Chronic non-specific infection of bone and joint

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• Chronic non-specific infection of bone and joint

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Chronic osteomyelitis
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• Chronic osteomyelitis
• is a severe, persistent, and sometimes
  incapacitating infection of bone and bone marrow.
  It is often a recurring condition because it is
  difficult to treat definitively.

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• This disease may result from
• (1) inadequately treated acute OSM (2) a
  hematogenous type of osteomyelitis (3) trauma,
  (4) iatrogenic causes such as joint replacements
  and the internal fixation of fractures (5)
  compound fractures (6) infection with organisms,
  such as Mycobacterium tuberculosis and Treponema
  species (syphilis) and (7) contiguous spread
  from soft tissues, as in diabetic ulcers or
  ulcers in peripheral vascular disease

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• Pathophysiology
• Infective process
• Osteomyelitis is an infective process involving
  all osseous components, including bone marrow.
  Chronic osteomyelitis results when the
  inflammatory process continues over time, leading
  to bone sclerosis and deformity.
• The ends of long bones are the most common locus
  of infection, and Staphylococcus aureus is the
  most common infective organism involved.
  Traumatic fractures or previous surgery may be
  responsible creating the access for infection,
  which may also originate from sepsis in the
  hematogenous form.

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Pathophysiology
Infection at the bone locus creates an increase
of intramedullary pressure due to inflam matory
exudate that strips the periosteum, leading to
vascular thrombosis followed by bone necrosis and
the formation of sequestra. Usually, necrosis of
the large segments of bone leads to sequestrum
formation. These sequestra with infected material
are surrounded by sclerotic bone that is
relatively avascular. The haversian canals are
blocked with scar tissue, and the bone is
surrounded by thickened periosteum and scarred
muscle. Antibiotics cannot penetrate these
relatively avascular tissues and are hence
ineffective in clearing the infection. New bone
formation occurs at the same time (involucrum).
Multiple openings appear in this involucrum,
through which exudates and debris from the
sequestrum pass via the sinuses. A periosteal
reaction acts to circumscribe the sequestrum,
producing a thick sheet of new bone or involucrum.
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• Organisms Commonly Isolated in Osteomyelitis
  Infants (lt1 year) Group B streptococci
  Staphylococcus aureus Escherichia coli
  Children (1 to 16 years) S. aureus
  Streptococcus pyogenes Haemophilus influenzae
  Adults (gt16 years) Staphylococcus epidermidis
  S. aureus Pseudomonas aeruginosa Serratia
  marcescens E. coli

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• Organism Comments
• Staphylococcus aureus   Organism most often
  isolated in all types of osteomyelitis
  Coagulase-negative staphylococci or
  Propionibacterium species   Foreign-bodyassociate
  d infection Enterobacteriaceae species or
  Pseudomonas aeruginosa   Common in nosocomial
  infections Streptococci or anaerobic bacteria  
  Associated with bites, fist injuries caused by
  contact with another person's mouth, diabetic
  foot lesions, decubitus ulcers Salmonella species
  or Streptococcus pneumoniae
•   Sickle cell disease Bartonella henselae   Human
  immunodeficiency virus infection Pasteurella
  multocida or Eikenella corrodens   Human or
  animal bites Aspergillus species, Mycobacterium
  avium-intracellulare or Candida albicans  
  Immunocompromised patients Mycobacterium
  tuberculosis   Populations in which tuberculosis
  is prevalent Brucella species, Coxiella burnetii
  (cause of chronic Q fever) or other fungi found
  in specific geographic c

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• Anatomy
• Cierny and Mader proposed an anatomic
  classification of chronic osteomyelitis
• Type 1 - Endosteal or medullary lesion
• Type 2 - Superficial osteomyelitis limited to the
  surface
• Type 3 - Localized, well-marked legion with
  sequestration and cavity formation
• Type 4 - Diffuse osteomyelitis lesions

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• Physiologic Factors affecting immune
  surveillance metabolism and local vascularity -
  Systemic factors (Bs) malnutrition, renal or
  hepatic failure, diabetes mellitus, chronic
  hypoxia, immune disease, extremes of age,
  immunosuppression or immune deficiency - Local
  factors (Bl) chronic lymphedema, venous stasis,
  major vessel compromise, arteritis, extensive
  scarring, radiation fibrosis, small-vessel
  disease, neuropathy, tobacco abuse

