It feels good to be back! Now, fresh off the inaugural AAPA18 iScan ultrasound event, its only right that my next post is on two of my favorite things- POCUS and infectious disease.
This is a review of 73 patients presenting to an emergency hand clinic (!) over the course of 3.25 years with a pyogenic flexor tenosynovitis. Yep, a whole 22 patients a year… at an emergency hand clinic.
All patients underwent a resident and attending surgeon eval as well as labs including CRP and films. 16 confirmed pyogenic flexor tenosynovitis patients were excluded (these were the slam dunk obvious ones)- while the remaining 57 underwent POCUS while pending labs. POCUS was done by either a resident with 2 years experience in MSK sono, an attending surgeon with sono training, or senior radiologist. Suffice to say, that this isnt exactly us work-a-day EM providers.
Of the remaining 57 patients, there were 29 were ultrasound negative (non-thickened tendon sheath without hyperemia and no peritendonous effusion); all were given PO antibiotics and discharged with every other day follow up until symptom resolution; only one required OR intervention.
Of the 27 patients with positive ultrasound findings- 17 of these had either a positive OR culture or significant purulence seen at the time of OR washout. While this results in a decreased PPV of 63%, and a decreased specificity of 74% – I maintain POCUS is actually much better; keep in mind these numbers do not include the 16 slam dunks on clinical exam. It doesnt take into account the rapid sterilization after a single dose of antibiotics seen in CSF and ascites; nor the 30% negative OR-culture rate seen in other pyogenic flexor tenosynovitis studies. Nor does it take into account that POCUS approaches MRI for sensitivity and specificity in prior studies.
Ultimately, it would be fantastic (and likely better medicine!) if, stateside, we could adopt an ultrasound first strategy (especially with a 97% NPV and 94% sensitivity!). If POCUS negative, patients could get expedited follow up and oral antibiotics. This is pretty much exactly what this group has done. Presumably with this strategy, a small fraction of these more ugly “slam dunk” tenosynovitis cases may not require the OR (the group did not comment on positive OR-culture rates), and the patients in the middle ground could get expedited follow up or overnight observation and serial sonography. It should be noted that “delayed” diagnoses which resulted in poor outcomes were >10 days out from the initiation of symptoms (!); so a day or two may not make much of a difference. This study comes with the usual caveats- there are few MSK ultrasound courses in the USA (I contacted the Jefferson MSK fellowship, no dice for hand sonography!), different equipment than our usual sonosite machines, more training. But that certainly does not mean we can not have something to aspire to.