Osteomyelitis and Septic Arthritis Flashcards

1
Q

What is Osteomyelitis?

A

An inflammation or swelling of the bone tissue due to an infection
Can be Acute or Chronic
Can be:
1. Pyogenic (Suppurative)
Producing pus
Typically, bacterial
Acute or Chronic

  1. Non-Pyogenic (Non-Suppurative)
    Fungal osteomyelitis
    Skeletal syphilis
    Tuberculous osteomyelitis
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1
Q

What is Pyogenic (Suppurative) Osteomyelitis?

A

Producing pus
Typically, bacterial
Acute or Chronic

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2
Q

What is Non-Pyogenic (Non-Suppurative) Osteomyelitis?

A

Fungal osteomyelitis
Skeletal syphilis
Tuberculous osteomyelitis

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3
Q

What may cause Osteomyelitis?

A
  1. A bacterial (Staphylococcus aureus) bloodstream infection
    - M/c in infants and children
    - affects long bones
    - Femur > Tibia > Fibula
    - Distal end > Proximal end
    - In adults it involves the vertebral bones along the spinal column
  2. A nearby infection due to
    - a traumatic injury
    - frequent medication injections
    - a surgical procedure
    - Diabetic patients who develop foot ulcers
  3. Low immune system
    - e.g Sickle cell disease or HIV
    - immunosuppressive medications (e.g. chemotherapy or steroids)
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4
Q

Where abouts in the bone does osteomyelitis affect an infantile?

A

<8 months
neonates:metaphysis and/or epiphysis

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5
Q

Where abouts in the bone does osteomyelitis affect a child?

A

1 year to closure
metaphysis

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6
Q

Where abouts in the bone does osteomyelitis affect a child?

A

epiphyses and subchondral regions

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7
Q

What is the epidemiology of Osteomyelitis?

A
  • M/C in younger children (2 – 12 years old)
  • Can occur at any age.
  • M/C in males than females
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8
Q

What are the signs and symptoms of Osteomyelitis?

A
  • Fever
    - Fatigue
    - Pain and tenderness in the affected area
    - Feeling unwell and irritability in infants who can’t express pain
    - Swelling, warmth and redness of the affected area
    - Difficulty moving joints near the affected area
    - Difficulty bearing weight or walking
    - A new limp
    - Stiffness (with vertebral involvement)
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9
Q

What are the DDX of Osteomyelitis?

A
  • Neuropathic osteoarthropathy
    - Aseptic arthritis
    - Acute fracture
    - Recent surgery
    - Ewing’s sarcoma
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10
Q

What is treatment and Management for Osteomyelitis?

A
  • Medications
    - Intravenous (IV) or oral antibiotics
    - Monitoring of successive X-rays and blood tests
    - Pain management
    - Bed rest
    - or restricted movement of the affected area
    - Surgery
    - may be necessary to drain infectious fluid, or to remove damaged tissue and bone
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11
Q

What are the complications of Osteomyelitis?

A

Complications:
- In untreated cases, Osteomyelitis becomes chronic with eventual formation of:

  1. Sequestrum
    - Devascularisation of a portion of bone with necrosis and resorption of surrounding bone leaving a floating piece (Segment of dead/ necrotic bone)
    - Develops after 30 days
    - In some cases – sequestrum becomes encased in a thick sheath of periosteal new bone (Involucrum)
    - May reside within marrow for long period
  2. Involucrum
    - Layer of living bone (bony collar or cloak) around necrotic bone as attempt to wall off infective process
    - Thick sheath of periosteal new bone surrounding a sequestrum
    - Laminated or spiculated periosteal reaction
    - Develops after 20 days
  3. Cloaca
    - space in which dead bone resides
    - Associated with chronic osteomyelitis

Complications:
- Other complications of Chronic Osteomyelitis include:

  1. Brodie’s Abscess
    - Lucent, well-defined lesion with thick sclerotic rim
    - Lucent tortuous channel extending towards growth plate prior to physeal closure
    - Typically, in metaphysis or diaphysis of long bones:
    - thick and dense cortex
    - sinus tracts to skins
  2. Fibrosarcoma
  3. Squamous cell carcinoma
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12
Q

What are radiological findings of Osteomyelitis?

A
  1. Soft tissue Swelling
    - Earliest Sign
    - Often in metaphyseal region
    - Loss or blurring of normal fat planes
  2. Cortical loss
    - Bone destruction (Bony lysis)
  3. Periostitis
    - Periosteal reaction or thickening – laminated, solid, codman’s triangle
    - May appear aggressive
  4. Endosteal scalloping
  5. Loss of trabecular bone architecture
  6. Peripheral sclerosis
  7. Poss effusion in an adjacent joint
  8. Regional Osteopenia

Chronic Osteomyelitis
- Sclerosis
- cortical thickening
- Periosteal new bone formation
- Destruction
- sequestra

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13
Q

What is septic arthritis?

