Transcript osteomyelitis

ETIOLOGY
 acute hematogenous osteomyelitis
 subacute osteomyelitis
 chronic osteomyelitis
osteomyelitis
 Osteomyelitis may occur at any age.
 Most common in ages 3-12 years.
 It affected boys twice frequently as girls .
 A microbial ethiology is confirmed in three
fourth of osteomyelitis and two thirds of
cases of septic joint
pathogenesis
1. Hematogenous
2. Direct spread from a contiguous focus of
infection.
 Osteomylitis in children is most often the
consequence of bacterremia.
Pathogenesis
(con)
 involves growing bone . Particularly the
metaphyses of the long bone .
 Femur and tibia are equally and together almost
half of the all cases .
(distal femur , proximal tibia ,distal humerus ,
distal radius)
Pathogenesis
(con)
 Bacteria lodge in nutrient arteries supplying the
growth plates of bones.
 Blood in the large sinusoidal veins flows slowly
 No phagocytic cells present in this area.
 Obstruction of flow by bacterial microemboli
produces small areas of avascular necrosis and
metaphyseal abscess .
1. Bacteria lodge in nutrient arteries supplying the
growth plates of bones.
2. Blood in the large sinusoidal veins flows slowly.
No phagocytic cells present in this area.
3. bstruction of flow by bacterial microemboli produces
small areas of avascular necrosis and
metaphyseal abscess .
pathogenesis
(con)
 Trauma often is noted before the onset of
osteomyelitis. (in about one third)
 In infant<1 yr the capillaries perforate the
epiphyseal growth plate .
 Spread across the epiphysis ,which causes a
septic arthritis .
pathogenesis
(con)
 Pyartheritis complicating osteomyelitis is
common in joints :
that capsule inserts to the metaphysis proximal to
the epiphyseal plate .
 ( hip, elbow, shoulder , knee)
capsule inserts to the
metaphysis proximal to the
epiphyseal plate .
( hip, elbow, shoulder , knee)
Chronic osteomyelitis
 Involucrum:
Infected periosteum calcify into a shell of new bone
around the infected portion of the shaft .
 Brodie abscess: a subacute intraosseous
abscess that does not drain into the subperiosteal
space and is classically located in the distal tibia
 Sequestrum:
portions of avascular bone that have
separated from adjacent bone, frequenrly are covered
with a thickened sheat
Contiguous osteomyelitis
 Less common in children
 Usually occur after the spread of cellulitis as a
result of Infected wound .
■ osteomyelitis also may result from direct
inoculation of a penetrating wound
■ Primary viral infection of bones or joints are rare
etiology
 S.aureus is responsible for most infections in
all age groups.
 Group B ( neonate) or other streptococci(A)
and pneumococcus , anaerobic microorganism
, gram-negative entric bacteria, M,tuberculosis
.
 furunculosis , infected burns ,varicella, trauma,
drug abuse ,prolong IV or central parenteral
alimentation
etiology
 Sickle cell anemia :
( salmonella , staphylococcus and less common
S.pneumonia)
 Cat or dog bite ( pasteurella multocida)
 Puncture wounds ,IV drug abuse (pseudomonas)
 H,influ type b account for more than half of all case
but is rarely seen in an immunized population .
Clinical manifestations
 Hematogenous osteomylitis usually involves a
single bone.
 The most common presenting complaints are
focal pain, exquisite point tenderness over the
bone, warmth, erythema, swelling, and
decreased use of the affected extremity.
 Fever, anorexia, irritability, and lethargy may
accompany the focal findings.
Clinical manifestations
 Weight bearing and spontaneous or requested
motion are refused .( pseudoparalysis)
 Hematogenous vertebral osteomyelitis is
insidious onset. With little fever or systemic
toxicity.
 Pelvic osteomyelitis present with limp
,abdominal, hip ,groin ,pain and fever
Clinical manifestations
 Neonate 40% multiple site
local edema
reduced limb motion
GBS,E coli
S,aureus
joint effusion (60-70)
 1-24 mo
long bones
involve joints

metaphysis of focal pain+ fever (90%)
long bones
focal tenderness (70%)
rarely vertebral joint effusion (20%)
pelvis
2-20 yr
pseudoparalysis
fever,limp
S,aureus
GBS
S,aureus(60-90%)
strep(10%)
diagnosis
 Marked tenderness over the involved site.
 leukocytosis may be present , ESR ↑, CRP ↑
 Blood culture ( 60% positive).
 Cultures of aspirated cellulitis or priosteal space
before antibiotic therapy.
diagnosis
 Radiography :
• finding of acute systemic osteomyelitis, at about 9
days, is loss of the periosteal fat line
• Periosteal elevation and periosteal destruction are
later findings
 technetium 99m bone scans .
 MRI is particularly useful for extended of infection
or when infection is a complication of trauma ,
surgery, sickle cell anemia
treatment
 Initial IV antibiotic should be based on result of
Gram stain of bone aspiration ,blood culture, age
associated disease.
 Initial IV antibiotic should cover S.aureus
(oxacillin,nafcillin methicillin, clindamycin)
 Possibility of methicilin –resistant staph should be
considered .
 Gram- negative organism if wound contamination
or IV drug abuse .
treatment ( con)
 sickle cell anemia S.aureus and salmonell must be
covered (cefotaxim ,ceftriaxon)
 The response to appropriate IV antibiotic usually
occur in 48 hr .
 Lack of improvement in fever and pain after this
time indicates that surgical drainage may be
necessary or an unusual pathogen may be present .