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• Frequency
• United States
• The prevalence of chronic osteomyelitis is 5-25
  after an episode of acute osteomyelitis. The
  prevalence of tuberculous osteomyelitis is 1-5
  of the population affected by tuberculosis. The
  incidence in developed countries is low.
• International
• The incidence in developing countries is higher
  than in other countries, although the exact
  incidence is not known.
• Mortality/Morbidity
• Mortality from osteomyelitis was 5-25 in the
  preantibiotic era. Presently, the mortality rate
  is approaching 0.
• Complications of osteomyelitis include (1) septic
  arthritis, (2) destruction of the adjacent soft
  tissues, (3) malignant transformation (eg,
  Marjolin ulcer squamous cell carcinoma,
  epidermoid carcinoma of the sinus tract), (4)
  secondary amyloidoses, and (5) pathologic
  fractures

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Clinical presentation

• chronic forms of osteomyelitis usually occur in
  adults. Generally, these bone infections are
  secondary to an open wound, most often an open
  injury to bone and surrounding soft tissue.
  Localized bone pain, erythema and drainage around
  the affected area are frequently present. The
  cardinal signs of subacute and chronic
  osteomyelitis include draining sinus tracts,
  deformity, instability and local signs of
  impaired vascularity, range of motion and
  neurologic status. The incidence of deep
  musculoskeletal infection from open fractures has
  been reported to be as high as 23 percent.6
  Patient factors, such as altered neutrophil
  defense, humoral immunity and cell-mediated
  immunity, can increase the risk of osteomyelitis

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• Presentation
• Unlike acute osteomyelitis, chronic osteomyelitis
  causes no acute constitutional symptoms. The
  presenting features may be those of a
  long-standing, discharging sinus or chronic bone
  pain and persist despite treatment. Patients may
  also present with acute exacerbations and usually
  have a previous history of acute osteomyelitis,
  sometimes dating back to childhood. Other
  symptoms include deep boring pain, especially in
  cases of a Brodie abscess. In osteomyelitis that
  occurs after joint replacement, the main symptom
  is the recurrence of pain.
• Findings in tuberculosis include the following
• History of tuberculosis elsewhere
• Attacks of fever and lassitude
• Night cries
• Intense episodes of pain in the affected bones
• Muscle wasting, synovial thickening, and
  restriction of joint movement in all directions
• Kyphosis, back pain, and symptoms and signs of
  spinal cord compression in spinal tuberculosis
• Findings in syphilis include the following
• Pain, refusal to move the affected limb
• Restriction of movement in an adjacent joint
• Pain in the bone
• Local swelling, redness, and warmth

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• Fever
• Nausea
• General discomfort, uneasiness, or ill feeling
  (malaise)
• Drainage of pus through the skin (in chronic
  osteomyelitis)
• Additional symptoms that may be associated with
  this osteomyelitis include the following
• Excessive sweating
• Chills
• Low back pain
• Swelling of the ankles, feet, and legs
• Physical examination shows bone tenderness and,
  possibly, swelling and redness.
• During laboratory testing, a full blood count may
  show leukocytosis. The erythrocyte sedimentation
  rate (ESR) is elevated. Blood cultures may help
  identify the causative organism.
• Results of bone lesion biopsy and cultures may be
  positive for the organism. A skin lesion with a
  sinus tract (ie, the lesion tunnels under the
  tissues) may yield pus for culturing.

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• Diagnosis
• The diagnosis of osteomyelitis is based primarily
  on the clinical findings, with data from the
  initial history, physical examination and
  laboratory tests serving primarily as benchmarks
  against which treatment response is measured.
  Leukocytosis and elevations in the erythrocyte
  sedimentation rate and C-reactive protein level
  may be noted. Blood cultures are positive in up
  to one half of children with acute osteomyelitis.
  
• The palpation of bone in the depths of infected
  pedal ulcers in patients with diabetes mellitus
  is strongly correlated with the presence of
  underlying osteomyelitis (sensitivity, 66
  percent specificity, 85 percent positive
  predictive value, 89 percent negative predictive
  value, 56 percent).7 If bone is palpated, the
  evaluation may proceed directly to microbiologic
  and histologic confirmation of osteomyelitis, and
  thereafter to treatment. Further diagnostic
  studies are unnecessary.
• chronic stage of hematogenous osteomyelitis is
  known as a Brodie's abscess.

