Download MBBS Orthopaedics PPT 13 Osteomyelitis Lecture Notes

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

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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

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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 "

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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)

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Clinical Features

a)

Pain

b) Low grade fever

c)

Mild Redness

d) Mild Tenderness

e)

Discharging sinus

(seropurulent discharge)

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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

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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)

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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.

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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.

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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

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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

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MRI of Osteomyelitis of metatarsal

Decreased signal in T1
weighted images

Appears bright in T2

weighted images.

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Treatment -

? Antibiotics
? Host immunity
? Surgical ? sequestrectomy and debridement

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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.

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This post was last modified on 07 April 2022