BONE AND JOINT
INFECTIONS
Presentation By Dr LEKHRAJ BAIRWA

SUPPURATIVE OR
PYOGENIC
OSTEOMYELITIS

CLASSIFICATION of osteomyelitis
Osteomyelitis is an infection in a bone
1) DURATION:- Acute, Subacute and
Chronic
Suppurative and
Non-Suppurative
2) ORGANISM:-
3) HOST RESPONSE:- Pyogenic and
Granulomatous

• Acute osteomyelitis – present with bone
infection of sudden onset associated with
systemic illness . It develops rapidly over a
period of 7-10 days.
• It can be confirmed from blood culture or
culture from specimen.
• It is easier to treat and overall turns out better
than chronic osteomyelitis.

• Subacute osteomyelitis-insidious in onset ,
symptoms last for more than 2 weeks, no
systemic symptoms .
• Diagnosis of subacute osteomyelitis is difficult
due to absence of obvious signs of local
infection , absence of pyrexia and normal WBC
counts.
• Chronic osteomyelitis- infection had been
present for more than 3 months

CAUSATIVE ORGANISMS
⚫Staphylococcus aureus is responsible for
more than 90% of all bone and joint
infections.
⚫In immunosuppressed patients: H.influenza,
Pneumococcus, Pseudomonas,
Mycobacterium, Fungal & Gram-negative
organisms are more commonly involved.
⚫In neonates: Group B streptococci is a
common cause.

INCIDENCE
• Incidence in US population is 21.8/1lac/year
• Incidence has reduced with the introduction of
antibiotics
• However, there has been an increased risk of
osteomyelitis among Immunosuppressed
patients, newborns, alcoholics and drug
addicts.

VASCULAR ANATOMY
The blood flow through the metaphysis is slow
and turbulent creating a natural environment for
the proliferation of microbes
• INFANTILE PATTERN: The metaphyseal and
diaphyseal vessels penetrate the epiphyseal
plate. Metaphyseal infections can thus pass to
the epiphysis and then the joint.
• CHILDHOOD PATTERN: No metaphyseal blood
vessel penetrates the physis.The metaphysis
is affected in hematogenous osteomyelitis with
sparing of epiphysis and joints.

• ADULT : Metaphyseal vessels penetrate
the vanishing physis & anastomose with
the vessels at the subarticular end of the
bone. This explains increased incidence of
septic arthritis secondary to osteomyelitis
in adults.

INFANTILE CHILDHOOD ADULT
VASCULAR ANATOMY

PATHOPHYSIOLOGY
Four pathways of bone invasion:-
1) Hematogenous spread: Most common source
of infection.
2) Spread from a contiguous source of infection:
Cutaneous, Sinus and Dental infections are
common sites.
3) Direct implantation of infection: Usually
occurs as a result of direct penetrating injuries
or puncture wounds.
4) Postoperative infection: Contamination of
surgical sites.

Implantationof organism in medullary tissue
Vascularand cellular Response
Increased intramedullarypressure
Infarction of Bone Hyperemia
Focal Osteolysis
Penetration of inflammatory process through endosteum &
Haversian canal
Reaches the subperiosteal space
PERIOSTITIS
Loss of blood supply New bone formation
Necrosis INVOLUCRUM
SEQUESTRUM

⚫SEQUESTRUM: Dead bonewhich is denser than
the surrounding bone resulting from the cortical
& medullary infarcts. It is the hallmark of active
infectious process.
⚫INVOLUCRUM: Periosteal new bonewhich is
formed in an attempt to wall off the infective
process.
⚫CLOACAE: are defects in the involucrum which
allow the continued discharge (decompression) of
inflammatory products from the bone. Most
frequently associated with chronicosteomyelitis.

CLINICAL FEATURES of ACUTE
OSTEOMYELITIS
⚫AGE:- 2-12 years
⚫SEX:- Male predominance (3:1)
⚫Fever with chills, pain & swelling over the affected
part and extensive loss of limb function.
⚫Pre-existing infection, most commonly skin,
respiratory tract and genitourinary tract is seen in
50% cases.
⚫Femur is the m/c bone involved. Other common sites
are tibia,humerus & radius.
⚫In adults pelvis and vertebrae are most commonly
affected. In a person with DM bones of feet are
affected, most commonly the calcaneum

IMAGING MODALITIES
• Bone scan and MRI are most sensitive
modalities for detection of osteomyelitis
however conventional radiology should
always be the first imaging modality to start
with as it provides overview of the anatomy
and pathologic conditions of the bone and
soft tissues of the region of the interest.
• Sonography is the most useful in the
diagnosis of fluid collections, periosteal
involvement and surrounding soft tissue
abnormalities.

