WBR0850
| Author | [[PageAuthor::Mohamed Moubarak, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Emergency Room |
| Sub Category | SubCategory::Infectious Disease |
| Prompt | [[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 mellitus. His 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 thrombosis. Plain 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?]] |
| Answer A | AnswerA::Repeat the x-ray in 2 weeks |
| Answer A Explanation | [[AnswerAExp::Incorrect
Repeat x-ray in 2 weeks will only serve to delay the diagnosis, and it is insensitive before 2-3 weeks]] |
| Answer B | AnswerB::Order an open bone biopsy to confirm the diagnosis |
| Answer B Explanation | [[AnswerBExp::Incorrect
Although bone biopsy is the gold standard in diagnosis of Osteomyelitis, it should be done only when the non-invasive procedures are inconclusive]] |
| Answer C | AnswerC::Continue the antibiotic treatment with no further investigations |
| Answer C Explanation | [[AnswerCExp::Incorrect
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]] |
| Answer D | AnswerD::Order a three phase technetium 99m bone scan |
| Answer D Explanation | [[AnswerDExp::Correct
A three phase technetium bone scan is the diagnostic test of choice for suspected Osteomyelitis if the plain films are negative]] |
| Answer E | AnswerE::Order a MRI scan of the lower extremity |
| Answer E Explanation | [[AnswerEExp::Incorrect
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]] |
| Right Answer | RightAnswer::D |
| Explanation | [[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.
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| Approved | Approved::No |
| Keyword | [[WBRKeyword::Osteomyelitis]] |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
