Outpatient Diagnostic Arthrocentesis

[ColonelForbin]

I'm a relatively new IM trained PCP. One of the clinical scenarios I still find myself struggling with is acute monoarticular arthritis. Given that it is very difficult to differentiate clinically between non-septic (i.e. Gout, Pseudogout, etc.) and septic causes, I'm wondering what factors others use to help decide who needs referral to ED for urgent arthrocentesis with empiric antibiotics while results are pending versus less urgent outpatient arthrocentesis with results available the next day and no empiric antibiotics.

Not thinking so much about 1st MTP joint, which I think many are comfortable treating empirically as Gout. Thinking more about the knee, wrist, etc. I'm also thinking more about the borderline cases with no or low grade temp, moderate pain, moderate inflammation, etc. High fever, severe pain, or rapidly progressive symptoms to me is clearly ED.

I have also seen patients with recurrent acute monoarticular arthritis in the knee with known prior Gout history get treated empirically for Gout with flares upon presentation to the ED without arthrocentesis to confirm. I can see both sides of this, although the idea of missing the episode that is septic and not actually Gout seems like a potential issue.

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[Animalcules]

Any acute monoarticular arthritis as you describe is septic until proven otherwise. 1st MTP and right context sways the odds significantly to gout of course, but I have also seen septic arthritis of this joint. With a prior history of gout or pseudo gout, recurrent involvement of a specific joint, and no red flags, it is okay to treat empirically as such, but any uncertainty should be tapped.

 

[RheumDoc112]

I'm just happy to see you said arthrocentesis for both of your two options. Rule of thumb: failure to aspirate prepare to litigate.
In general, acute monoarticular arthropathy should be assumed infectious until proven otherwise.
A few details that can help you differentiate further:
-History of IVDU or recent infection anywhere-->think infection
-Prior episodes-->likely crystal vs other systemic rheumatologic syndrome (unless they're the most unlucky person on the planet)
-Constitutional--> can be either, but if mild consider spondyloarthropathy associated (missed all the time by the primary team that calls me)
-This should go without saying but look for any area that an infection could seed, scrape in proximity-->think infection

None of this is gospel and eventually, you'll get a good feel for the whole emergent vs non-emergent differentiation. And if all else fails, better safe then sorry and send them to the ED.
Good luck!

 

[fooli_doc]

I tend to lean on the history and how the joint and patient look. If the joint is angry/red/swollen or the patient has fever etc, its going to be ED everytime. They simply have the lab sophistication to get it diagnosed in a quick fashion and start potential treatment that I can't do anyway (IV antibiotics, emergent ortho consultation). I will say its rare that I actually see a joint fit this board question-style description in the primary care setting. Usually its a little more slowly progressive swelling and aching, without any major constitutional symptoms. If its a joint I'm comfortable aspirating, I'll do it non-emergently and follow up with them closely.

 

[Redpancreas]

I'm a relatively new IM trained PCP. One of the clinical scenarios I still find myself struggling with is acute monoarticular arthritis. Given that it is very difficult to differentiate clinically between non-septic (i.e. Gout, Pseudogout, etc.) and septic causes, I'm wondering what factors others use to help decide who needs referral to ED for urgent arthrocentesis with empiric antibiotics while results are pending versus less urgent outpatient arthrocentesis with results available the next day and no empiric antibiotics.

Not thinking so much about 1st MTP joint, which I think many are comfortable treating empirically as Gout. Thinking more about the knee, wrist, etc. I'm also thinking more about the borderline cases with no or low grade temp, moderate pain, moderate inflammation, etc. High fever, severe pain, or rapidly progressive symptoms to me is clearly ED.

I have also seen patients with recurrent acute monoarticular arthritis in the knee with known prior Gout history get treated empirically for Gout with flares upon presentation to the ED without arthrocentesis to confirm. I can see both sides of this, although the idea of missing the episode that is septic and not actually Gout seems like a potential issue.

Fever, trauma hx, monoarticular, immunosuppressed and I would refer to the ED for the tap unless you're comfortable with the tap right there and following up on results after PM clinic. I would never ONLY treat empirically for gout unless the history's very clear (prior attacks in that area, etc. with no risk factors/hints for SA) in today's litiginous society and even then would recommend an outpatient tap and give clear instructions to come back to the ED if things get worse in the next 48 hrs. The patient may then opt to go to the ED now to get the tap at which point I'd say OK and be done with it.