Treatment ( con)
 surgical drainage may be appropriate at earlier
time if :
1.
sequestrum is present
2.
disease is chronic or atypical
3.
the hip joint is involved
4.
Presence of spinal cord compression.
standard therapy usually consist of antibiotic for 4-6 weeks
 After initial inpatient treatment and a
good clinical response, including
decreases in CRP or ESR,
consideration may be given for home
therapy with IV antibiotics or oral
antibiotics,
Septic Arthritis
 It occurs most commonly during the first 2 yr
of life and adolescence.
 Half of all cases occur by 2 yr and three fourths
occur by 5 yr .
 Joints of the lower extremity constitute three
fourth of all cases.
pathogenesis
1. Hematogenous dissemination of bacteria.
2. Contaguous spread from surrrounding tissues.
3. Spread of osteomyelitis through the epiphysis
into the joint space in young children .
Presenting in the first 3 days more often
represent the hamatogenous spread of bacteria
.
pathogenesis
 Post infectious joint effusion :
Which is sterile .
caused by antigen- antibody complex.
Developed after 7 days of bacterial illness.
( bacteremia, meningitis, diarrhea , urethritis)
etiology
 S.aureus is the most common agent.
 H.influ type b is the most common factor in 3
month to -4 yr .
 Streptococci , pneumococci, meningococci that
may occure in the absence of sepsis or
meningitis.
 Gonococcal arthritis most common cause of
polyartheritis and monoarticular artheritis in
adolecent.
Clinical manifestation
 Erythema , warmth , swelling, and tenderness with
a palpable effusion and decreased range of
movement . Toddlers demonstrate a limp .
 Acute septic arthritis most often involves a single
joint .
 Multiple joints in 10% .
1. The onset may be sudden with fever and chills
2. Insidious with symptoms noted only when the joint
is moved .
Clinical manifestation( con)
 Often difficult to assess septic arthritis of the
hip and may cause referred pain the knee .
 The hip for minimize pain from pressure ,The
limb may be positioned in external rotation and
flexion .
 The knee and elbow joints usually are in
flexion .
diagnosis
 Leukocytosis , elevated ESR or CRP are
common .
 Arthrocentesis is the test of choice for rapid
diagnosis .
 Blood or joint cultures are positive in 70%up to
85% in cases
 ultraSonography is helpful in detecting joint
effusion and may guide localization for
aspiration .
 Plain radiographs typically add little
information to the physical findings.
 Radiographs may show swelling
of the joint capsule, a widened joint
space, and displacement of adjacent
normal fat lines.
 Radionuclide scans are of limited
use, although technetium-99m
 bone scans may be helpful to exclude
concurrent bone infection, eithir
adjacint or distant from the infected
joint.
 MRI is useful in distinguishing joint
infections from cellulitis or deep
abscesses.
diagnosis
(Synovial fluid analysis)
 Synovial fluid analysisfor cell count, diff ,protein
and glucose has limited usefulness .
 Noninfection inflammatory disease can also
increased cells and protein and decreased
glucose
(rheumatic fever , and rheumatoid arthritis)
diagnosis
 In up to 30% of patients who have never
received antibiotic may not reveal bacterial
pathogens .
 In chronic arthritis synovial biopsy may
distinguish between an septic and a non
infection process.
 Radiography or bone scans of adjacent bone .
Differential diagnosis
 Reactive arthritis is immune-mediated synovial
inflammation thar follows a bacrerial or viral
infection
 Non infectious
(Rheumatoid arthritis , SLE,serum sickness , IBD)
 Henoch –schonlein purpura, leukemia
,metabolic diseases , foreign bodies , traumatic
arthritis
 viral infections may cause arthritis
 Suppurative arthritis must be distinguished
from Lyme disease, osteomyelitis,
suppurative bursitis, fasciitis, myositis,
cellulitis, and soft tissue abscesses.
 Psoas muscle abscess often presents with
fever and pain on hip flexion and rotation
Differential diagnosis
Toxic tenosynovitis of the hip
 Common condition of children age 3-6 years .
 May be viral in etiology .
 Selflimited disorder and more common than septic
arthritis .
bacterial infections (TB, syphilis.Lyme disease)
treatment
 Therapy is based on :
1. Likely organism
2. Gramstain of joint fluid
3. host immunologic status
Parenteral antimicrobial agents.
Surgical intervention reserved for specific
situation.
treatment
(CON)
 Pyogenic arthritis of the hip or shoulder caused
by S.aureus usually necessiatates prompt
surgical drainage.
 Staphylococcal infection of the knee may be
treated with repeated arthrocenteses and
countinuation of appropriate IV antibiotics
treatment
(CON)
For empirical therapy:
 in the neonate antibiotic against
staphyloccocci, GBS, and aerobic gramnegative.
( cefotaxim or ticarcillin / clavulanate)
 Infant 3 month- 4 years antibiotic against
S. aureus and H .influ type b until culture results
are known .
( cefotaxim or ampicillin /sulbactam)
treatment
(CON)
 IV meticillin is the choice for S.aureus .
 Vancomycin for methicillin- resistant .
 The length of therapy depends on :
1. Clinical resolation
2. reduction of ESR .
S.Aureus 14-21 days or more .
Gonococcal or meningococcal 7 days of penicillin
treatment
(CON)
 Oral agents against s.aureus are:
augmentin.cloxacillin , dicloxacillin , cephalexin
, clindamycin, and ciprofloxacin these are
often used to complete therapy .