1) PLAIN RADIOGRAPHS:
 No plain film changes are seen in the early phase of
osteomyelitis.
 Only 5% of radiographs are positive in the early
course of the disease.
 Most accurate means for early detection is a nuclear bone
scan.
 The radiological latent period on a plain film is upto
10 days for extremities and 21 days for spinal
lesions.
 The plain film radiographic diagnosis is made on the
basis of abnormalities of soft tissue and bone.

SOFT TISSUE ALTERATIONS:
⚫Earliest radiographic signs involve the soft tissues
rather than the bone
⚫Seen within 3 days of bacterial contamination of
bone
⚫Swelling of thedeep soft tissues usually around the
metaphysis may be the earliestsign.
⚫Elevation and displacement of fat planes.
⚫Obliteration of fat planes.
⚫Increased density.
⚫Draining sinus.

OSSEOUS ALTERATIONS
⚫BONE DESTRUCTION:
Early lesion is that of a moth-eaten or permeative
destructive pattern usually affecting the metaphysis.
Bone sequestrum formation appears 3-6 weeks after the
initial onset of symptoms.
The necrotic fragments retain their original radiographic
density. As a result, they appear more SCLEROTIC RELATIVE
TO THE ADJACENT OSTEOPENIC BONE.
Large involucrum may be seen which is composed of more
rapidly formed woven bone & is therefore LESS DENSE
RADIOGRAPHICALLY.

⚫PERIOSTEAL RESPONSE:
 Periosteal new bone formation may beof the
following types-
1) Solid
2)Laminated or lamellar pattern
3)Codman’s triangle
 A soft tissue component, subperiosteal abscess
and dense involucrum are more striking in infants
than in adults.

EARLY RADIOGRAPHIC SIGNS.
SOFT TISSUE SWELLING IS SEEN IN HUMERUS ALONGWITH SOLID
PERIOSTEAL REACTION.

A:MOTH EATEN PATTERN
IN DIAMETAPHYSEAL
REGION OF DISTAL
RADIUS WITH SOLID
PERIOSTEAL REACTION
B&C: LYTIC LESION IN THE MEDIAL
METAPHYSIS OF DISTAL FEMUR WITH
PERIOSTEAL RESPONSE ON POSTERIOR
SURFACE OF DISTAL FEMUR.

AP VIEW TIBIAAND FIBULA SHOWING SEQUESTRUM FORMATIONAND
INVOLUCRUM

2) ULTRASONOGRAPHY:
1) Deep soft tissue swelling- earliest sign.
• Periosteal elevation- seen as a hyperechoic line
• Subperiosteal fluid collection.
• Cortical breech- seen as a focal defect in the
cortex.
• Joint effusion
• Abscess or sinus tract formation in soft tissues
which are characteristic of acute osteomyelitis.

Osteomyelitis of tibia showing soft tissue swelling with collection

3) RADIONUCLIDE IMAGING:
• Most sensitive investigation fordetecting early
destructive activity
. Howeverspecificity is low.
• 99mTc-MDP, 99mTc-HMDP and Gallium 67 citrate
are the m/c used radionuclide agents.
• Indium 111 labelled WBC are more sensitive &
specific.
• Theaccretion of radionuclide in bone is related to
the blood flow and local bone turnover.
• On triple phase scans, it shows increased uptake of
“hot spots” on all phases.
• False-positive results are seen in degenerative
disease, healing fracture, soft tissue infection and
loose prosthesis.

• Gallium scan may reveal abnormal
accumulation of radiotracer in patients who
has active osteomyelitis where Tc scan showed
decreased activity or cold lesions
• Gallium accumulation seems to correlate
more accurately with activity of osteomyelitis
than Tc uptake.
• Disadvantage of Gallium can’t distinguish
bone and soft tissue uptake clearly.

Three Phase/Triphasic Bone Scan
The first phase /nuclear angiogram/ flow phase.
• Serial scans are taken during the first 2 to 5 seconds
after injection of the Technetium-99m-MDP. This phase
typically shows perfusion to a lesion.
• Cellulitis shows uptake more in phase 1 and phase 2 scan,
but not in phase 3.
• Pathology that is more moderate to severe will show
more uptake in the first two phases.
• Pathology that is chronic or partially treated will be more
pronounced in the third phase of a triphasic scan.

