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Category: Infectious Disease

HOW TO DIAGNOSE SEPTIC ARTHRITIS

HOW TO DIAGNOSE SEPTIC ARTHRITIS

The biggest challenge in diagnosing septic arthritis is to think of it. Once you think of it, there is a diagnostic process that you activate. The second biggest challenge is that that diagnostic process we learn in training is flawed. We have no alternatives right now, so I will share with you my thoughts on how we should use our judgment as clinicians.   Triggers to consider septic arthritis essentially are the same triggers as infection anywhere. Celsus’ cardinal signs…

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DENGUE FEVER: SIGNS OF CAPILLARY FRAGILITY

DENGUE FEVER: SIGNS OF CAPILLARY FRAGILITY

A patient presents with a rash and fever after recent travel to Bolivia. She was there for one week and returned 3 days ago. She took her antimalarial medication, so could this be dengue fever? Fever in the returning traveler relies on Bayesian thinking. We start with probabilities based on endemic diseases and then the history and physical examination raises or lowers the probability of each. In this case malaria was prevented with doxycycline, so dengue fever is more likely….

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CELLULITIS: DON’T JUST LOOK – FEEL!

CELLULITIS: DON’T JUST LOOK – FEEL!

  Cellulitis, when you think about it, is probably not the most helpful term. Literally, it means “infection of cells.” What cells? The anatomical area is actually the dermis, as well as the subcutaneous tissue.   A patient presenting with “dermitis” has a lesion that is clearly confined to the skin. A patient presenting with significant edema has involvement of subcutaneous tissues. These are the patients where we need to consider the surgical diseases: necrotizing fasciitis, pyomyositis, and abscess.  …

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HOW TO PALPATE FEVER

HOW TO PALPATE FEVER

Most studies say that palpation of fever is inaccurate. I am not so sure. Many of the studies use oral temperature as a gold standard, which of course can be as low as 50% sensitive for true fever. These studies conclude that the mothers’ palpation over-called the diagnosis but I wonder whether rectal temperature assessment would not have proven many mothers to be correct.   I see people put their palm on the forehead to check for fever, and then…

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FEVER: ORAL TEMPERATURE HAS LIMITED SENSITIVITY

FEVER: ORAL TEMPERATURE HAS LIMITED SENSITIVITY

A patient presents with headache. The history and physical examination do not reveal the cause. You take a second look at the vital signs.  Oral temperature is 99.3.  You have the nurse check the rectal temperature. It is 101.9. What is the sensitivity and specificity of oral temperature for fever?   There are numerous studies on this topic, and unfortunately, the populations studied are far too heterogenous to truly give a range for sensitive and specificity. In some studies the…

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FEVER OF UNKNOWN ORIGIN

FEVER OF UNKNOWN ORIGIN

In emergency medicine we occasionally encounter fever that won’t yield to a specific diagnosis. We speculate a viral cause and a self-limited course, but it is worth thinking through the next step. The term “fever of unknown origin” originates in internal medicine and refers to specific criteria that are appropriate for that setting. If the fever lasts three weeks, it is not necessarily consistent with a self-limited viral cause and this thought process is triggered. Classic causes of fever of…

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BOTFLY: OCCLUSION TEST

BOTFLY: OCCLUSION TEST

A patient recently presented with a subcutaneous nodule that appeared to be an abscess.  It was raised, erythematous, tender, indurated, and had a central plug…wait, no, it had a central hole.  And he just got back from Belize.  We put a transparent membrane on it to see if there was a creature in there.  Sure enough, a snout pushed at the membrane, seeking air.  This established the diagnosis – myiasis, secondary to a bot fly bite. Trying to remove that…

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OSTEOMYELITIS IN THE CHRONIC WOUND

OSTEOMYELITIS IN THE CHRONIC WOUND

A patient presents with a chronic diabetic heel ulcer that has worsened over the past few weeks.  Could this be osteomyelitis? It turns out that physical examination findings can significantly raise or lower the probability of this diagnosis. According to JAMA’s rational clinical examination series (Butalia 2008), 2 findings on physical examination have more powerful likelihood ratios than MRI: -A crater breadth of 2 square cm or more has a positive LR of 7.2. -Probing to bone has a positive…

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