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|QuestionAuthor={{MM}}
|QuestionAuthor={{MM}}
|ExamType=USMLE Step 3
|ExamType=USMLE Step 3
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|MainCategory=Emergency Room
|MainCategory=Primary Care Office
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease, Infectious Disease
|Prompt=A 55 year-old man comes to ED complaining of fever, pain, and swelling in his right lower leg for the past week.  He was unable to walk for the past 2 days which severely affected his job as a bartender.  He has a past medical history of cardiomyopathy, pace maker implantation for sick sinus syndrome, insulin depended diabetes mellitusHis temperature is 38.9C (101 F), heart rate is 90/minute, blood pressure is 135/80 mmHg, and respiratory rate of 20/minute. Physical examination reveals significant swelling and erythema around the right lower leg.  Ultrasound is negative for deep vein thrombosisPlain x-ray failed to reveal any pathology in his lower extremity.  Blood culture result is bending, and the patient is started on the appropriate antibiotics.  What is the best next step in the management of this patient?
|Prompt=A 55 year-old man comes to the outpatient clinic complaining of progressive severe pain, and swelling in his left leg, which markedly affected his job as a bartender.  The patients said that although he used pain killers, his pain was increasing over the past week.  He is a diabetic patient on MetforminOn examination, the patient is feverish with temperature 39 C (102 F), heart rate 90/min, blood pressure 135/80 mmHg, and respiratory rate of 20/min.   His left leg is severely tender, red, and hot on examinationYou ordered x-ray which turned back with no pathology.  What is the best next step in managing this case?
|Explanation=Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria or mycobacteria. It can be usefully subclassifed on the basis of the causative organism, the route, duration and anatomic location of the infection.  It usually present with fever, chills, erythema, and swelling over the involved bone. 
|AnswerA=Order blood culture then proceed with treatment
|AnswerAExp=Correct


|Explanation=Osteomyelitis is an acute infection of the bone that usually present with fever, chills, erythema, and swelling over the involved bone.  A three phase technetium bone scan is the diagnostic test of choice for suspected Osteomyelitis if the plain films are negative.  It uses technetium 99-m bound to phosphorus as a tracer, which accumulate in the area of increased osteoblast activity, and usually give positive results 2-3 days after the onset of infection.
Although the diagnosis of osteomyelitis is often based on radiologic results showing a lytic center with a ring of sclerosis, blood culture is the first to be done to direct the treatment towards the causative organism
[[File:Bone scan.jpg|300px]]
http://radiopaedia.org/articles/bone-scan
|AnswerA=Repeat the x-ray in 2 weeks
|AnswerAExp=Incorrect


Repeat x-ray in 2 weeks will only serve to delay the diagnosis, and it is insensitive before 2-3 weeks
|AnswerB=Start antibiotic treatment immediately
 
|AnswerB=Order an open bone biopsy to confirm the diagnosis
|AnswerBExp=Incorrect
|AnswerBExp=Incorrect
Antibiotic therapy should be started after blood culture withdrawal


Although bone biopsy is the gold standard in diagnosis of [[Osteomyelitis]], it should be done only when the non-invasive procedures are inconclusive
|AnswerC=Start analgesics and ask the patient to come next week for follow up
 
|AnswerC=Continue the antibiotic treatment with no further investigations
|AnswerCExp=Incorrect
|AnswerCExp=Incorrect
Osteomyelitis is an acute bacterial infection and should be diagnosed and treated with the proper antibiotics


Continue the antibiotics without reaching a diagnosis is in appropriate, and can miss potential complications (e.g. [[abscess]] or gas formation) which may need further management
|AnswerD=It’s a self limiting disease and just need follow up
 
|AnswerDExp=Incorrect
|AnswerD=Order a three phase technetium 99m bone scan
|AnswerDExp=Correct


A three phase technetium bone scan is the diagnostic test of choice for suspected Osteomyelitis if the plain films are negative
Osteomyelitis is not a self limiting disease, and can lead to severe destruction of the bone if left untreated


|AnswerE=Order a MRI scan of the lower extremity
|AnswerE=Order ESR for this patient
|AnswerEExp=Incorrect
|AnswerEExp=Incorrect
ESR is a non specific test and will not help in reaching the diagnosis


[[MRI]] is very accurate in detecting the changes of [[Osteomyelitis]] in early stages, especially in spine and complicated foot Osteomyelitis, but it is Contraindicated in this patient because of the [[pacemaker]] implant
|RightAnswer=A
 
|RightAnswer=D
|WBRKeyword=[[Osteomyelitis]]
|WBRKeyword=[[Osteomyelitis]]
|Approved=No
|Approved=No
}}
}}

Revision as of 16:15, 31 October 2013

 
Author [[PageAuthor::Mohamed Moubarak, M.D. [1]]]
Exam Type ExamType::USMLE Step 3
Main Category MainCategory::Primary Care Office
Sub Category SubCategory::Infectious Disease, SubCategory::Infectious Disease
Prompt [[Prompt::A 55 year-old man comes to the outpatient clinic complaining of progressive severe pain, and swelling in his left leg, which markedly affected his job as a bartender. The patients said that although he used pain killers, his pain was increasing over the past week. He is a diabetic patient on Metformin. On examination, the patient is feverish with temperature 39 C (102 F), heart rate 90/min, blood pressure 135/80 mmHg, and respiratory rate of 20/min. His left leg is severely tender, red, and hot on examination. You ordered x-ray which turned back with no pathology. What is the best next step in managing this case?]]
Answer A AnswerA::Order blood culture then proceed with treatment
Answer A Explanation [[AnswerAExp::Correct

Although the diagnosis of osteomyelitis is often based on radiologic results showing a lytic center with a ring of sclerosis, blood culture is the first to be done to direct the treatment towards the causative organism]]

Answer B AnswerB::Start antibiotic treatment immediately
Answer B Explanation [[AnswerBExp::Incorrect

Antibiotic therapy should be started after blood culture withdrawal]]

Answer C AnswerC::Start analgesics and ask the patient to come next week for follow up
Answer C Explanation [[AnswerCExp::Incorrect

Osteomyelitis is an acute bacterial infection and should be diagnosed and treated with the proper antibiotics]]

Answer D AnswerD::It’s a self limiting disease and just need follow up
Answer D Explanation [[AnswerDExp::Incorrect

Osteomyelitis is not a self limiting disease, and can lead to severe destruction of the bone if left untreated]]

Answer E AnswerE::Order ESR for this patient
Answer E Explanation [[AnswerEExp::Incorrect

ESR is a non specific test and will not help in reaching the diagnosis]]

Right Answer RightAnswer::A
Explanation [[Explanation::Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria or mycobacteria. It can be usefully subclassifed on the basis of the causative organism, the route, duration and anatomic location of the infection. It usually present with fever, chills, erythema, and swelling over the involved bone.

Educational Objective:
References: ]]

Approved Approved::No
Keyword [[WBRKeyword::Osteomyelitis]]
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