The second phase/ blood pool phase
• Obtained 5 minutes after injection. This shows the
relative vascularity to the area.
• Areas with moderate to severe inflammation have
dilated capillaries, which is where the blood flow is
stagnant and the radioisotope can "pool".
• This phase shows areas of intense or acute
inflammation more definitively compared with the
third phase.

The third phase, delayed phase
• Obtained 3 hours after the injection, when the
majority of the radioisotope has been metabolized.
• This phase best shows the amount of bone turnover
associated with a lesion.

⦿Gallium concentrates
avidly at the site of
infection following
local accumulation of
leucocytes and
proteins that are
labelled in vivo.
⦿ The radiation dose is
higher and the image
quality poorer.

4) COMPUTED TOMOGRAPHY:
⚫ Early detection of bonychanges
⚫Bettervisualization of axial skeletal involvement
⚫Betterdelineation of periosteal reaction and
sequestra.
⚫ Sequestra are shown as areas of dense or high
attenuation spicules of bone in areas of osteolysis.
⚫Cloacae, periostitis and soft tissue masses are
shown. These may enhancewith ivcontrast.

5) MRI:
• Highlysensitive and specific.
• STIR is the best sequence forosteomyelitis.
• Lesions appear HYPOINTENSE on T1
weighted imagesand HYPERINTENSE on
T2 weighted images.
T1 -weighting T2 - weighting STIR
NORMAL
CORTEX
LOW SIGNAL LOW SIGNAL LOW SIGNAL
OEDEMATOUS
CORTEX
LOW SIGNAL BRIGHT VERY BRIGHT
NORMAL
MEDULLA
VERY BRIGHT LESS BRIGHT LOW SIGNAL
OEDEMATOUS
MEDULLA
LOW SIGNAL ENHANCING
WITH GADOLINIUM
BRIGHT VERY BRIGHT

Figure 8–8 This 13-year-old boy presented with fever, leukocytosis, and
severe left hip pain. (A) A T1-weighted coronal MR image of the pelvis
demonstrates
decreased signal in the bone marrow of the left femoral neck.
(B) A T2-weighted image demonstrates a left hip joint effusion and increased
signal (edema) within the left femoral neck. This represented a
combination of septic arthritis and osteomyelitis.

COMPLICATIONS
 LOCAL COMPLICATIONS:
1) Chronic Osteomyelitis- most common
2) Acute pyogenic arthritis
3) Pathological fracture
4) Growth-plate disturbances- lengthening,
shortening and deformity of limb.
 SYSTEMIC COMPLICATIONS:
Septicemiaand metastatic abscess.

CHRONIC OSTEOMYELITIS
⚫FACTORS RESPONSIBLE FOR CHRONICITY-
1) General factors: nutritional status, vascular disease,
DM
2) Local factors: foreign body, sinus
3) Virulence of organism
4) Treatment: delayed, inadequate, inappropriate or
non-compliance to treatment
5) Risk factors- prosthesis, penetrating trauma

⚫C/F:- chronic discharging sinus is m/c presenting
symptom, minimal pain, low grade fever, tenderness
⚫Tibia is most commonly involved
⚫May be associated with SAPHO syndrome
⚫RADIOLOGICAL EXAMINATION-
1) Increased density ( sclerosis) of bone
2) Thickening and irregularity of bone
3) Periosteal new bone
4) Areas of destruction
5) Dense sequestra

⚫ COMPLICATIONS:-
1) Acute exacerbations
2) Pathological fracture
3) Growth disturbances
4) Joint stiffness
5) MARJOLIN’S ULCER: squamous cell
carcinoma within a cloaca usually 10-25
years later & painless.
6) Amyloidosis
7) SAPHO SYNDROME : Synovitis, acne,
pustulosis , hyperostosis and osteitis.

BRODIE’S ABSCESS
• Defined as a localized form of suppurative
osteomyelitis.
• C/F:- localized nocturnal limb pain, & relieved
byaspirin.
• Staph. aureus is the m/c bacterial agent.
• Metaphysisof tubular bones.
• Distal tibia is m/c site. Othersare proximal
tibia, distal femur, fibula & distal radius.

