I. Pathophysiology/Epidemiology

  1. Us. source of bug is bacteremia (although can have subsided already); can also be direct spread or traumatic implantation
  2. Metaphysis is most common site because of its sluggish blood flow
  3. Peak age 2-5y
  4. Bugs: Staph Aur. (75%), H. Flu, Pneumococcus; also Candida; in neonates, Gp. B Strep; in sicklers, Salmonella.

II. Clinical presentation:

  1. Pain, musc. spasm
  2. Us. no true limitation of ROM, unlike septic arthritis
  3. High WBC may or may not be present
  4. Usually have positive blood cx
  5. Complications:
  1. Can have fulminant course in neonates (presents as soft tissue swelling & decreased spont. motion)
  2. Spread to marrow cavity, get more pain & limited ROM
  3. Bone infarction (us. in chronic osteo)
  4. Extension to & necrosis of growth plate

III. Dx:

  1. Radionucleide bone scan (Tc, Ga, In) 90% sens
  2. Blood Cx
  3. XRay--only shows late changes