Part of our new conference schedule is doing a quick 5 minute summary on a journal article of interest, EKG from the past week, and Xray. The idea being that by the end of the year, we will have roughly covered 40 journals, EKGs, and Xray Topics.
Today’s 5 minute journal was performed by the great resident, Dr. Bill McDowell, who absolutely crushed it.
I think this is a great article to review as we see abscesses frequently, and it somewhat becomes humdrum in the ED. Abscesses are also fraught with debate on who should receive antibiotics vs. I+D alone. The main takeaways from this article are below.
— Historically, I+D by itself has an approximate 84% cure rate
— Many small previous studies showed no difference in cure rates of I+D alone vs. I+D with antibiotics
— One prior large study (Talan et al, 2016) found superior cure rates with Bactrim/I+D vs. placebo/I+D (80.5% vs. 73.6% cure rate).
— Clinical Question: Do antibiotics with anti-MRSA activity improve cure rates for abscesses when given following I+D?
— Study Type: Multicenter, prospective, randomized, double-blind, placebo-controlled clinical trial (superiority design)
— Study Groups: 10-day courses of Clindamycin vs. Bactrim vs. Placebo (following standard I+D)
— Inclusion Criteria: single abscess <5cm diameter, age>6 months, 1 day of 2 or more symptoms (erythema, swelling/induration, local warmth, purulent drainage, tenderness)
— Exclusion Criteria: BMI>40, immunocompromised (including diabetes, chronic renal failure), immunosuppresive therapy, SIRS criteria present, Temp>38.5C, human/animal bite, site requiring specialist (genitalia, perirectal, hand), anti-staphylococcus antibiotic in past 14 days, requires admission, resident of long-term care facility, major surgery in past 12 months
— Primary Outcome Being Tested: Clinical Cure. “Lack of Clinical cure” was defined as: continued signs/symptoms, occurrence of skin infection at new body site, reoccurrence at original site, inability to take entire course of antibiotic secondary to adverse side effects, hospitalization related to infection, or unplanned surgical treatment of infection
— Study Population: 786 patients (36% peds). 343 patients fully adherent to antibiotic 10-day course. Average surrounding area of erythema 27.4 cm² (~5×5 cm)
— Cure rates: clindamycin: 83.1%, Bactrim: 81.7%, Placebo: 68.9%
(Statistical significance for antibiotics vs. placebo). No statistical
signifance between bactrim vs. clindamycin
— Most failures due to new lesion at other site or use of rescue
medication- especially in placebo group
— Rates of Diarrhea: Clindamycin 21.9%, Bactrim 11.1%, Placebo 12.5%
— Study population had large surrounding erythema suggesting large
percentage of co-associated cellulitis
— Antibiotics have a clinically significant higher cure rate compared to placebo. However, this study population had a relatively large surrounding area of erythema, which makes it unclear whether the antibiotics were treating the abscess itself or the co-associated cellulitis. Furthermore, it appears the advantage of antibiotic use in these patients was in preventing occurrence of an abscess at a separate site, which suggests the antibiotics main function was in clearing MRSA recidivism in this patient population vs. the actual treatment of the original skin infection.
— Although there was no statistical difference in cure rates between Bactrim and Clindamycin, it does appear to be advantageous to prescribe Bactrim vs. Clindamycin as was associated with fewer side effects–mainly rates of diarrhea (Clinda 21.9% vs. Bactrim 11.1%)
— Abscess treatment has evolved greatly over the last decade with several studies performed during this time. RebelEM provides a great summary of this research (RebelEM Abscesses). I also love this review because it refers to some amazing work by our own RUSH staff including Dr. Gottlieb and Dr. Hallock as well as our always consulted pharm team including Josh DeMott and Gary Peska (Annals of EM Link)
The 5-minute EKG was presented by our fan-favorite attending, Dr. Patwari. See EKG below (Answer to follow)
As always, it is important to approach an EKG in a systematic way including rate, rhythm, axis, intervals, and segments. However, the big takeaway from this EKG is that it is a Regular Narrow-Complex Tachycardia with HR roughly 150. Now we just need to decide which type of Regular Narrow-Complex Tachycardia. This should lead us to a differential including Sinus Tachycardia, SVT (AVNRT vs. AVRT), and Atrial Flutter. You could also consider Atrial Ectopic Tachycardia (more commonly seen in peds), however, it is a rarer diagnosis compared to above.