RADIOGRAPHIC
FEATURES: A well
circumscribed area of
bonedestruction with a
surrounding zone of
reactive sclerosis
(Doughnut Rim)
• Usually > 1 cm
• A metaphyseal
serpinginous tractwith
sclerotic border marks
the tractof infection.

BRODIE ‘S ABSCESS OSTEOID OSTEOMA
Radiolucency >1cm. Radiolucent nidus <1 cm and may have
a target centre of calcification.
Enhances on only delayed isotope scan. Enhances centrally both on blood pool
and delayed scan due to central
vascularity.
MRI: The necrotic tissue does not
enhance.
Penumbra sign is seen
MRI : The central vascular material will
have a brighter signal and
enhancement.
ARTERIOGRAM: Vascular Blush in the
radiolucent nidus confirms diagnosis.

GARRE’S SCLEROSING
OSTEOMYELITIS
• Chronic, low-grade, diffuse, non-purulent
osteomyelitischaracterized by the striking
absence of visible pathogens on tissue
culture.
• Only in children and young adults

• Found in the long
tubular bones with
fusiform thickening of
the bone.
• Lesion is cortical with
significant periostitis
& reactive new bone
formation.
• No bonedestruction
or sequestrum is
noted.

SUPPURATIVE SPONDYLITIS
⚫Affected only in 2-4% of thecases of
osteomyelitis.
⚫M/c involves the lumbar
vertebrae>thoracic
⚫In ivdrug abusers, Cervical spine is
involved
⚫C/F- backache(m/c), decreased motion,
local tenderness.

⚫Routeof infection:

⚫The age of the patient determines the location
and rate of spread and thus the radiological
features.
⚫<20 years: vascular channels to the disc exist
and disc infection occurs before vertebral
disease.
⚫Decrease in disc height, paraspinal edema.
⚫Eventually vertebral end plate destruction
occurs creating patchy areas of osteolysis
throughout the vertebral body.

⚫ADULTS: initial focus occurs at anterior
vertebral endplate-radiolucent & irregular
lesion.
⚫As the adult disc is avascular, the organisms
lodge adjacent to the subchondral plates and
involve the disc secondarily.
⚫Vertebral destruction & collapse occurs, with
soft-tissue paraspinal swelling.
⚫Intradiscal gas may be seen on CT in clostridia,
brucellosis, tuberculosis & streptococcal
infection.

• Soft tissue swelling-
 In cervical spine infections: Widening of the
retropharyngeal & retrotracheal spaces.
 In thoracic spine- Displacement of paraspinal
lines
 In lumbar spine- Paravertebral or psoas abscess
• Epidural abscess may occur.
• Osseous ankylosis may occur as a late sequelae

⚫BRUCELLA SPONDYLITIS:
Lumbar vertebra m/c
1. Diminished disc height
2. Loss of vertebral endplate
3. Anterior disco-vertebral erosions
4. Anterior osteophytes
5. Intradiscal gas

• SI JOINT INFECTION
Less common
Ivdrug abusers
Loss of articularcortex
Erosions of subchondral bone
Reactive sclerosis

CHILDHOOD INFLAMATORY DISCITIS
⦿Is a distinct entity from osteomylelitis of the
spine.
⦿Occurs from 1-16 yrs of age.
⦿Clinical presentation is similar to acute
osteomyelitis but less severe.
⦿Xray: latent period of 3-4 weeks.
⦿Disc space narrowing , fragmentation and
destruction of adjacent subchondral
endplate.

⚫Reactive end plate sclerosis occursas
disease progresses.
⚫Posteriorelements are spared.
⚫A mild spinal flexion deformity mayoccur
⚫MRI is the most sensitive technique.
Cortical destruction is seen on T1. Disc &
marrow inflammation is seen on T1,T2 and
STIR sequences.

SEPTIC ARTHRITIS
• More common in children, Male predominance
⚫Monoarticular involvement- knee (50%), hip
and ankle are most common sites of
involvement
⚫Staph aureus is the commonest causative
organism
⚫Others are:- gonococcus, H.influenza, E.
coli, pneumococcus, salmonella, brucella.

