Acute non-specific infection of the bone and the joints

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Acute non-specific infection of the bone and the
joints
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• Definition
• Septic arthritis is an infection in a joint.
  Bacteria, or less commonly fungi, can spread from
  other infected areas in the body to a joint.
  Sometimes bacteria infect only the joint.
• In septic arthritis, germs infiltrate joint
  usually just one and damage it, causing severe
  pain.
• Bacteria most commonly target knee, though other
  joints can be affected by septic arthritis,
  ankle, hip, wrist, elbow and shoulder.
• Young children and older adults are most likely
  to develop septic arthritis..

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• Symptoms
• Fever
• Shaking chills
• Severe pain in the affected joint, especially
  when you move that joint
• Swelling of the affected joint
• Warmth in the area of the affected joint
• The joints of your arms and legs, especially the
  knees, are most commonly affected by septic
  arthritis. In rare cases other joints, such as
  those the back, neck and head, may be affected.

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• Causes
• Septic arthritis may develop when an infection
  elsewhere in the body, such as an upper
  respiratory tract infection or urinary tract
  infection, spreads through bloodstream to a
  joint. Less commonly, a puncture wound, drug
  injection or surgery near a joint may allow
  bacteria into the joint.
• The lining of joints (synovium) has little to
  protect itself from infection. Once bacteria
  reach the synovium, they enter easily and can
  begin destroying cartilage. causing inflammation
  around the joint, increasing pressure in joint
  and reducing blood flow to the joint
  contributes to the damage of joint.

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• Types of bacteriaA number of strains of bacteria
  can cause septic arthritis. The most common type
  involved in septic arthritis is Staphylococcus
  aureus (staph) .
• In the past, septic arthritis was more frequently
  caused by the bacterium that causes the sexually
  transmitted disease gonorrhea. But use of safer
  sex practices has led to a decline in gonorrhea
  and its complications, including septic
  arthritis. Still, in younger sexually active
  people, gonorrhea is a potential cause of septic
  arthritis.
• Other infectious causes of arthritisBacteria are
  just one cause of joint infections. Viruses also
  can attack joints (viral arthritis), though this
  condition usually resolves on its own and causes
  little joint damage. In rare cases, joint
  infections can be caused by a fungus (fungal
  arthritis). Another infectious type of arthritis
  is reactive arthritis, which causes joint pain in
  response to an infection in another part of the
  body, though the joint itself isn't infected

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• Risk factorsExisting joint problems.
• Diseases and conditions that affect joints
  including other types of arthritis, gout,
  pseudogout and lupus may increase risk of
  septic arthritis. An artificial (prosthetic)
  joint, previous joint surgery and joint injury
  also increase risk.
• medications for rheumatoid arthritis
• . Rheumatoid arthritis medications may suppress
  the immune system, making infections more likely
  to occur. Also, diagnosing septic arthritis in
  people with rheumatoid arthritis is difficult
  because many of the signs and symptoms are
  similar.
• Skin fragility. Diseases and conditions that make
  skin wounds common give bacteria easy access to
  body. Skin conditions such as psoriasis and
  eczema increase risk, as do skin infections.
  People who regularly inject drugs also have a
  higher risk of infection at the site of
  injection.
• Weak immune system. People with diabetes, kidney
  and liver problems, and those taking drugs that
  suppress their immune systems (immunosuppressive
  drugs) have an increased risk of infections

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• Complications
• Prompt treatment with antibiotics usually
  resolves the infection. If treatment is delayed,
  however, the infection can quickly lead to joint
  degeneration usually within five to seven days
  and permanent damage. Complications of septic
  arthritis often include osteoarthritis and joint
  deformity. In severe cases, the joint may need to
  be surgically reconstructed. If the infection
  affects a prosthetic joint, the prosthetic joint
  may need to be replaced

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• Tests and diagnosis
• The following tests typically help diagnose
  septic arthritis
• Joint fluid analysis. takes a sample of the fluid
  within joint (synovial fluidjoint. Synovial fluid
  normally appears clear and thick. Bacterial
  infections can alter the color, consistency,
  volume and makeup of the synovial fluid. the
  synovial fluid and then sends the fluid to a lab
  for analysis, including tests to determine what
  organism is causing your infection.
• Blood tests. Your doctor may order blood tests to
  see if bacteria are present in your bloodstream.
• Imaging tests. X-rays and other imaging tests of
  the affected joint also may be ordered to assess
  any damage to the joint.