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• Histopathologic and microbiologic examination of
  bone is the gold standard for diagnosing
  osteomyelitis

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• microbiologic examination
• Cultures of sinus tract samples are not reliable
  for identifying causative organisms. Therefore,
  biopsy is advocated to determine the etiology of
  osteomyelitis.14 However, the accuracy of biopsy
  is often limited by lack of uniform specimen
  collection and previous antibiotic use

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• Laboratory Investigations
• CBC with differential
• Elevated WBC count
• Left shift Polymorphonucleocytosis
• Blood cultures
• ESR (Normal lt 20 mm/hr)
• Usually elevated gt 35mm
• C-Reactive Protein (Normal lt 8 - 10mg/L)
• Elevated gt 10mg/L

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Diagnostic Imaging

• Plain Radiographs
• Ultrasound
• Radionuclide (Bone) Scans
• C-T Scans
• M R I

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• Radiography
• Findings
• Plain radiographic
• findings in acute or subacute osteomyelitis are
  deep soft-tissue swelling, a periosteal reaction,
  cortical irregularity, and demineralization. The
  chronic phase of the disease is characterized by
  thick, irregular, sclerotic bone interspersed
  with radiolucencies, an elevated periosteum, and
  chronic draining sinuses.
• Sclerosing osteomyelitis of Garré most commonly
  affects the mandible and appears with a focal
  sclerosing periosteal reaction on radiologic
  studies.
• Chronic recurrent osteomyelitis is benign
  self-limiting condition that primarily affects
  long bones in children and adolescents. The
  metaphysis of long bones are usually affected,
  and changes may be symmetrical. The appearances
  are those of confluent areas of bone lysis.
• .
• False Positives/Negatives
• Stress fractures, osteoid osteomas, and other
  causes of periosteitis may mimic acute or chronic
  osteomyelitis.

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Osteomyelitis, chronic. Sequestrum of the lower
tibia
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Osteomyelitis, chronic. Sclerosing osteomyelitis
of the lower tibia. Note the bone expansion and
marked sclerosis.
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Sequelae of Osteomyelitis Chronic Sinus
Intermittent drainage Sequestrum Dead
bone (sclerotic) Failure to resorb
Involucrum New bone envelope Pathologic
fracture
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• Computed Tomography
• CT is of definite value for studying the entire
  articular surface of bone and periarticular soft
  tissues for delineating the extent of medullary
  and soft-tissue involvement and for
  demonstrating cavities, serpiginous tracts,
  sequestra, or cloacae in osteomyelitis.
• CT scans sometimes show soft-tissue edema or bone
  destruction not seen on plain images,
  particularly in the setting of acute
  osteomyelitis. Sclerosis, demineralization, and
  periosteal reactions are usually well depicted in
  chronic osteomyelitis.
• CT scanning also helps in evaluating the need for
  surgery, and it provides vital information about
  the extent of disease. This data helps in
  planning appropriate surgery. CT is also an
  important modality in image-guided biopsy.
• False Positives/Negatives
• Stress fractures, osteoid osteomas, and other
  causes of periosteitis may mimic acute or chronic
  osteomyelitis

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Osteomyelitis, chronic. Axial CT scans show
destruction of L1. Note the air in the soft
tissues
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Osteomyelitis, chronic. CT scans show vertebral
osteomyelitis associated with a psoas abscess
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Osteomyelitis, chronic. Nonenhanced axial CT
scans through the first and second toes in the
same patient as in Images 5-7 shows cortical
irregularity of the distal phalanx of the hallux
this finding is suggestive of chronic
osteomyelitis. The final diagnosis was
osteomyelitis of the first and second toes,
plantar fasciitis, and psoriatic arthritis of the
fifth metatarsal-phalangeal joint.
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• Magnetic Resonance Imaging
• Findings
• MRI findings in osteomyelitis are usually
  secondary to the replacement of marrow fat with
  water secondary to edema, exudate, hyperemia, and
  bone ischemia. Findings include the following
  decreased signal intensity in the involved bone
  on T1-weighted images, increased signal intensity
  in the involved bone on T2-weighted image, and
  increased signal intensity in the involved bone
  on short-tau inversion recovery (STIR) images.
• Sequestrum of cortical bone appears hypointense
  on T1-weighted, T2-weighted, and STIR MRIs and
  shows no gadolinium enhancement. Sequestrum of
  cancellous bone is hyperintense relative to
  cortical sequestrum on T1-weighted, T2-weighted,
  and STIR MRIs and shows no gadolinium
  enhancement. The involucrum is hypointense on all
  3 images and shows gadolinium enhancement.
• Granulation tissue is hypointense on T1-weighted
  images and hyperintense on T2-weighted and STIR
  images. It shows gadolinium enhancement.
  Similarly, draining sinuses and soft-tissue
  inflammation are hypointense on T1-weighted
  images and hyperintense on T2-weighted and STIR
  MRIs however, it does show gadolinium
  enhancement.
• .