ROUTES OF INFECTION

CLINICAL FEATURES:
• High grade feverand malaise
• Erythema, swelling and pain overaffected
joint
• Altered gait- if weight bearing jointsare
involved
• Restricted rangeof movements
• LAB INVESTIGATIONS- raised ESR,
leucocytosis, positive blood or joint fluid
cultures

RADIOLOGIC FEATURES:
⚫PLAIN RADIOGRAPH:-
Soft tissuealterations-
1) Displacementof juxta-articular fat-early sign
2)Waldenstrom’s sign- in arthritis of hip joint
3)Rapid narrowing of joint space followed by
complete loss within few weeks
Osseousalterations-
1) Earliestsign is loss of normal subchondral cortical
bone
2)Moth eaten destructive pattern in metaphysis
3)Laminated periosteal response
4)Completeankylosisof joint in laterstages.

NORMAL FAT FOLDS IN HIP JOINT : GLUTEUS MEDIUS,ILIOPSOASAND
OBTURATOR INTERNUS.

⦿WALDENSTROM’S SIGN:
Measurement from inferiorand medial surface of
acetabulum (Kohlers teardrop) to the medial
margin femoral head is taken.
A measurement of >11 mm ora differenceof >2 mm
compared with opposite hip is a positive sign.

COMPLICATIONS:-
1) Deformity and stiffness
2) Pathological dislocation
3) Secondary osteoarthritis

TOM SMITH’S ARTHRITIS
• Septic arthritis of hip seen in infants.
• Osteomyelitis can rupture the metaphyseal cortex
enter the articulation and spread via the synovial
fluid to the epiphysis and subarticular bone.
• D/D- DDH.

• Bones that have metaphysis within the adjacent
joint capsule are predisposed to rapid
development of septic arthiritis
• Head of femur is completely destroyed by the
pyogenic process.
• C/F- unstable gait, affected leg is shorter & hip
movements are increased in all directions.

TUBERCULOSIS

TUBERCULOSIS OF BONES
⚫ Radiographic changes are seen at presentation.
⚫ Accounts for 3% of all cases of extrapulmonary TB
⚫ Targets the hips, knees, spine
⚫ Spinal tuberculosis is most common, accounts for 50% all
skeletal TB cases
⚫ Metaphysis is commonly involved,when long bones are
involved.
⚫ There is no surrounding zone of sclerosis.
⚫ Sequestra are small and absorbed by granulation tissue.
⚫ Periosteal reaction is not a prominent feature.

TUBERCULAR ARTHRITIS
• COMMON SITES: Hip
and knee joints.
Early features:
• Joint widening
secondary to effusion.
• Soft tissue swelling.
• Marginal erosions.
• Destruction of cortical
white line.
Tuberculous arthritis of the knee joint. Frontal radiograph demonstrates periarticular osteopenia (black arrow), peripheral
osseous erosions (white arrow), and relative preservation of the joint space. A triad of radiologic abnormalities (Phemister
triad) consisting of periarticular osteoporosis, peripherally located osseous erosion, and gradual diminution of the joint
space suggests the diagnosis of tuberculosis

 LATE FEATURES: Symmetrical narrowing of joint
space.
 Moth eaten osteolytic bone destruction.
 Juxta articular osteoporosis
 End stage is fibrous ankylosis of the joint.

PHEMISTER’S
TRIAD
PROGRESSIVE
JOINT SPACE
NARROWING
JUXTA ARTICULAR
OSTEOPOROSIS
PERIPHERAL
EROSIVE DEFECTS
OF THE ARTICULAR
SURFACES.

1) Slow , insidious onset.
2) Severe Juxta articular
osteoporosis
3) Slow and asymmetrical
Joint Space narrowing
4) Bony sclerosis
uncommon.
5) End Stage—fibrous
ankylosis.
Pyogenic
1) Acute presentation
2) Juxta articular
osteoporosis less severe
3) Early joint Space
narrowing
4) Bony sclerosis common
5) Bony ankylosis.
70
Tuberculous

UNUSUAL PRESENTATIONS OF
TUBERCULOSIS
• CARRIES SICCA: Tubercular destruction of the
humeral head with multiple erosive defects.
• CYSTIC TUBERCULOSIS: Multiple, symmetric,
well defined lytic lesions of the appendicular
skeleton.
• POTTS PUFFY TUMOR: A tubercular calvarial
lesion forming a button sequestrum and
fluctuant cold abscess on the scalp.
• WEAVER’S BOTTOM: Tubercular involvement
of the subgluteal bursae allowing direct
extension to the ischial tuberosity.