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• Treatments and drugs
• antibiotic drugs and joint drainage when treating
  septic arthritis.
• Antibiotic drugsto identify the bacterium that's
  causing infection and then selects the most
  effective antibiotic to target that specific
  bacterium. Antibiotics may be given
  (intravenously) at first. Later, in some cases,
  you may be able to switch to oral antibiotics.
  How long you undergo antibiotic treatment depends
  on the type of bacteria infected with and the
  extent of the infection. Typically, treatment
  lasts about two to six weeks.
• Antibiotics carry a risk of side effects,
  including nausea, vomiting and diarrhea. Allergic
  reactions also can occur.
• Joint drainageRemoving the infected synovial
  fluid from your joint serves three purposes It
  removes bacteria from joint, reduces pressure on
  joint, and sample to test for bacteria and other
  organisms. The most common method of removing
  joint fluid is through arthroscopic surgery.
• In other cases, doctors may remove fluid from
  your joint with a needle (arthrocentesis).
  Arthrocentesis may be repeated,, until no
  bacteria are found in the extracted fluid. Hips,
  which are more difficult to access, may require
  open surgery to remove the synovial fluid.
  Surgery may need to be repeated in certain cases.
  
• .

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• Bone and Joint Infections
• Acute Hematogenous Osteomyelitis
• Bone and bone marrow infection is caused (most
  commonly) by blood-borne organisms. Commonly
  affects children (boysgtgirls). Staph. aureus is
  the most common offender. Anaerobic infections
  are also frequently seen, with Peptococcus magnus
  (G) appearing more frequently than Bacteroides
  (G-). The infection is most common in the
  metaphyses or epiphyses of long bones (lower
  extremity gt upper extremity). Radiographic
  changes include soft tissue swelling early,
  demineralisation (10 days to 2 weeks), and
  sequestra (dead bone with surrounding granulation
  tissue) and involucrum (periosteal new bone)
  later Pain, loss of function, and sometimes a
  soft tissue abscess are present.).

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• Elevated WBC count and ESR and positive blood
  cultures are usually seen. Bone scan (delayed
  up-take in bone) gallium (in spine infections)
  or indium (in extremity infections) scans may be
  helpful in equivocal cases. MRI shows changes
  usually before plain films (nonspecific low
  signal intensity in marrow spaces on both T1 and
  T2 images

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• Aspiration
• is helpful for antibiotic choice. IV antibiotics
  followed by a course of oral antibiotics after
  the temperature has normalised (total of 6 weeks
  or until the ESR returns to normal),
  immobilisation, and for refractory cases surgical
  drainage (saving bone from further destruction)
  are usually curative. Recurrence is high for
  metatarsal lesions (50), around (25). Long term
  morbidity is gt25.

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• Subacute Osteomyelitis
• Usually discovered radiologically in a patient
  with a painful limp and no systemic (and often no
  local) signs or symptoms, often from partially
  treated acute osteomyelitis, occasionally
  developing in a fracture haematoma. Unlike acute
  osteomyelitis, WBC count and blood cultures are
  frequently normal. ESR, bone cultures, and
  radiographs are often useful. Most commonly
  affects the femur and tibia, and unlike acute
  osteomyelitis, it can cross the physis even in
  older children.

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• Radiographic changes include Brodies abscess, a
  localised radiolucency usually seen in the
  metaphyses of long bones. It is sometimes
  difficult to differentiate from Ewings sarcoma.
  When localised to the epiphysis only, other
  lesions (such as chondroblastoma) must be ruled
  out. Epiphyseal osteomyelitis is caused
  exclusively by Staph. aureus. Epiphyseal
  osteomyelitis requires surgical drainage only if
  pus is present (48 hours of IV antibiotics
  followed wise).

