joints, kidneys and minimal tsh

Yesterday we discussed approach to a patient with a single angry joint. 

Although the history and physical exam is crucial, there are no physical exam findings that reliably rule in or out septic arthritis according JAMA Rational Clinical Exam paper linked HERE.

For the Joint aspirate:

WBC over 100,000- Positive LR 28

WBC over 25,000- Positive LR 2.9

WBC less than 25,000- Negative LR 0.32

PMN over 90%- Positive LR 3.4; Negative LR 0.34

This isn't perfect either. 

◦    The absolute leukocyte count can be used to differentiate inflammatory from non-inflammatory fluid; however, it cannot be used to differentiate between inflammatory conditions, such as septic arthritis and crystal arthropathy!

◦    Traditional teaching suggests that cell counts greater than 50,000 WBC/mm3 are indicative of septic arthritis. THIS IS NOT TRUE! Crystal arthropathies and rheumatic disorders may present with cell counts this high.

AND septic arthritis may have cell counts < 50,000 WBC/mm³

Polymorphonuclear cell (> 90%) suggests the presence of an inflammatory condition, regardless of the total cell count!!

Also, the culture and sensitivty aren't perfect either.

Gram stain: sensitivity is  75%; Culture up to 90%

--> A special thanks to Dr. Ali Kara for discussing a case of AKI this morning. Click here for a NEJM CPC that goes over the approach to ARF

-->Although we didn't talk about it today, a patient was admitted last night with thyroid storm.
Here is a previous post on Thyrotoxicosis, with a good article on thyroid emergencies.