 TUBERCULOUS
DACTYLITIS:
Tubercular
destruction of the
tubular bones of the
hand and feet with
soft tissue swelling,
bone expansion and
thinning of cortex.
Also known as spina
ventosa.

TUBERCULAR SPONDYLITIS
⦿Spine is the most frequent site of skeletal TB.
⦿Radiological latent period 21 days.
⦿Most common site: lower thoracic and upper lumbar vertebrae.
 GENERAL: Insidious onset with constitutional symptoms like low
grade fever, anorexia, weight loss and night sweats.
 LOCAL:Back pain, tenderness, paraplegia or paraparesis, and kyphotic
or scoliotic deformities

Risk factors of spinal infections
 Advanced age > 50
 Intravenous drug abuse
 Immunosuppression or immune deficiency
 Long-term steroid administration
 Diabetes mellitus
 Organ transplantation
 Malnutrition
 Malignancy
 HIV infection
 Previous TB infection

Types of spinal involvement
1. Paradiscal
2. Central
3.Anterior
Atypical :
– Neural arch involvement only
– Spinal canal granulomas without bony
involvement
 Involvement of posterior elements is
rare

⚫ In the more common
paradiscal type
⚫ Infection begins in the
metaphyseal areas
⚫ Bone softensgets
compressed
⚫ anterior wedging or
total collapse
⚫ Spreads under the
anterior longitudinal
ligament to involve
adjacent Vertebra
Total collapse

 Approx. 75% of infected individuals develop a soft tissue
infection
⚫ PARA VERTEBRAL ABSCESS
CERVICAL : Retropharyngeal
THORACIC : Paravertebral & along ribs
LUMBAR : Psoas abscess
⚫ Commonly occurs in the psoas muscle “ cold abscess
”Known as cold abscess because forms slowly and does not
normally present with heat, inflammation or pain.
⚫ Paraspinal fistula which may form a communication with the chest
wall or pelvic floor
⚫ Left untreated, degeneration and inflammation of the vertebrae
causes
Herniation into the cord space cord compression and cauda
equina(NEUROLOGICAL COMPLICATION ,more in thoracic (narrowest canal)
⚫ Kyphosis gibbous (severe kyphosis)
⚫ Paraplegia

FEATURES OF POTT’S SPINE ON RADIOGRAPH
EARLY FEATURES:
⦿ lytic destruction at the anterior subchondral endplate
⦿ Loss of disc height
⦿ Paraspinal swelling
LATE FEATURES:
⦿ Vertebral body collapse.
⦿ Obliteration of the disc.
⦿ Gibbus formation.
⦿ Biomechanical stress on the
uninvolved vertebral body caudal
to the gibbus leads to increase in
height : width ratio known as LONG
VERTEBRA.

Atypical features
– Involvement of only one vertebral body
–Involvement of several vertebral bodies without intervertebral
discitis
– Bowing of rib cage secondary to collapse of multiple vertebral
bodies
– Destruction of lateral or posterior aspects of vertebral bodies

TB SPINE
RADIOLOGICAL FEATURES

Paraspinal abscess

COMPUTED TOMOGRAPHY
⚫ Demonstrates bone
destruction/erosions when x-
ray may be normal
⚫ Helps in better anatomic
localisation
⚫ Soft tissue findings
‐ Abscess with calcification
is diagnostic of spinal
TB; CT is excellent
modality to visualize soft
tissue calcifications
⚫ Evaluates areas such as C-V
junction, cervico-dorsal, sacrum
providing guidance for biopsy

• On contrast CT
• strong rim
enhancement
around low
attenuation
collection –
“Rind sign”

CT morphology
Four patterns of
bony destruction
is noted:-
1) Fragmentary (most
characteristic and
most common)
2) Osteolytic.
3) Subperiosteal.
4) Well-defined lytic
with sclerotic margins

 CT also demonstrates:
⚫Disc space narrowing
⚫Multilevel involvement
⚫Kyphosis

MRI
 Is the imaging modality of
choice
 Demonstrates early bone
marrow involvement/edema ,
spinal canal and neural
involvement
 Soft tissue and intraosseous
abscess are well
demonstrated, but poorly
visualizes calcification in
abscesses

 T1WI : shows a decreased signal
within the affected vertebral
marrow along with loss of disc
height
 Cortical definition of Vertebra is
lost
 Disc space narrowing is also
seen but limited to degree of
bone destruction
 T2WI : shows an increase in
signal intensity within the
involved Vertebra and disc