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Osteomyelitis, chronic. T1- and T2-weighted
sagittal MRIs show bone marrow edema in L1 and
obliteration of the disk space between L1 and L2
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Contrast Gadolinium Enhancement
Gadolinium enhanced
T2 Weighted Image
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MRI Gold Standard Soft tissue bony changes
Changes appear early Accurately
localizes subperiosteal or soft
tissue collections Sensitivity of 100 for
bone marrow edema No ionizing radiation
Disadvantages Cost Need for sedation in
most infants and children
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• Degree of Confidence
• MRI has sensitivity and specificity higher than
  those of plain radiography and CT, and it is
  particularly good at depicting bone marrow
  abnormalities. On MRI, marrow signal abnormality
  is more sensitive than lytic changes on plain
  images, and findings become positive earlier with
  MRI than with radiography. Intramedullary bone
  pathology can be directly visualized with MRI,
  and in osteomyelitis marrow, these findings may
  precede bone changes.
• reaction and associated soft-tissue involvement

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• The multiplanar capability of MRI is an advantage
  and provides better anatomic detail and better
  soft-tissue contrast. MRI is especially good in
  assessing vertebral osteomyelitis, which has a
  characteristic pattern of confluent vertebral
  body and disk involvement. Titanium and other
  orthopedic devises usually pose no problem apart
  from artifacts.
• However, MRI findings of osteomyelitis are
  nonspecific, and similar changes can occur as a
  result of tumors, fractures, and a variety of
  other intramedullary or juxtamedullary processes
  that may cause bone marrow edema. The sensitivity
  and specificity has been reported as 92-100 and
  89-100, respectively. Prior fracture changes due
  to surgery or the fracture itself are difficult
  to differentiate from infection.
• False Positives/Negatives
• Fractures, bone bruises, and benign or malignant
  bone tumors may all mimic osteomyelitis.

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• Ultrasonography
• Findings
• Cleveland and Peck reported a case in which
  high-resolution ultrasonography was instrumental
  in establishing a diagnosis of chronic
  osteomyelitis. Sonograms depicted a periosteal

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Nuclear Imaging Gallium-67 scanning. Technetium-99
m diphosphonate bone scanning A99m Tc methylene
diphosphonate (MDP) bone scans are usually
positive 24 hours after an acute infection, and
the scans demonstrate a well-defined focus of
tracer activity 1-2 hours after the injection.
This finding is correlated with radiotracer in
same area on dynamic scans. Bone scintigraphy may
show focal uptake at the affected site and is
particularly valuable in looking for other sites
of infection, as multifocal osteomyelitis may
occur. MDP scans also remain positive in most
patients with subacute and chronic osteomyelitis.
Increased focal activity may persist in sterile
disease for up to 2 years following successful
therapy. The sensitivity of MDP scans can be
improved by using a 3-phase bone scan. On such
scans, focal activity is usually depicted
associated with mild, diffusely increased,
regional activity distal to the sight of
osteomyelitis. Occasionally, a photon deficient
(cold) defects are seen.
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Osteomyelitis, chronic. Radiograph (left) and
isotopic bone scans (right) show sclerosing
osteomyelitis of the tibia
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Radionuclide Imaging Bone Scan Technetium
diphosphonate New bone formation (osteoid)
Reflects osteoblastic activity Higher
sensitivity with longer duration of illness
Bone Scan can be -ve Very early osteomyelitis
Absent blood supply Neonates have
less mineralization (30 sensitivity) Useful
for occult multifocal lesions
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Osteomyelitis, chronic. Three-phase
technetium-99m diphosphonate bone scans
(perfusion component) show increased activity in
the whole of the heel, the tarsus, the proximal
and distal phalanges of the hallux, and the
proximal phalanx of the second toe
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Osteomyelitis, chronic. Indium-111labeled WBC
scans show an infected right-knee prosthesis
40
Bone scans, both anterior (A) and lateral (B),
showing the accumulation of radioactive tracer at
the right ankle (arrow). This focal accumulation
is characteristic of osteomyelitis
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• Treatment
• Chronic osteomyelitis in adults is more
  refractory to therapy
• and is generally treated with antibiotics and
  surgical debridement. Empiric antibiotic therapy
  is not usually recommended. Depending on the type
  of chronic osteomyelitis, patients may be treated
  with parenteral antibiotics for two to six weeks.
  However, without adequate debridement, chronic
  osteomyelitis does not respond to most antibiotic
  regimens, no matter what the duration of therapy
  is. Outpatient intravenous therapy using
  long-term intravenous access catheters (i.e.,
  Hickman catheters) decreases the length of
  hospital stays.28-30 .

