigs of healing
•Soft-tissueedemaat 3-5 days after infection.
•Bony changes are not evident for 14-21 days:
–Early radiographic signs of rarefraction(thiningof bony tissue
sufficient to cause decreased density of bone) of the
metaphysisand new bone formation outlining the raised
periosteum
–Sclerosisand thickeningof the bone cortex at healing
•Approximately 40-50% focal bone loss is necessary to cause
detectable lucencyon plain films; a negative X-Ray does not
exclude osteomyelitis

17. Plain-film radiograph showing
osteomyelitisof the 2
nd
metacarpal
•Periostealelevation
•Corticaldisruption
•Medullaryinvolvement.

18. X-ray of the left ankle of a 10-
year-old boy shows:
Lucencyin the tibial
metaphysissecondary to acute
hematogenousosteomyelitis
(AHO).

19. MRI
•Earlydetection and surgical localization of osteomyelitis.
•sensitivity 90-100%
•help to distinguish between Bone and Soft-Tissue Infection.
•now superseded isotope scanning as it provides more
anatomical information on the infection.
MRIsagittalsection shows
the same AHO lesions
with the right lesion
extending into the
growth plate.

20. Radionuclide bone scanning
•A 3-phase bone scan with technetium 99m is probably
the initial imaging modality of choice. VS reserved for
the diagnosis of bone infection in the less clinically
accessible sites such as the hip, pelvis and spine.
•Show increase activity (non specific sign of
inflamation).
Accumulation of isotope depends upon the rate of bone
turnover and its vascuarity, so that in the early stages
of disease inadequate blood supply may result in a
‘cold’ lesion. More commonly, within a few hours or
days of the onset of symptoms there is an increased
uptake of isotope, giving a ‘hot’ scan at the site of the
bone lesion.

21. A.Anterior view B. lateral view
•Both showing the accumulation of radioactive tracer at the
right ankle (arrow). This focalaccumulation is characteristic
of osteomyelitis.

22. CT scan
•Spinal vertebrallesions
•Complex anatomy (pelvis, sternum & calcaneus)
Ultrasound
•In childrenwith acute osteomyelitis.
•May demonstrate early changes, 1-2 days after onset of
symptoms.
•Shows soft tissue abscess, fluid collection & periosteal
elevation.
•Ultrasonographyallows for ultrasound-guided aspiration.
•It does not allow for evaluation of bone cortex.

23. Acute osteomyelitisis to be distinguished from pyogenicarthritisof the
adjacent joint by the following features:
1. the point of greatest tenderness is over the bone rather than the joint
2. a good range of joint movement is retained
3. although the joint may be distended with fluid it does not contain pus
(this may be confirmed by aspiration).

24. Diagnosis
•Criteria(2 of 4):
1.Localized classic physical findings (tenderness, erythema
or edema).
2.Purulentmaterial on aspirationof affected bone.
3.Positive findings of bone tissue or blood culture.
4.Positive radiological imagingstudy.

25. Treatment
1.Analgesia
2.Restof the affected part
3.Antibiotictreatment.
–IVantibiotics for 1-2 weeks then oralfor 3-6 weeks.
–Cultures & sensitivity test.
–systemic antibiotic therapy started intravenously to ensure high blood levels. Initially, it is
recommended that broad-spectrum antibiotics with good anti-Staphylococcus activity are used,
such as a third-generation cephalosporin combined with a synthetic penicillin, but as soon as the
causative organism has been identified the antibiotic to which it is most sensitive should be
ordered. In cases where a multiple-resistant Staphylococcus aureus(MRSA) is suspected it may be
appropriate to use vancomycininstead of the penicillin. Antibiotics should be continued for at least
4 weeks, even when the response has been rapid.
4.Surgery
–Debridement
–Drainageof subperiostealabscess
– Operation may be unnecessary if effective antibiotic treatment can be begun within 24 hours of
the onset of symptoms, but in practice diagnosis is not always so prompt, and in that event it
seems wiser to undertake early operation, in order to release pus and to relieve pain, which is
often severe. This should definitely be performed if there has not been a marked improvement to
the antibiotic treatment within 48 hours.

26. Complications
The important complications are:
1. septicaemiaor pyaemia
2. extension of infection to the adjacent joint with consequent
pyogenicarthritis
3. retardation of growth from damage to the epiphysialcartilage

27. Prevention
•Improve immunity.
•Post-traumatic infection (regular wound dressing for established
infection):
•Debridement of open fractures.
•Stabilization of fractures.
•Antibiotics.
•Closure of exposed bone surfaces.
•Postoperative infection:
•Cleanest possible surgical environment.
•Careful haemostasis.
•Suction drainage.
•Prophylactic antibiotics in high risk surgeries.

28. OsteomyelitisComplicating Open
Fracture Or Surgical Operation

29. •When acute infection complicates open fracture or surgical operation the
organisms are introduced directly through the wound. Any part of the
bone may be affected, depending upon the site of injury.
•Suppuration and necrosis occur as in haematogenousosteomyelitis, but
the pus discharges through the primary wound rather than collecting
under the periosteum.
•The infection often becomes chronic.
•Clinical features:This type of osteomyelitismay occur in children or in
adults.
The temperature fails to settle after the primary treatment of the wound
or rises a few days later. Pain is not a prominent feature because pus is not
contained under pressure. Re-examination of the wound reveals a
purulent discharge.

