septic arthriti
● is an inflammatory joint disease
s
caused by bacterial, viral, and
fungal infection.
Route of infection
● dissemination of pathogens via the blood, from
distant site…. (most common
● dissemination from an acute osteomylitic focu
● dissemination from adjacent soft tissue infection,
● entry via penetrating trauma
s
)
● entry via iatrogenic means
Etiology
● The causal organism is usually Staphylococcus aureus
● In children under the age of 3 years Haemophilus
.
n
influenzae is fairly commo
● gram-negative bacilli (a group of bacteria, including
Escherichia coli, or E. coli)
● streptococci (a group of bacteria that can lead to a
wide variety of diseases)
Pathology
● There is an acute synovitis with a purulent joint effusion and
Synovial membrane becomes edematous, swollen and
hyperemic, and produces increase amount of cloudy
exudates contains leukocytes and bacteri
● As infection spread through the joint, articular cartilage is
destroyed by bacterial and cellular enzymes
● If the infection is not arrested the cartilage may be
completely destroyed
● Pus may burst out of the joint to form abscesses and sinuses
.
.
a
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● The joint may be become pathologically dislocated.
Acute suppurative arthritis – pathology In the early stage (a), there is an acute synovitis
with a purulent joint
effusion. (b) Soon the articular cartilage is attacked by bacterial and cellular enzymes. If
the infection is not arrested, the
cartilage may be completely destroyed (c). Healing then leads to bony ankylosis (d).
With healing there will be:(end result
)
● Complete resolution and return to normal.
● Partial loss of cartilage and fibrosis.
● Bone ankylosis
● Bone destruction and permanent deformity.
Clinical presentation
● Typical features are acute pain and swelling in a single
large joint ,commonly the hip in children and the knee in
adults, however any joint can be affected.
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●
)
The emphasis is on septicemia rather than joint pain
Irritability ,Fever, refuses to feed, rapid pulse
Unable to move the limb with the infected joint
(pseudoparalysis) .
Cries when infected joint is moved (diaper changing
Infection is usually suspected ,but it could be anywhere so
the joints should be carefully felt and moved to elicit the
local signs of warmth ,tenderness and resistance to
movement.
Umbilical cord or the site of injection should be
examined for possible source of infection.
If the baby is distressed and wont move his/her leg think
of hip infection.
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Symptoms in newborns or infants
1.
2. In children
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:
Acute pain in single large joint
The joint is swollen (if superficial), warm
and tender
Fever
All movements are restricted due to
muscle spasm (Pseudoparesis).
➢
3.
In adult:
➢
➢
➢
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Intense joint pain .
Joint swelling .
Joint redness .
Unable to move the limb with the infected
joint .
Low-grade fever.
Physical examination
1.
Decreased or absent rang of motion
2.
Signs of inflammation: joint swelling, warmth,
tenderness and erythema
3.
Joint orientation as to minimize pain (position
of comfort)
Hip: abducted, flexed and externally rotated
➢ Knee, ankle and elbow: partially flexed
➢ Shoulder: abducted and internally rotated
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:
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Investigation
Lab studies
● The diagnosis can usually be confirmed by
● joint aspiration and immediate microbiological
investigation of the fluid.
● Blood culture may be positive in about 50% of proven cases.
● Non specific features of acute inflammation-
:
leucocytosis,ESR,CRP-are suggestive but not diagnostic .
Ask for
gram stain, culture, leukocyte count with
differential, and crystal examinatio
● leukocyte count
o generally higher than 50,000/µL, with a predominance
of neutrophils more than 75
gram stain
n
%
:
:
:
are positive in approximately 75% of patients with
staphylococcal infections; however, results are positive in
only 50% of patients with gram-negative infections
● crystal examination
● exclude crystal-induced arthritis (may coexist
● culture
● The definitive metho
● for aerobic and anaerobic organisms
● are positive in 85-95
• Synovial fluid glucose, protein, and lactic acid
)
.
:
%
d
:
concentration not specific.
Imaging studie
1-Plain x-ray
● The appearance of significant x-ray findings depends upon
the duration and virulence of infection.