 Enhanced MR
studies:
show inhomogenous
enhancement in the
region of marrow
infiltration

Sagittal T2W (Images 1-3)and axial T1W (Image 4)
High intensity activity in T12 to L3 vertebrae indicative of infection (*) (*).
Complete destruction of
vertebral bodies with osseous retropulsion into the spinal canal, causing
cauda equina (*). On axial
view, note destruction of vertebral body with loss of circular shape(*).
MRI …

EPIDURAL ABSCESS
T1WI Post Gd T2WI

⚫ Paraspinal soft tissue
masses ( seen in 71% of
cases)
⚫ T1WI :
⚫ Loss of uniform signal
intensity
⚫ Enlargement of affected
muscle alteration of
paraspinal soft tissue
⚫ T2WI :
⚫ hyperintense
⚫ Post–contrast :
⚫ Thick rim enhancement
around intraosseous
and paraspinal soft
tissue abscess
⚫ Also delineate
communication
between vertebral and
paravertebral
components

CORD CHANGES
 Plain x-ray or CT: little
information
 Cord involved by
compression or direct
extension of disease
 MRI :
– shows cord edema
or myelomalacia in
cord as
hyperintense signal
on T2WI
 Indicate irreversible
neurological damage

MRI :
⚫Post treatment follow
up can be done ideally
⚫progressive increase in
signal intensity on
T1WI correlates well
with resolving
symptoms
⚫Reduction in
gadolinium
enhancement is useful
sign of healing
⚫However, increase in
soft tissue mass , bone
destruction do not
indicate failed
treatment

NUCLEAR MEDICINE
SCINTIGRAPHY
⚫Is economical ,highly sensitive but non-
specific
⚫Uptake is increased in osseous
tuberculosis
⚫Reveals multiple sites in disseminated
disease
⚫Have reported many false-negative
bone scans
⚫Seen in disseminated TB, cervical spine
regions and neural arch lesions
⚫Limits the use of scintigraphy

Differential diagnosis
1. Pyogenic infection :
– Often difficult
– Sudden onset with swinging temperature
– Rapid bone destruction and rapid disc
involvement
– Replaced by pronounced new bone
formation and sclerosis
– However,calcification indicates TB

2. Degenerative Spondylosis :
Clinical findings allow differentiation
Disc space is usually not markedly
narrowed
T2WI : disc dessication is seen as low
signal intensity
3.Brucella Spondylitis :
H/O undulent fever
Lower lumbar vertebra are
characterstically involved
Erosion of anterior upper or lower margins
Step like deformity or rounding-off the
corner
Extensive sclerosis

4.Metastatic Deposits :
– Collapse of diseased vertebrae but
disc remains unaffected
– Involvement of other bones and
destruction of pedicles suggest
metastasis
• Other D/D :
– Multiple myeloma , chordoma
– Primary bone tumors
– Lymphomas , sarcoidosis
– Bizzare infections :fungal, syphilitic ,

Features:- Tubercular Pyogenic
Onset of
symptoms
Insidious Acute
Site of
predilection
Dorsolumbar Lower lumbar
Multifocal
involvement
common Not common
Vertebral body
destruction
Extensive focal
Posterior
element
May be involved Spared
99
Tubercular spondylitis Vs Pyogenic spondylitis

Features:- Tubercular Pyogenic
Disc destruction late early
Paraspinal mass large small
Calcification in
paraspinal mass
yes NO
Enhancement of
paraspinal mass
peripheral patchy
Spinal deformity common Uncommon
Bone sclerosis Absent present
100

MYCOTIC INFECTIONS

MADUROMYCOSIS
• Chronic granulomatous
fungal disease affecting
the feet.
• Caused by Nocardia
madurae, Nocardia
brasiliensis.
• Localized swelling ,
purulentdischarge
from sinus tracts.
• Osseous lesionsoccur
as a direct extension
from the soft tissues.

• Tarso-metatarsal region is
most commonly affected.
• Widespread lytic
destructive lesions with
filiform or undulating
deformity.
• Fistula formation is
common.
• Periosteal reaction is
minimal.
• Sequestrum is
characteristically absent.