30. •Radiographic features. In the early stages radiographs do not help
significantly. Later there may be local rarefaction, and eventually
sequestrumformation may be evident.
•Treatment. The main principle of treatment is to secure free drainage
through the wound, which may be enlarged if necessary for the purpose.
Appropriate antibacterial drugs should be ordered. Later, any bone
fragment that has sequestrated should be removed.

31. Chronic Osteomyelitis

32. •Itisnearlyalwaysasequeltoacuteosteomyelitis,generallysecondaryto
openfractures,bacteremiaandcontiguoussofttissueinfection.Itis
difficulttotreatandischaracterizedwithfrequentrelapses
•Occasionallyinfectionissubacuteorchronicfromthebeginning.
•Cause.Aswithacuteosteomyelitis,theStaphylococcusistheusual
causativeorganism,butstreptococci,pneumococci,typhoidbacilli,orother
bacteriamayberesponsible.
•Chronicosteomyelitisfromcontiguoussofttissueinfectionisbecoming
morecommonduetoincreasingprevalenceofdiabeticfootinfectionand
peripheralvasculardisease

33. Pathology
•Itiscommonestinthelongbones.Itisoftenconfinedtooneendof
thebone,butitmayaffectthewholelength.Theboneisthickened
andgenerallydenserthannormal,thoughoftenhoneycombedwith
granulationtissue,fibroustissue,orpus.Sequestra(Fragmentofdead
bone)arecommonlypresentwithincavitiesinthebone.Oftenasinus
tractleadstotheskinsurface:thesinustendstohealandbreakdown
recurrently,butifasequestrumispresentitneverhealspermanently.

35. Clinical features
Non-specificanddifficulttorecognize.Raisesuspicion:
•Persistentsinustract
•Exposedbone
•Tissuenecrosisoverlyingbone
•Chronicwoundoverlyingsurgicalhardware
•Chronicwoundoverlyingfracture
•Mayalsopresentasrecurrentconditionwithperiodsofquiescence,with
exacerbation,patientcomplainingincreasingpainataffectedsite
•apurulentdischarge(themainsymptomisusuallyapurulentdischargefromasinus
overtheaffectedbone.Dischargeofpusmaybecontinuousorintermittent)
•Painmaybethepredominantfeature
•‘flare-up’,or‘flare’,ofinfection(Reappearanceofasinusthathasbeenhealedfor
sometimeanditisheraldedbylocalpain,pyrexia,andtheformationofanabscess)
•Onexaminationtheboneispalpablythickened,andtherearenearlyalwaysa
numberofoverlyingscarsorsinuses.

37. Imaging
•Radiographic examination
–Theboneisoftenthickenedandshowsirregularandpatchysclerosiswhich
maygiveahoneycombedappearance.Ifasequestrumispresentitisseen
asadenseloosefragment,withirregularbutsharplydemarcatededges,
lyingwithinacavityinthebone
•Radioisotope scanning
–increased uptake in the vicinity of the lesion
•MRIand CTscanning
–localisationof abscess cavities and sequestrain diffuse disease, thus
allowing accurate planning of operative treatment.

39. Complications
1.Pathological fracture
2.Rarely, amyloiddisease
3.Rarely, squamouscelled carcinoma in a sinus

40. Treatment
•Surgical debridementand appropriate antibiotictherapy is usually indicated
•rest and antibiotics to subsides an acute flare-up of chronic osteomyelitis.
•If an abscess forms outside the bone it must be drained.
•If there is a persistent and profuse discharge of pus a more extensive
operation is advised. to remove fragments of infected dead bone (sequestra)
and to open up or ‘saucerise’ abscess cavities by chisellingaway the overlying
bone. and to obliterate the cavity.
•The principles of treatment are (1) remove dead and foreign material, (2)
obliterate dead space, (3) if necessary, stabilisethe skeleton, (4) obtain soft
tissue cover, (5) if necessary, reconstruction of the bone defect, (6) possible
appropriate antibiotic cover.

41. SubacuteOsteomyelitis

42. •Results from
–Less virulent Microorganism
–Patientwith an elevated resistance.
•Occurs Mostly at the Distal Femur or Proximal Tibia
•X-Ray we See Brodie’sAbcess:
–Small and Ovalin shape
–It is surroundedby sclerotic bone
–May be mistakenfor OstieoidOsteoma

44. Brodie’sabscess
(chronic bone abscess)

45. •This is a special form of chronic osteomyelitiswhich arises insidiously,
without a preceding acute attack. There is a localisedabscess within the
bone, often near the site of the metaphysis. A deep ‘boring’ pain is the
predominant symptom.
•Imaging; Radiographically, the lesion is seen as a circular or oval cavity
surrounded by a zone of sclerosis ,but the site and extent of the lesion can
be shown more accurately on an MRI scan. The rest of the bone is normal.
•Treatmentis by operation. The cavity is de-roofed and the pus evacuated.
Whenever possible the cavity should be filled with a muscle flap to
obliterate the dead space.

47. Post Operative Infections

48. Post Operative Infections
•Not Uncommon, about a 5% incidence.
•Prophylaxis is KEY in prevention
•Predisposed by:
1.Debility
2.Chronic disease
3.Previous Infection
4.Tight Dressing
5.Corticosteroid Treatment
6.Long Surgery
7.Hematoma
8.Foreign Material Implants