Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Orthopaedics PPT 13 Osteomyelitis Lecture Notes
Osteomyelitis
Department of Orthopaedics
Learning objectives
? Definition
? Aetiology
? Pathogenesis
? Clinical picture
? Investigations
? Differential diagnosis
? Treatment
Definition
? Inflammation of bone
? Osteo= bone ,myelitis = inflammation of marrow
? Rapid destructive pyogenic infection
? Most frequently in infants and children
Aetiology
? Bacterial infection but at times can be fungal infection
? Causes can be ?
1. Diabetes
2. Intravenous drug use
3. Trauma to the part
4. Immunocompromised status of the host.
5. Poor nutrition ,unhygienic surroundings
Aetiology
? Sex: Male /female -4:1
? Location :metaphysis of long bone
due to rich blood supply to that
area
? Hairpin bent of the metaphyseal
vessels
? Metaphyseal hemorrhage
? Defective phagocytosis
? Vasospasm of the end arteries
preventing the antibiotics to reach
there.
Micro-organism
? In Infants : Staphylococcus aureus ,S. agalactiae and E.coli
? In children >1 yr. : Staphylococcal Aureus , Streptococcus pyogenes ,H.
influenzae
? In adults : S.aureus and streptococcus species
? In patients of sickle cell anemia ? salmonella species
CLASSIFICATION
? According to duration of symptoms
Acute (<2 weeks)
Subacute (2-3 weeks)
Chronic (>3 weeks)
Pathophysiology
Mechanism of spread :
? Hematogenous ? MC aetiology in children
? Contiguous spread ?associated with previous surgery ,trauma,
cellulitis
? Direct inoculation ?in penetrating injuries ,open injuries, orthopaedic
surgeries like joint replacement and fixation of fractures.
? Preexisting focus / Exogenous Infection
? Infective embolus enters nutrient artery
? Trapped in a vessel of small Caliber(metaphysis)
? Blocks the vessel
? Active hyperemia + PMN cells exudate
? In order to engulf the bacteria they release
enzymes and lyse the bone around.
? Hyperemia and immobilization causes decalcification.
? Proteolytic enzymes destroy bacteria and medullary
elements.
? The debris increase and intramedullary pressure
increases.
Cont.
? Enter subperiosteal space.
? Strips periosteum.
? Perforation of periosteum / reach joint by piercing capsule.
? Enters soft tissue and may drain out
Clinical presentation
? Severe pain ,malaise ,fever
? Recent history of infection
? Child looks ill and feverish
? temperature raised
? Limb held still and acute tenderness present over the involved limb
? Manipulation of limb painful :pseudo paralysis
? Infants:
Failure to thrive and drowsy
h/o birth difficulties ,umblical
artery catherization or site of
infection
Laboratory investigations
? Elevations in the peripheral white blood cell count (WBC),
? Erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)
? Blood culture is positive in half of cases.
Radiological findings
? Negative for 1st week or 10 days
? Localised area of bone destruction
? Periosteal shadow is elevated
? multiple lamination of bone deposition
? Periosteal new bone formation is seen after 2
weeks.
? Ultrasonography ? juxtacortical soft tissue swelling with periosteal
thickening
? Radionuclide scanning ? sensitive but not specific
increased uptake
? Magnetic resonance imaging ? hypointense on T1 weighted image
hyperintense on T2
Differential diagnosis
? Rheumatic fever : Onset -more gradual,
pain and tenderness less intense.
polyarticular.
Response to salicylates
? Acute suppurative arthritis : Pain and tenderness limited to the joint,
joint movements -restricted
aspiration reveals purulent synovial fluid.
? Ewing's sarcoma : biopsy demonstrates tumor cells
Treatment
? General management-
Rest in bed
Elevation of the part
Systematic treatment- IV fluids, correct shock
Treatment with antibiotics
Surgery
Principles of antibiotic therapy
? Appropriate drug
? Appropriate route
? Appropriate dose
? Appropriate time to stop
? Appropriate adjunctive measures.
Treatment
? Local management
Well timed surgery
Nade's indication for surgery-
? Abscess formation
? Severely ill and moribund child.
? Failure to respond to intravenous antibiotics for more than 48 hours.
Surgical methods
? Aspiration
? Incision and drainage
? Multiple drill holes
? Small bone window
? Bone abscess
? Septic Arthritis
? Septicemia
? Fracture
? Growth arrest
? Overlying soft-tissue cellulitis
? Chronic infection
Subacute osteomyelitis
? insidious onset, mild symptoms, lack of systemic reaction
? Its relative mildness is due to:
Organism being less virulent OR
Patient more resistant OR
(Both)
? Most common site: Distal femur, Proximal & Distal Tibia
Causative organism
? Staphyloccocus aureus (30-60%)
? Others (Streptococcus, Pseudomonas, Haemophilus influenzae)
? Pseudomonas aeruginosa (IV drug user)
? Salmonella (patient with sickle cell anemia)
Radiographic findings
Brodie's abscess
- circumscribed, round/oval cavity containing pus and pieces of dead
bone (sequestra) surrounded by sclerosis.
? MC in tibial / femoral metaphysis.
? May occur in epiphysis / cuboidal bone (eg: calcaneum).
? Metaphyseal lesion cause no / little periosteal reaction.
? Diaphyseal lesion may be associated with periosteal new bone
formation and marked cortical thickening.
Clinical features
? Pain (several weeks / months)
? Limping
? Swelling & Local tenderness
? Muscle wasting
? Body temperature usually normal (no fever)
A circumscribed, oval cavity
This is a lateral view X-ray of left
surrounded by a zone of
tibia and fibula. There is a marked
sclerosis at the proximal
periosteal reaction at the
tibia (Brodie's abscess)
diaphysis.