⚫In advanced cases, nearlyall bones of the footare
involved.
⚫Diffuse intraarticular ankylosis occurs as sequela.
⚫MRI FINDINGS: Generalized low signal intensity
of the matrix with lesions of high signal intensity
interspersed throughout.
⚫Within these high signal intensity lesions, a low
intensity focus can be identified known as DOT
IN CIRCLE SIGN.
⚫This sign is highly specific for mycetomaof the
foot.

ACTINOMYCOSIS
⚫It is an unusual suppurativebacterial infection. Infective
agents- Actinomyces israelii and bovis
⚫2 types- cervicofacial type (m/c) and chest & abdominal
varieties
⚫The mandible is the most commonly involved.
⚫Thecharacteristic feature is a lytic destructive lesion at
the angle of the mandible with little or no periosteal
reaction.
⚫Abscess formation and draining sinuses are associated
with mandibular lesions.
⚫Other bones involved are ribs, spineand pelvis.

Osteolytic lesion with periosteal reaction of posterior body and ramus of
mandible with the soft tissue infiltrative changes in skin , messator muscle
and parotid gland

COCCIDIOIDOMYCOSIS
⚫Caused by Coccidioides immitis
⚫Skeletal involvement is secondary to respiratory
infection
⚫Mimics tuberculosis
⚫Bone involvementoccurs in 20% of cases.
⚫Spine, pelvis, ribs and bony prominences such as tibial
tuberosity, malleoli, trochanters, acromion, patella &
olecranon are involved.
⚫Nocharacteristic radiological criteria.
⚫Bone lesions resemble theappearances of acute and
chronicosteomyelitis.

• SPINAL COCCIDIOIDOMYCOSIS:
Thoracicand lumbarvertebra
Lucent lesions in vertebral body, pedicles &
lamina
Sparing of discspaces
CONTIGUOUS RIB INVOLVEMENT is
characteristic
Paraspinal mass (abscess formation)

OTHER INFECTIONS

CONGENITAL SYPHILIS
⦿ PHASE1:METAPHYSITIS:P
resent at birth or shortly
thereafter.
⦿ Spirochaetes are lodged
beneath the fetal growth
plates producing a
metaphysitis.Bone
formation in the zone of
ossification is decreased
creating radiolucent
metaphyseal bands

⦿ These bands lead to
metaphyseal irregularity
with fragmentation and
infarctions referred as
sawtoothed appearance.
⦿ WIMBERGERS SIGN:B/L
erosive defects on the
medial margin of the
proximal tibia.

• Phase1 lesions heal without therapywithin
2weeks.
• PHASE2:PERIOSTITIS:The periosteum is
infiltrated with syphilic granulation tissue
creating a diffuse,symemetrical,solid or
laminated reaction affecting all long bones.

• PHASE3:OSTEITIS:Infantswho have not
received therapycan developosteitis.
• Syphylitic granulation tissue can extend
from the metaphysis to the diaphysis
creating osteolytic lesions surrounded with
reactive sclerosis.

⦿ Anterior bowing of the
tibia with Extensive
periosteitisand cotical
overgrowth givean
undulating dense
contourto the long
bones (SABER SHIN).
⦿ osteolyticdefects can
also be seen
(GUMMATA).

ADDITIONAL FEATURES
• CLUTTON’S JOINTS:
B/L painless synovitis of jointsespecially the
knee joints.
• HUTCHISON’S TEETH :
Deformityof the teeth creating peg shaped ,
hypoplasticand notched teeth.

ACQUIRED SYPHILIS
• Fewer than 10% of the patients develop osseous lesions.
• Skeletal manifestations are seen in tertiary syphilis
• Superficial part of the skeleton which are the skull, tibia
and clavicles are usually involved.
• There is diffuse proliferative periostitis leading to
diffuse thickening of the inner and outer cortices.This
periosteal reaction is known as lace like pattern.
• Pseudobowing of tibia mayoccur.
• Syphilitic osteomyelitis may be localised(gumma) or
diffuse(gummatous osteitis). There is sclerosis with
irregularity of bone trabeculation.

LEPROSY
⦿ OSTEITIS LEPROSA: Granulomas cause focal cortical and
medullary destruction.Small cysts are seen known as
OSTEITIS MULTIPLEX CYSTICA LEPROSA.
⦿ Bone loss may occur both longitudinally and
circumferentially.
• This gives rise toa ‘ LICKED CANDY STICK’
appearance.
• Diffuse non specific osteoporosis.
• Featuresof superimposed pyogenic osteomyelitis.
• Nervecalcification.

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