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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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Soft Tissue Infections

• - Cellulitis An inflammatory infection of the
  subcutaneous tissues, usually due to staph or
  strep (and Haemophilus in children). Local
  erythema, tenderness, and occasionally
  lymphangitis/lymphadenopathy make up the clinical
  picture. (Fig).Ordinarily, mild cases of
  cellulitis can be treated with an oral
  penicillinase-resistant penicillin or
  cephalosporin. Patients with high fever, systemic
  toxicity, poor host resistance, or underlying
  skin diseases should be admitted for IV
  antibiotic therapy.

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• Significant Streptococcal Infections
• Several serious diseases are related to specific
  streptococcal infections.
• Erysipelas - Group A strep causes this
  progressively enlarging, red, raised, and painful
  plaque seen preominately in infants, diabetics,
  elderly, and patients with predisposing skin
  ulcers. Severe toxicity, fever, leukocytosis, and
  bacteraemia are common. Treatment with high doses
  of IV penicillin is essential for this
  life-threatening disease.
• Necrotising Fasciitis - Aggressive,
  life-threatening fascial infection that is often
  associated with underlying vascular disease (esp.
  diabetes

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• Significant Streptococcal Infections
• Several serious diseases are related to specific
  streptococcal infections.
• Erysipelas - Group A strep causes this
  progressively enlarging, red, raised, and painful
  plaque seen preominately in infants, diabetics,
  elderly, and patients with predisposing skin
  ulcers. Severe toxicity, fever, leukocytosis, and
  bacteraemia are common. Treatment with high doses
  of IV penicillin is essential for this
  life-threatening disease.
• Necrotising Fasciitis - Aggressive,
  life-threatening fascial infection that is often
  associated with underlying vascular disease (esp.
  diabetes).
• causing gangrene of four limbs
  necessary amputations

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• Gas Gangrene
• Classically caused by Clostridia species (G
  rod), but also can develop from G - and sometimes
  G (strep) infections. Clinical presentation
  usually includes progressive pain edema (distant
  from wound) foul smelling, serosanguineous
  discharge and feeling of impending doom.
  Radiographs typically show widespread gas in
  tissues. Treatment with high-dose penicillin (and
  aminoglycoside and cephalosporin), hyperbaric
  oxygen (inhibits toxins), and surgical ID are
  required.

Tetanus - Dont ever forget. Potentially lethal
neuroparalytic disease caused by an exotoxin of
Clostridium tetani, a G anaerobic rod. Treatment
is centred on prophylaxis with proper wound care
and tetanus toxoid administration (and TIG for
patients with severe wounds and without known
previous immunisations).
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. Toxic Shock Syndrome - Severe staph infection
that usually develops postoperatively . Surgical
Wound Infection - There has been a recent
increase in the incidence of Staph, epidermidis
wound infections. Staph. aureus is still the most
common infection overall, and in trauma patients.
Methicillin-resistant staph species infections
are also increasing. Puncture Wounds of the
Foot - Commonly are infected with Pseudomonas
(from shoewear), and require aggressive
debridement and appropriate antibiotics. Common
in children.
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• Summery
• Extra-information

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• Septic Arthritis - Commonly follows hematogenous
  spread or extension of osteomyelitis follow
  diagnostic or therapeutic procedures. Bacteria
  have a special affinity to exposed collagen
  matrix. Most cases involve infants (esp. hip),
  and children (knee).. There is pain, swelling,
  redness and pseudo-paralysis RA ,(tuberculosis)
  and drug abuse (Pseudomonas) can predispose
  adults. Haemophilus influenzae is the most common
  organism in children lt5 yo (Rx chloramphenicol or
  a third-generation cephalosporin), staph in
  children gt5 yo (Rx methacillin or oxacillin), and
  gonococci in adults (penicillin).
  Third-generation cephalosporins (ceftraidime,
  cefsulodin, and aztreonam) are now favored over
  aminoglycosides (with the possible exception of
  gentamicin) for the treatment of G- infections.
  treatment.