Investigations
? X-ray (may resemble osteoid osteoma / malignant bone tumor)
? Biopsy
? Fluid aspiration & culture
? ESR raised
? WBC count may be normal
28
Treatment
Conservative :
a)
Immobilization
b) Antibiotics for 6weeks
Surgical (if the diagnosis is in doubt / failed conservative treatment) :
a)
Open biopsy
b) Perform curettage on the lesion
29
BRODIE'S ABSCESS
? Subacute osteomyelitis persist for many years before progressing to
chronic osteomyelitis.
? Classically it is abscess formation surrounded by fibrous tissue or host
tissue.
? Causative organism is staphylococcal aureus in most of the cases.
Presentation
? Localized pain
? Often nocturnal
? Alleviated by aspirin.
location
? Metaphysis of long bones
Upper end of tibia
Lower end of tibia
Lower end of femur
Lower end of fibula
Radiographic findings
Brodie's abscess
- circumscribed, round/oval cavity containing pus and pieces of dead
bone (sequestra) surrounded by sclerosis.
? MC in tibial / femoral metaphysis.
? May occur in epiphysis / cuboidal bone (eg: calcaneum).
? Metaphyseal lesion cause no / little periosteal reaction.
? Diaphyseal lesion may be associated with periosteal new bone
formation and marked cortical thickening.
Radiologically
? Oval, elliptical, or serpentine radiolucency usually greater than 1 cm
surrounded by a heavily reactive sclerosis.
Radiologically
? lytic lesion in the distal
metaphysis with a narrow zone
of transition more caudally
? with a faint sclerotic rim and a
wide zone of transition more
cephalad.
Radiologically
? hyper intense edema in the calf
musculature, marrow edema,
and sub-periosteal pus.
Radiologically
? The thin hypointense rim
surrounding the intramedullary
collection represents the
reactive interface between the
abscess and the body's attempt
to wall it off.
Radiologically
? post gadolinium image showing
the extent of the multiloculated
intramedullary abscess.
Treatment
? In the majority of cases surgery has to be performed.
? If the cavity is small then surgical evacuation and curettage is
performed under antibiotic cover.
? If the cavity is large then the abscess space may need packing
with cancellous bone chips after evacuation.
SALMONELLA OSTEOMYELITIS
? Seen in patient with sickle cell anemia and thalassemia.
? Clinical features ?
Several bones involved
Symmetrical involvement of bones
Severe osteomyelitis
Spine may be involved
Sickle cell anemia present.
Stool may be positive.
Treatment
? The most commonly used antimicrobials are
chloramphenicol,
third generation cephalosporin's
Fluoroquinolones (ciprofloxacin)
In unresponsive cases surgical resection along with prolonged antibiotic therapy needs to be
performed.
Question 1
Chronic Osteomyelitis
? Definition:
" A severe, persistent and incapacitating infection of bone and bone
marrow "
47
Etiological Agents
Usual organisms (with time there is always a mixed infection)
? Staph.aureus(commonest)
? Strep.pyogenes
? E.coli
? Pseudomonas
? Staph.epidermidis (commonest in surgical implant)
48
Clinical Features
a)
Pain
b) Low grade fever
c)
Mild Redness
d) Mild Tenderness
e)
Discharging sinus
(seropurulent discharge)
49
Pathogenesis
Inadequate treatment of acute OM /Foreign implant /
Open fracture
Inflammatory process continues with time
together with persistent infection by infecting organism
Persistent infection in the bone leads to increase in
intramedullary pressure due to inflammatory exudates
(pus)
stripping the periosteum
50
Pathogenesis (Contd.)
Vascular thrombosis
Bone necrosis (Sequestrum formation)
New bone formation occur (Involucrum)
Multiple openings appear in this
involucrum, through which exudates
& debris from the sequestrum pass via
the sinuses
(Sinus formation)
51
Staging Of Osteomyelitis:
? The Cierny-Mader staging system.
? Determined by the status of the disease process.
? It takes into account the state of the bone,
? the patient's overall condition and factors affecting the development of
osteomyelitis.
53
54
Cierny-Mader Classification
? 1: Medullary Osteomyelitis - Infection
confined to medullary cavity.
? 2: Superficial Osteomyelitis -
Contiguous type of infection. Confined
to surface of bone.
? 3: Localized Osteomyelitis - Full-
thickness cortical sequestration which
can easily be removed surgically.
? 4: Diffuse Osteomyelitis -Loss of
bone stability, even after surgical
debridement.
55
Radiographic Findings
1) X-ray examination
-
Usually show bone resorption (patchy loss of density / osteolytic lesion)
-
Thickening & sclerosis around the bone
-
Presence of sequestra
-
Occasionaly it may present as a Brodie's abscess surrounded by vascular tissue and
area of sclerosis
56
2) Radioisotope scintigraphy
-
Sensitive but not specific
-
Technetium labelled hydroxymethylene diphosphonate (99mTc-HDP) may
show increased activity in both perfusion phase and bone phase
3) CT scan & MRI
-
Show the extent of bone destruction, reactive oedema, hidden abscess and
sequestra
57
MRI of Osteomyelitis of metatarsal
Decreased signal in T1
weighted images
Appears bright in T2
weighted images.
58
Treatment -
? Antibiotics
? Host immunity
? Surgical ? sequestrectomy and debridement
59
Complications
1) Pathological Fracture
-
This occurs in the bone weakened by chronic osteomyelitis
2) Deformity
?
In children the focus of osteomyelitis destroys part of the epiphysis growth
plate.
3) Shortening/ lengthening
-
Destruction of growth plate arrest growth.
-
Stimulation of growth plate due to hyperemia.
60
This post was last modified on 07 April 2022