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* An 8-year-old boy
  radius01 - 02/06/09 19:01
  with sickle cell disease presents with left leg pain and a high fever. He has been refusing to walk since yesterday. On physical examination, his temperature is 39.8 C (103.6 F), blood pressure is 122/68 mm Hg, pulse is 102/min, and respirations are 20/min. His left femur is tender to palpation 3 cm above the left knee, and there is marked soft tissue swelling. A plain film of his left leg is normal. A bone scan shows increased uptake around the metaphysis of the left femur. Which of the following is the most likely pathogen?
A. Escherichia coli
B. Haemophilus influenzae
C. Salmonella
D. Staphylococcus aureus
E. Streptococcus pneumoniae
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* Re:An 8-year-old boy
  kiranraja - 02/06/09 19:13
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* Re:An 8-year-old boy
  john2007 - 02/06/09 19:17
  uw 2009 says:
it adds: this is hy and contraversy, but consider salmonella for sickle cell om all the time.
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* Re:An 8-year-old boy
  radius01 - 02/06/09 19:30
  I chose c too but the given ans is d.
The correct answer is
D. Osteomyelitis is a pyogenic infection of the bone. The pathogenesis of the disease is similar to septic arthritis, with the origin of infection occurring from hematogenous spread, direct extension of a local infection, or direct inoculation of bone either from trauma (e. g. , puncture wound or open fracture) or surgical manipulation. In children, the most frequent presentation is acute hematogenous spread. The most common location of osteomyelitis is the metaphysis of the distal femur and proximal tibia. The most prevalent pathogens are the same as those seen in septic arthritis. Staphylococcus aureus is the most common pathogen, with group A beta-hemolytic streptococci a distant second. Neonates are at risk for group B beta-hemolytic streptococci. Haemophilus influenzae may occur in infants and young children, but it is not seen as frequently as in septic arthritis. In addition, children with H. influenzae osteomyelitis usually have fever and concomitant joint infection. Patients with puncture wounds of the foot are susceptible to Pseudomonas aeruginosa osteomyelitis. Patients with sickle cell disease are at risk for infection by Salmonella and other gram-negative bacteria, and patients in the 18- to 48-month age range are at increased risk for acute recurrent Salmonella osteomyelitis. Salmonella osteomyelitis frequently involves multiple sites and creates punched-out destructive lesions of the metaphysis and diaphysis. However, even in patients with sickle cell disease, Staphylococcus aureus is still the most common pathogen for osteomyelitis. Most patients with osteomyelitis will present with a chief complaint of fever and bone pain. The pain is usually severe, constant, and aggravated by motion. The older the child, the more exquisite the point tenderness, because the bone has a thicker metaphyseal cortex with a dense fibrous periosteum. Localized swelling, warmth, and erythema are signs seen late in the infection, as the periosteum becomes more involved. Neonates can present with vague symptoms, consisting only of irritability and poor feeding, or can show signs of fulminant sepsis. The peripheral white blood cell count may be normal, or elevated with a left shift. The erythrocyte sedimentation rate (ESR) is usually elevated, and blood cultures are positive in approximately 60% cases. Bone cultures taken either surgically or by needle aspiration result in a culture yield of 80%. Plain radiographs may be normal for up to 2 weeks from the onset of illness, and the earliest signs on plain films are soft tissue swelling and displacement of muscle plane. Bony changes begin to appear by 7-10 days, starting with a hazy appearance of the metaphysis followed by irregular areas of trabecular necrosis and absorption. Eventually, subperiosteal new bone formation occurs as the infection spreads through the cortex. A bone scan usually diagnoses osteomyelitis as early as 24-48 hours from onset. Treatment should begin with empiric parenteral antibiotics. The selection of antibiotic should include coverage of Staphylococcus aureus, as well as other organisms; the agent can probably be based on the patient's age and history of illness. Surgical debridement may be necessary if pus is present on needle aspiration, or if evidence of either joint involvement or abscess is present.
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* Re:An 8-year-old boy
  john2007 - 02/06/09 19:31
  is ths uw q?? i got the same uw q with above explanations !!!  
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* Re:An 8-year-old boy
  radius01 - 02/06/09 21:34
  No these qs I was told to be kaplna qs.I am not sure though.u can even get the score at the end of each set of qs.  
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