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Treatment

• Oral therapy
• using fluoroquinolone antibiotics for
  gram-negative organisms is presently being used
  in adults with osteomyelitis.23 None of the
  currently available fluoroquinolones provides
  optimal antistaphylococcal coverage, an important
  disadvantage in view of the rising incidence of
  nosocomially acquired staphylococcal
  resistance.31 Furthermore, the current quinolones
  provide essentially no coverage of anaerobic
  pathogens

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• Debridement Acute hematogenous osteomyelitis is
  best managed with a four- to six-week course of
  appropriate antimicrobial therapy. Chronic
  osteomyelitis is generally treated with
  antibiotics and surgical debridement. Surgical
  debridement in patients with chronic
  osteomyelitis can be technically demanding. The
  quality of the debridement is the most critical
  factor in successful management. After
  debridement with excision of bone, it is
  necessary to obliterate the dead space created by
  the removal of tissue. Dead-space management
  includes local myoplasty, free-tissue transfers
  and the use of antibiotic-impregnated beads. Soft
  tissue procedures have been developed to improve
  local blood flow and antibiotic delivery

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• Specific forms of chronic osteomyelitis
• Other forms of chronic osteomyelitis include
• A Brodie abscess is a form of chronic
  osteomyelitis without a preceding episode of
  acute osteomyelitis..
• Tuberculous osteomyelitis of the bone is
  secondary spread from a primary source in the
  lung or GI tract. It most commonly occurs in the
  vertebrae (body) and long bones. Once
  established, the bacilli provoke a chronic
  inflammatory reaction. Small patches of caseous
  necrosis occur, and these coalesce to form larger
  abscesses. The infection spreads across the
  epiphysis into the joints. The infection may
  track along soft tissue to appear as a cold
  abscess

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congenital syphilis. The transplacental spread of
spirochetes from mother to the fetus results in
Long bones, such as the tibia, are mainly
affected. Congenital syphilis has 2 forms
periosteitis and metaphysitis. In periosteitis,
the periosteum is lifted of the diaphysis of long
bone with subperiosteal new-bone formation. This
process gives the characteristic appearance
called sabre tibia. In metaphysitis, the
juxtaepiphyseal metaphysis is involved with
increased bone resorption. Absent osteoblastic
activity results in separation of the epiphyseal
from the metaphysis. acquired syphilis, bone
lesions are manifestations of tertiary syphilis.
Gummatous lesions appear as discrete punched-out
radiolucent lesions in medulla or destructive
lesions within the cortex. The surrounding bone
is sclerotic, and no discharge is present.
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• A Brodie abscess
• is a subacute osteomyelitis with a predilection
  for the ends of long bones and the carpus and
  tarsus. Plain radiographic findings include the
  following (1) a central area of radiolucency
  with a surrounding thick rim of reactive bone
  sclerosis, which may persist for months (2)
  pathognomonic tortuous parallel lucent channels
  extending toward the growth plate (3) a variable
  degree of periosteal new-bone formation and (4)
  associated soft-tissue swelling.

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• A Brodie abscess is characterized by a double
  line at the site of the lesion due to the high
  signal intensity of granulation tissue surrounded
  by low signal intensity of bone sclerosis on
  T2-weighted MRIs. The lesion has
  low-to-intermediate signal intensity that is
  outlined by a hypointense rim on T1-weighted MRIs.

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Brodies abscess, a localised radiolucency
usually seen in the metaphyses of long bones. It
is sometimes difficult
Treatment of Brodies abscess in the
metaphysis includes surgical
curettage
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Tuberculosis of Skeletal System
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T9
T10
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Abscess
Cold abscess
Prevertebral Muscle sheath
Paravertebral abscess
Lumbar abscess
Gluteal abscess
Retropharyngeal abscess
Retropleural abscess
Retroperitoneal abscess
Iliac abscess
Femoral abscess
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Cold abscess Destruction of soft
tissues. Destruction of bone. Hyperemia.
Kyphosis
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Neurological Deficit
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Pott's Spine
Chemotherapy
Surgery
Surgery
Medical
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Decompression Stabilization
Medical
Anterior Fixation
Antero posterior Fixation
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pus
Abscess
Anterior Instrumentation
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