Septic arthritis is an inflammation of the synovial membrane caused by infection, most commonly due to Staphylococcus aureus. It can present differently in infants, children, and adults, typically characterized by joint pain, swelling, and restricted movement. Early diagnosis and treatment are critical, involving joint aspiration, antibiotics, and possibly surgical drainage to prevent permanent joint damage.

1. Septic
arthritis
Dr . Ebtisam
Alariqi.
Consultant of
orthopedic.
Done by:
Dhoha
Almasani

2. Definition
Septic arthritis is an inflammation of synovial membrane
with purulent effusion into the joint capsule due to
infection.
" Also referred as infectious arthritis "

3. Causative organism
 staphylococcus aureus; is the commonest.
 in children between 1 and 4 years old,
Haemophilus influenzae is an important
pathogen unless they have been vaccinated
against this organism.
 Occasionally other microbes, such as
Streptococcus, Escherichia coli and
Proteus, are encountered

6. Route of infection:
 HEMATOGENOUS SPREAD
Most common form of spread, usually affects people
with underlying medical
problems.
• DIRECT INNOCULATION
May result from penetrating trauma,
introduction of organisms during
diagnostic and surgical procedures.
E.g. intra-articular injection.
• DIRECT SPREAD FROM ADJACENT BONE
More common in children. Osteomyelitis usually
begins in the metaphyseal region, from which it breaks
through the periosteum into the joint.

8. " The prevalence of bacterial arthritis as the
diagnosis among adults presenting with one or
more acutely painful joints has been estimated to
range from 8%" 27%
" All age groups, infants and older adults are most
likely to develop septic arthritis.
٠ 50% < age 3
- M = F
" commonly the hip in children and the knee in
adult, however any joint can be affected.
Incidence

9. Predisposing factors
1. AGE
• Age >80 years old
2. EXISTING JOINT PROBLEMS
• Chronic diseases and conditions that affect the joints — such as osteoarthritis,
gout, rheumatoid arthritis or lupus - can increase the risk of septic arthritis, as
can an artificial joint, previous joint surgery and joint injury.
3. MEDICATIONS
• Taking medications for rheumatoid arthritis. People with rheumatoid arthritis
have a further increase in risk because of medications they take that can
suppress the immune system, making infections more likely to occur.
4. SKIN FRAGILITY
• Skin that breaks easily and heals poorly can give bacteria access to your body.
Skin conditions such as psoriasis and eczema increase your risk of septic
arthritis, as do infected skin wounds. People who regularly inject drugs also
have a higher risk of infection at the site of injection.
5. WEAK IMMUNE SYSTEM
• People with a weak immune system are at greater risk of septic arthritis. This
includes people with diabetes, kidney and liver problems, and those taking
drugs that suppress their immune systems.
6. ALCOLOISM AND IVDU.

10. pathology

11. pathology
*Bacteria rapidly gains access to the joint cavity and settles in
the synovial membrane.
*Infection start in the synovium synovitis synovial
membrane becomes edematous, swollen and hyperemic
effusion first serous, then sero-purulent, then frank pus.
*Articular cartilage is eroded and destroyed due to the action
of bacterial toxins and by enzymes released from the
synovium and inflammatory cells.
*In late cases extensive erosion due to synovial
proliferation and ingrowth.
*If untreated spread to the underlying bone or burst out of
the joint to form abscesses and sinuses.

12.  With healing:
• Complete resolution and return to normal (if treated properly
before cartilage damage).
• Partial loss of cartilage and fibrosis of joint.
• loss of articular cartilage and bony ankylosis.
• Bone destruction and permanent deformity of the joint.

13. Clinical picture

14. Clinical picture
• differ somewhat according to the age of the patient:
 In newborn infants: the emphasis is on septicemia rather
than joint pain.
1. irritability, fever, refuses to feed, rapid pulse.
2. Loss of spontaneous movement of the limb with the infected
joint.(pseudoparalysis).
3. Cries when infected joint is moved (diaper changing)
4. Hip flexion, abduction and externally rotated.
• The joints should be carefully felt and moved to elicit the local
signs of warmth, tenderness and resistance to movement.
• The umbilical cord should be examined for a source of
infection.
• An inflamed intravenous infusion site should always excite
suspicion. The baby’s chest, spine and abdomen should be
carefully examined to exclude other sites of infection.

16. Clinical picture
 In children:
1. acute pain in a single large joint .
2. Restriction of movement (pseudoparesis).
3. The child is ill, with a rapid pulse and a swinging fever.
4. The overlying skin looks red and in a superficial joint
swelling may be obvious, there is local warmth and
marked tenderness.
5. All movements are restricted, and often completely
abolished, by pain and spasm.
• It is essential to look for a source of infection – a septic
toe, tonsillitis or a discharge from the ear.

17. Clinical picture
In adult:
it is often a superficial joint (knee, wrist, a finger, ankle or toe).
1. Intense joint pain.
2. Joint swelling, redness, warmth and marked local
tenderness.
3. Restriction of movements.
4. Low grade fever.
the patient should be questioned and examined for evidence of
gonococcal infection, drug abuse or rheumatoid arthritis.

18. Physical examination
1. Limitation of both active and passive movement of the
joint in all direction (early due to muscle spasm and late due
to ankylosis)
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.

