USMLE Forum Archives - USMLE Step 1 - lef50
lef50
babbu5508 - 05-01-11 00:25
A 2 1/2-year-old boy is brought to the emergency department by his parents because he is has stopped bearing weight on his right lower
extremity. His parents report that he has been irritable for the last 12 hours and started limping 6 hours ago. He now refuses to put any weight
on the affected leg. They also report a low grade fever for the past 24 hours. On physical examination, his temperature is 39.1 C (102.4 F). The
child is lying with his right hip slightly flexed, externally rotated, and in abduction. He does not allow any passive motion of his hip. Laboratory
studies reveal a white blood cell count of 14,000/mm3. The erythrocyte sedimentation rate is 58 mm/hr. X-ray films of the right hip and pelvis
are normaI.
If the patient was had not received any scheduled immunizations, which of the following would be the most likely pathogen?
babbu5508 - 05-01-11 00:25
A 2 1/2-year-old boy is brought to the emergency department by his parents because he is has stopped bearing weight on his right lower
extremity. His parents report that he has been irritable for the last 12 hours and started limping 6 hours ago. He now refuses to put any weight
on the affected leg. They also report a low grade fever for the past 24 hours. On physical examination, his temperature is 39.1 C (102.4 F). The
child is lying with his right hip slightly flexed, externally rotated, and in abduction. He does not allow any passive motion of his hip. Laboratory
studies reveal a white blood cell count of 14,000/mm3. The erythrocyte sedimentation rate is 58 mm/hr. X-ray films of the right hip and pelvis
are normaI.
If the patient was had not received any scheduled immunizations, which of the following would be the most likely pathogen?
The correct answer and explanation will be available after you answer.
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#3
Re: lef50
babbu5508 - 05-15-11 03:52 My answer is: c.
The correct answer is C. Hemophilus influenzae in the past has been the most common cause of septic hip arthritis in children 3 months to 3 years of age. However, with the advent of H. influenzae type B vaccines in the late 1980's, the incidence of infection secondary to Hemophilus influenzae has dramatically decreased. Children who are not immunized are at increased risk for Hemophilus influenzae. The other organisms are causes of septic arthritis, but are not the most common cause in an unvaccinated 2-year-old
#8
Re: lef50 babbu5508 - 06-21-11 00:54 Infants and toddlers should receive four total doses of the HiB vaccine. One dose should be given at each of the following ages:
2 months
4 months
6 months
12-15 months
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