● Plain radiography findings are generally nonspecific and
may reveal only soft tissue swelling ,widening of the joint
space ( due to the effusion), and periarticular osteoporosis
during the first 2 weeks
● Later ,when the articular cartilage is attacked ,the joint
.
s
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space is narrowed.(persistent subluxation, destructive
arthritis).
Septic arthritis
of the ankle
2-Ultrasonography
This study is very sensitive in detecting joint effusions
generated by septic arthritis.
➢ Ultrasound can be used to define the extent of septic arthritis
and help guide treatment.
➢ Ultrasound helps to differentiate septic arthritis from other
conditions (e.g., soft tissue abscesses, tenosynovitis) in which
treatment may differ.
➢
● 3-Radio-isotope bone scan
➢Show increase uptake of the isotope in the region of the
:
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:
joint. (may help in difficult site as sacroiliac &
sternoclavicular joint
4- CT scan
➢ This study may help to diagnose sternoclavicular or
sacroiliac joint infections.
5-MRI:
➢MRI is most useful in assessing the presence of
periarticular osteomyelitis as a causative mechanism.
DIFFERENTIAL DIAGNOSIS
● Osteomyelitis: near a joint may be indistinguishable from septic
arthritis ;the safest is to assume that both are present.
● An acute haemarthrosis :either post-traumatic or due to a
haemophilic bleed ,can closely resemble infection. The history is helpful
and joint aspiration will resolve any doubt.
● Transient synovitis(irritable joint) in children: causes symptoms
and signs which are less acute ,but there is always the that this is the
beginning of an infection.
● Gout and pseudogout in adults :aspirated fluid may look turbid but
the presence of urate or pyrophosphate crystals will confirm the diagnosis.
● Rheumatic fever
complication
● Dislocation: a tense effusion may cause dislocation
● Epiphyseal destruction: in neglected infants the largely
cartilaginous epiphysis may be destroyed ,leaving an unstable
pseudarthrosis.
● Growth disturbance: physeal damage may result in shortening or
deformity
● Ankylosis: if articular cartilage is eroded healing may lead to
ankylosis
● Secondary osteoarthriti
s
● Osteomyleitis/abcess/sinus
● arthritis stiffness,
● dislocation, subluxation
● AVN
● local growth distrubance,
● osteomyelitis,
,
,
● postinfection synovitis
Treatment
● General Measures
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:
The first priority is to aspirate the joint and examine the
fluid, treatment is then started without further delay
➢Analgesics and splinting of the involved joint in the
position of maximal comfort alleviate pain.
➢Fluid replacement and nutritional support may be
required.
➢Other foci of infection and any coexisting medical
conditions must be identified and treated
appropriately.
● Intravenous antibiotics should be given empirically and
started as soon as joint fluid and blood sample have been
taken for culture.
● If gram –positive organisms are identified ,Flucloxacillin
is suitable . If in doubt ,a third generation cephalosporin
will cover both game+ and gram- organisms
● Children less than 4 yr( if suspicion of H.Infl) treated with
Ampicillin
● Once the bacterial sensitivity is known the appropriate
drug is substituted
● Intravenous administration is continued for several
.
.
.
weeks and is followed by oral antibiotics for a further 2
or 3 weeks.
Drainage
Indication of Surgical Drainage
1-Joints that do not respond to antimicrobial therapy and
daily arthrocentesi
2-. Any joint with limited accessibility, including the
sternoclavicular or the hip join
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t
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3-Patients with underlying disease, including diabetes,
rheumatoid arthritis, immunosuppression, or other
systemic symptoms, should be treated more aggressively
with earlier surgical intervention
● Splinting for 48 hr
s
● Weight bearing once worm and pain subsided
Prognosis and complications
● Poor prognosis factor
● Immunodeficiency, RA, prematurity, osteomyelitis, hip,
prosthetic infections, + blood cultures, symptoms >1
week, >4 joints, + cultures after aspiration after 7 days of
abx t
● Complications
● Mortality 8%-15%
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● Favorable outcome in 50%-80% of cases
Thank you