19. Investigation:
Blood investigation:
1. The WBC count, CRP and ESR are raised.
2. Blood culture (may be positive).
Synovial fluid analysis:
The diagnosis can usually be confirmed by joint aspiration
and immediate microbiological investigation of the fluid.
* It may be frankly purulent but inn early cases the fluid my
look clear.
* The sample sent for: Gram staining, microscopy, culture, and
antibiotic sensitivity.
* the normal synovial fluid leucocyte count is under 300 per
mL; counts of over 50 000 per mL with predominance of PNL
are highly suggestive of sepsis.
* Gram-positive cocci are probably Staphylococcus aureus;
Gram-negative cocci are either Haemophilus influenzae or
Kingella kingae (in children) or Gonococcus (in adults).
* Crystal examination : to exclude gout or pseudogout.

21. Imaging:
1. X-ray :
• Early stage: May look normal except widening of joint space(due to
effusion), and soft tissue swelling.
• Late stage: Narrowing and irregularity of joint space; may have OM
changes of adjacent bone.

24. 2- ultrasound:
is the most reliable method for revealing a joint effusion in
early cases. Both hips should be examined for comparison.
Widening of the space between capsule and bone of more than
2 mm is indicative of an effusion, which may be echo-free
(perhaps a transient synovitis) or positively echogenic (more
likely septic arthritis).
3- MRI and radionuclide imaging:
are helpful in diagnosing arthritis in obscure sites such as
the sacroiliac and sterno-clavicular joint.

26. Differential diagnosis
1- Acute osteomyelitis: pain and tenderness over metaphysis, not on joint line
In young children, osteomyelitis may be indistinguishable from septic arthritis; often
one must assume that both are present.
2- Other types of infection: Systemic features will obviously be the same as those of
septic arthritis.
3- An acute haemarthrosis: either traumatic or due to hemophilic bleeding, can
closely resemble infection.
A history is helpful and joint aspiration will be .
4- Irritable joint (transient synovitis): causes symptoms and signs which are less
acute , but always this is the beginning of an infection.
US may help to distinguish septic arthritis from transient synovitis.
5- Rheumatic fever: polyarticular, fleeting and there are no signs of septicemia.
6- Juvenile rheumatoid arthritis: This may start with pain and swelling of a single
joint, but the onset is usually more gradual and systemic symptoms less severe than in
septic arthritis.
7- Sickle-cell disease: The clinical picture may closely resemble that of septic
arthritis – and indeed the bone nearby may actually be infected! – so this condition
should always be excluded in communities where the disease is common.
8- Gaucher’s disease: In this rare condition acute joint pain and fever can occur
without any organism being found (‘pseudo-osteitis’). Because of the predisposition to
true infection, antibiotics should be given.
9- Gout and pseudogout: In adults, acute crystal-induced synovitis may closely
resemble infection. On aspiration the joint fluid is often turbid, but the presence of urate
or pyrophosphate crystals will confirm the diagnosis.

27. complications
1. Spread of infection:
 General: septicemia, toxemia and pyemia.
 Local: osteomyelitis, pus may burst out of the joint to form abscesses
and sinus.
2. Pathological Subluxation and dislocation of the hip, or
instability of the knee should be prevented by appropriate
posturing or splintage.
3. Damage to the cartilaginous epiphysis in the growing child is
the most serious complication.
4. Growth disturbance: physeal damage may result in shortening
or deformity.
5. Articular cartilage erosion (chondrolysis) may lead to either
fibrosis or bony ankylosis
5. In adult partial destruction of the joint will result in secondary
osteoarthritis.

28. Treatment
 Considered as medical emergency.
 Failure to initiate appropriate antibiotic
therapy within the first 24 to 48 hours of
onset can cause subchondral bone loss
and permanent joint dysfunction.
 It can cause septic shock, which can be
fatal.

29. • The first priority is to aspirate the joint and examine the
fluid, treatment is then started without further delay.
Drainage:
*if the aspirate looks purulent, the joint should be drained without
waiting for laboratory results.
*Under anesthesia the joint is opened through a small incision, drained
and washed out with normal saline. A small catheter is left in place and
the wound is closed; suction–irrigation is continued for another 2 or
3 days (This is the safest policy) and is certainly advisable to:
(1) in very young infants.
(2) when the hip is involved.
(3) if the aspirated pus is very thick.
(4) Loculation noted in MRI or US.
(5) Don’t respond to serial aspiration.
*For the knee, arthroscopic debridement and copious irrigation may
be equally effective.
*Older children with early septic arthritis (symptoms for less than
3 days) involving any joint except the hip can often be treated
successfully by repeated closed aspiration of the joint; however, if
there is no improvement within 48 hours, open drainage will be
necessary.

30. ANTIBIOTICS:
• Broad spectrum IV antibiotics are started immediately and then
depending on microbiological investigations, specific antimicrobial
therapy is started.
• Duration of treatment:
 IV antibiotics given for minimum of 2 weeks.
 Oral antibiotics: Children-2-4 weeks.
Adults- 4-6 weeks.

31. SPLINTAGE:
• The joint should be rested, and for neonates and infants this
may mean light splintage; with hip infection, the joint
should be held abducted and 30 degrees flexed, on traction
to prevent dislocation.
General supportive care :
1. IV fluids to prevent dehydration.
2. Analgesics for pain.
3. Other foci of infection and any coexisting medical
conditions must be identified and treated
appropriately.

32. AFTERCARE:
• Once the patient’s general condition is improving, and
the joint is no longer painful or warm, further damage
is unlikely.
• If articular cartilage has been preserved, gentle and
gradually increasing active movements are encouraged.
• Check CRP& WBC every 2 days.
• Continue treatment for 2-3 weeks with oral or iv
antibiotics after discharge.