A

A destructive arthropathy caused by an inflammation due to hematogenous seeding of the synovial membrane from an intra-articular infection e.g.
- infected source elsewhere in the body (wound infection)
- direct, contiguous extension from osteomyelitisadjacent to the joint
Early imaging is necessary to:
- detect any joint effusion due to an intra-articular infection
- check for any associated osteomyelitis
Subdivided into:
1. pyogenic (septic) arthritis
- due mostly toStaphylococcalandGonococcalorganisms
- HALLMARK: destruction of the articular cartilage and long, contiguous segments of the adjacent articular cortexfrom proteolytic enzymes released by the inflamed synovium.
2. non-pyogenic arthritis
- due mostly to infection withMycobacterium tuberculosis

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14
Q

What is the epidemiology of septic arthritis?

A
  • All age groups
    - 50% <3 yoa
    - M = F
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15
Q

What are the clinical findings of septic arthrits?

A
  • M/C affected joint = KNEE
    - Most prone to bacterial infection due to abundant blood supply to the metaphysis
    - Other joints may be affected e.g. shoulder and hip
16
Q

What is the most commonly affected joint for septic arthritis in infants?

A

Hip

17
Q

What is the most commonly affected joint for septic arthritis in children?

A

Knee

18
Q

What is the most commonly affected joint for septic arthritis in adults?

A

Large joints

19
Q

What is the most commonly affected joint for septic arthritis in IVDU?

A

Sacroiliac joint

20
Q

What are the signs and symptoms of septic arthritis in infants?

A

Refusal to feed
Irritable
Failure to thrive
High/no fever
Hypothermia
Joint swelling
Decreased active and passive ROM
Deformity at joint

21
Q

What are the signs and symptoms of septic arthritis in children?

A

Fever
Chills
Rigors
Toxemia
Tachycardia
Tachypnea
Febrile convulsions
Severe pain
Joint swelling
Deformity
Pseudoparalysis with extremely painful ROM

22
Q

What are the signs and symptoms of septic arthritis in adults?

A

Pre-existing arthritis
RA
Trauma
Fever
Tachycardia
Severe pain
Joint swelling
Deformity
Extremely painful ROM
Muscle spasm

23
Q

What are the causes of septic arthritis?

A
  • Bacterial (staptylococcus aureus, E.Coli, proteus and streptococcus )
    - Viral
    - Fungal
24
Q

What are the risk factors of septic arthritis?

A
  • Advanced age (>80 yoa)
    - Immunocompromised state
    - Rheumatoid Arthritis
    - Intra-articular or steroid injections
    - Prosthetic joints
    - Intravenous Drug Abusers
    - Joint trauma including surgery
    - AIDS
    - Diabetes Mellitus
25
Q

What are the DDX of septic arthritis?

A
  1. Osteomyelitis:
     - may mimic septic arthritis in its presentation
     - Ultrasonography
                		– helps exclude the presence of joint effusion thus suggesting contiguous septic arthritis
     - Dx confirmed on a bone scan.
  2. Transient synovitis:
     - benign synovial inflammation with subsequent effusion formation
     - more common than septic arthritis 
                                    HOWEVER
     - septic arthritis is considered as a primary pathology until proven otherwise because of its catastrophic outcomes as compared to transient synovitis, which is a self-limiting condition
26
Q

What is the treatment/management of septic arthritis?

A
  1. Antibiotics
  2. Adequate drainage of the joint
    - Arthroscopic drainage
    - Open drainage in difficult and deep joints
  3. Needle aspiration
  4. Monitoring of synovial fluid leukocyte counts and cultures
  5. Acute phase of the disease
    - rest and optimal joint position
  6. Following the acute phase
    - early physical therapy
    - aggressive mobilization
27
Q

What are the complications of septic arthritis?

A
  • Bone and cartilage destruction
    - Osteonecrosis (E.g. Avascular necrosis of the femoral head)
    - Secondary osteoarthritis
    - Osteomyelitis
    - Eventually Ankylosis
    - Relapses or reinfections
    - Avascular necrosis of the femoral head
28
Q

What are the radiological findings of septic arthritis?

A
  • Earliest findings:
    - may be normal in the very early stage of the disease
    - displaced joint capsule (Waldenstrom’s sign in hip)
    - Loss of normal subchondral bone (osseous sign) – “white line”
    - Joint effusion may be seen
    - Juxta-articular due to hyperaemia
    - Joint space narrowing due to cartilage destruction in the acute phase
    - Medullary, motheaten destruction may occur if process continues
    - Reactive juxta-articular sclerosis and ankylosis in severe cases - if left untreated
    Althoughconventional radiographs areobtained as the initial study, they arerelatively insensitiveto the early findings of the disease except for soft tissue swelling and osteopenia.
29
Q

What is the advanced modalities for septic arthritis?

A
  1. Computed Tomography (CT)
    - Delineation of soft tissue extent
    - Monitoring of percutaneous biopsy
    - May reveal sequestra, cloaca & soft tissue abscess
  2. MRI
    - Inflammatory response leads to H2O accumulation in marrow ->
    - Decreased Signal Intensity (SI) on T1 and increased on T2
30
Q

What are the differences between osteomyelitis vs septic arthritis?

A

Osteomyelitis and septic arthritis both:
- rare and serious conditions
- usually caused by the bacteriumStaphylococcus aureus

Osteomyelitis - infection of the bone

Septic arthritis - inflammation in the surface of the cartilage that lines the joint and the synovial fluid that lubricates the joint that is caused by an infection.