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• Surgical drainage (often arthroscopically) or
  daily aspiration
• Open drainage is required for septic hip joints.
  SI joint sepsis is unusual but is best diagnosed
  by physical examination (Flexian Abduction
  External Rotation - FABER most specific) and
  aspiration. A panus (much like in inflammatory
  arthritis) can be seen in tuberculosis
  infections. Late sequellae of septic arthritis
  include soft tissue contractures that can
  sometimes be treated with soft tissues procedures
  such as quadricepsplasty

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• 3. Who gets Osteomyelitis?
• 3.1. Risk Factors
• Presence of foreign materials (PMN defect,
  adhesion of microorganisms)
• Diabetes (microvascular disease, poor wound
  healing, neuropathy)
• Surgery
• Adjacent soft tissue infection
• Peripheral vascular disease
• Sickle cell disease (devitalized bone)
• Congenital defects in phagocyte function

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4. How is the diagnosis of Osteomyelitis
made? 4.1. History and physical
examination presence of risk factors fever,
local pain and tenderness, swelling, decreased
range of motion of a joint, erythema, warmth,
drainage, sinus tracts, ulceration 4.2.
Radiographic diagnosis Routine radiographs
("plain films") fairly specific but appearance
of abnormalities might be delayed (up to 15 days
after symptoms appear) Cortical destruction with
periosteal new bone formation Ex. 1. Salmonella
osteomyelitis of the tibia, began in shaft. See
cortical destruction, new bone formation and
fissure in cortical bone
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• Bone scan
• intravenously injected radioisotope localizes to
  the areas of increased bone activity that occur
  at the site of a bone infection
• very sensitive but has low specificity
• Computed tomography (CT scan)
• 3-dimensional view of affected area - visualizes
  bone, surrounding soft tissue and sequestra
  (islands of dead bone)
• Magnetic resonance imaging (MRI)
• visualizes bone and surrounding soft tissue in a
  3-dimensional fashion
• the appearance of the bone marrow changes due to
  the inflammation associated with the bone
  infection
• test of choice for vertebral osteomyelitis

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• 4.3. Bone biopsy the Gold Standard""
• pathology abundant PMN's, bony necrosis, positive
  gram stain microbiology positive culture confirms
  diagnosis
• 5. What are the major pathogens causing
  Osteomyelitis?
• Pathogens are age specific
• neonates
• S. aureus, group B streptococci
• infants
• eS. aureus, H. influenza
• later in life
• S. aureus predominates
• adults
• Usually S. aureus
• "Mixed infection" (gram positive organisms, gram
  negative aerobes, anaerobes) - in the setting of
  peripheral vascular disease and/or diabetes

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• 6. How is Osteomyelistis treated?
• An individualized treatment plan is often
  necessary
• Treatment often involves medical and surgical
  modalities. Treatment "failures" are frequently
  due to the need for more surgical treatment as
  opposed to more or different antibiotics.

6.1. Medical modalities antibiotics ex.
methicillin-sensitive S. aureus osteomyelitis -
optimal antibiotics are oxacillin /- an
aminoglycoside for synergy treatment is
frequently long-term (for example, 4-6 weeks)
optimization of the management of underlying
conditions such as diabetes
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• Treatment
• What treatment options are available?
• Nonsurgical Treatment
• Antibiotic therapy is the first step in
  treatment.
• The type of antibiotic given depends on which
• bacteria are present. Results are best if
  antibiotics
• are started within eight hours of joint
• infection. Medication is given intravenously
• (directly into blood stream) first for about
• seven days and then orally
• for another two or three weeks.

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6.2. Surgical modalities debridement removal of
nonviable material, including pus, dead tissue
and bone, and foreign material. This removes the
nidus of persistent infection. revascularization
- improving blood flow to the affected areas in
persons with underlying peripheral vascular
disease. This improves wound healing and delivery
of antibiotics to the site. Ablation or
amputation might be necessary to eradicate or
control the infection .
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• After Surgery
• Bed rest is advised for the first 24 hours to
• allow time for inflammation of the synovial
• fluid to resolve. The physical therapist will
• perform and teach family members how to do
• passive range-of-motion (motion performed
• by others) for the entire leg. Movement is very
• important to prevent other joint problems from
• developing.
• More surgery may be needed later if the hip
• loses too much motion or develops deformity
• and/or dislocation. Release of tendons and
• muscles, bone grafts, or reconstruction surgery
• may be needed.
• Long-term follow-up is very important for any
• child who has had septic arthritis. This is true
• even for those children who have had early
• diagnosis, early treatment, and a good result.
• Changes can occur later in the hip with
  degeneration

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