Brown Ultrasound Tape Review: 9:24:2015
ARTICLE #1 – Suddenly, painlessly blind? Keep calm and get the Ultrasound.
Vrablik et al. The Diagnostic Accuracy of Bedside Ocular Ultrasonography for the Diagnosis of Retinal Detachment: A Systematic Review and Meta-analysis. Annals of Emergency Medicine 2014; 20: 1-6.
In this systematic review, Vrablik et al assessed the diagnostic accuracy of ED Ocular US for retinal detachment. They whittled 7771 unique citations down to 4 trials that included a total of 201 ED patients, where EUS Dx was compared to Ophthalmologic evaluation and/or Orbital CT. Prevalence was 15-38%, sensitivity and specificity of EUS were 97-100% and 83-100%, respectively.
This modality may be helpful because 1) vision-threatening complaints are time sensitive, 2) formal dilated fundoscopic exam may be impractical or impossible in the busy ED setting, and 3) formal Ophtho consultation may be limited or unavailable in some EDs. These studies were small and participating physician training was variable, but results showed that we can reliably make this diagnosis in the ED with a linear array probe.
We discussed distinguishing retinal detachment from vitreous hemorrhage or vitreous detachment (keeping in mind these are not mutually exclusive). Retinal detachment classically presents as sudden, painless, monocular visual impairment, like “looking through a curtain.” EUS will show the “sail sign”, a funnel shaped, sharply defined, reflective, linear membrane anchored to the optic disc and waving serpiginously as the patient moves their eyes. In vitreous detachment the patient may describe “floaters” or “flashes of light” that move with eye movement, and EUS will show the “seaweed sign”: fine, granular, swirling echogenic debris in the posterior eye, with no tethering to the disc.
ARTICLE #2 – To incise, or not to incise, that is the question.
Squire et al. ABSCESS: Applied Bedside Sonography for Convenient Evaluation of Superficial Soft Tissue Infections. Academic Emergency Medicine 2005; 12(7): 6011-607.
This study investigated the utility of EUS in detecting subcutaneous abscesses in 107 patients with presentations concerning for cellulitis vs abscess. Residents and Attendings who had received a 30min training session were eligible, and their Clinical and EUS diagnoses for “+/- abscess” were compared to +/- pus with I&D, or +/- antibiotic failure at 7 day follow up (failure meaning most likely it was an abscess).
Interestingly, there were 18 cases where EUS and Clinical Dx disagreed, and EUS proved correct in 94% (n=17) of them: 9 of the negative Clinical Dx cases (23%) became positive with EUS, and 9 of the positive Clinical Dx cases (13%) became negative with EUS. Many of the ED sonographers also discovered nerves and vessels, which changed management…most significantly for 4 of the falsely positive Clinical Dx patients, of whom 3 had hematomas and 1 had an aneurysm (#whoathatwasclose). But while the investigators did prove that EUS can more accurately identify abscesses, they did not report any patient-centered outcomes, such as less antibiotic use, faster recovery, fewer complications, fewer return visits, or less recurrence. So in summary, it remains to be seen whether the findings here should definitely change practice at this time.
We also reviewed the EUS-for-abscess technique: with the linear probe placed on the skin, an abscess will appear as a hypoechoic heterogeneic mass, generally spherical with ill-defined borders, and with variable internal echoes (pus) that will “swirl” with compression. Cellulitis is generally more hyperechoic and more uniform.
BROWNsound BONUS: TAPE REVIEW RAPID FIRE!
– Achilles Tendon rupture: appears as a defect with surrounding hypoechoic hemorrhage
– B lines (lung US):
1) must obliterate the A lines
2) must be linear
3) must go 18cm deep
4) must be persistent
5) must be more than 3 per zone
6) must be more than 2 rib spaces per side to support HF
1) must be non-compressible
2) must be a blind-ended pouch
3) must be tender-to-palpation
4) must be 6mm outside-to-outside to be “too big”
– Tamponade: RV must collapse during diastole
1) In the sagittal view the bladder apex correlates with the cervix, which may helps avoid confusion between the vagina and the endometrial stripe
2) Key cutoff: fluid tracking <2/3 up the uterus (in the caudal direction) may be physiologic; >2/3 is more likely pathologic