Drumroll… This is Atrial Flutter. Clues to this are the saw-tooth appearance caused by the flutter waves, HR of roughly 150, and P waves that march out at a rate of roughly 300.
Atrial Flutter Basics
— Type of supraventricular tachycardia caused by re-entry circuit within the right atrium
— Since it originates from the atria, the heart rate will resemble the atrial rate, most often ~300 bpm (though there can be variability person-to-person with average range 250-350)
— The AV node acts as the electrical gateway between the atria and ventricle, and has long refractory period allowing it to “block” excessive depolarizations from the atria
— This most often leads to a 2:1 AV ratio block meaning for every two P waves produced, a QRS will form (as seen above) which often produces a ventricular rate (QRS) of HR roughly 150.
— If there is a higher-degree block (e.g. from medications or underlying heart disease), you can see a 3:1 or 4:1 block, which corresponds to the number of P waves prior to the QRS. This also gives a much better “saw-tooth” appearance which we remember from our Med School rhythm strips seen in FirstAid (as below)
— If we confused the first EKG with SVT, and gave adenosine (AV nodal blocking agent), we would see the continuation of flutter waves, but no QRS depolarizations due to the AV nodal blocking properties of adenosine (seen in EKG below). The good news is that adenosine only lasts 10-15 seconds, and ventricular contractions will continue thereafter. The same is true for vagal maneuvers which may transiently unmask the flutter waves (though more commonly will cause no changes)
Pitfalls of Diagnosing Atrial Flutter
— The rate isn’t always exactly 150. If the rate is slower (e.g. HR 125-140, it can resemble Sinus Tachycardia. Therefore, in any regular narrow-complex tachycardia with HR 130-170, it is important to consider atrial flutter. Also Atrial flutter patients are often stable, and therefore, there is time to work up the EKG
— If the rate is faster (e.g HR 160-175), it can resemble SVT as P waves become buried in the frequent QRS complexes. Of note, SVT typically presents with HR 170-250. You can attempt vagal maneuvers to either convert to NSR or cause unmasking of flutter waves. Adenosine can also unmask the underlying flutter.
Treatment of Atrial Flutter
— Treatment options to be discussed in more detail in a following conference. But briefly, the options include cardioversion, rate-control and +/- anticoagulation. Treatment is very similar to Atrial Fibrillation. Of note, atrial flutter is very sensitive to cardioversion often only requiring 50-100 J.
This week’s radiology review focused on Pelvic Ring Fractures. Again, it’s only a 5-minute review so we dedicated it to the AP view. However, in a detailed work-up, additional views (including inlet/outlet and CT) will be obtained.
Quick Review of AP Pelvic Xray
Classifying Pelvic Ring Fractures
— As is anything in Emergency Medicine, start with the basics. Is the pt hemodynamically stable or unstable? The pelvis is notorious for being able to hide blood. Also it is important to do a thorough secondary survey as these injuries are associated with high energy blunt trauma, and secondary injuries can be missed. For instance, pelvic ring fractures were associated with chest injury in 63% of cases, long bone fractures in 50% of cases, head and abdominal injury in 40% of cases, and spine fractures in 25% of cases (Orthobullets).
— Is the fracture stable vs. unstable? There are two classification systems that can be used (Tile Classification vs. Young-Burgess Classification) with the end goal of determining the stability and severity of the fracture. The Young-Burgess is used more commonly (reviewed below) and divides fractures by mechanism (Lateral Compression, Anteroposterior compression, and Vertical Shear)
- Lateral Compression Fracture (LC)
— Often seen in T-bone MVC or pedestrian hit from side
— Typically, Rami Fracture with ipsilateral iliac fracture.
— Most common Pelvic Ring Fracture.
- Anteroposterior Compression (APC)
— Often from head-on-collision MVC
— Symphysis widening. >2.5 cm is a more unstable fracture that often requires fixation surgery. May also have associated SI joint diastasis as well as disruption of SI ligaments
— These are the patients that present with hypotension. This is due to the mechanism that causes the iliac wings to be forced outward allowing for increased pelvic volume
- Vertical Shear
— Results from vertically oriented force. Most often fall from great height (e.g. fall from building onto legs)
Young Burgess Classification System
And as promised… For all the people that really want to get in the weeds, The Young Burgess Classification System. I love that vertical shear is not further divided by severity as it implies badness.
Fun Medical History
I really enjoy medical history, and it’s my goal to share at least a small piece of medical history at the end of each post. I actually learned this piece of trivia from Dr. Somy Thottathil. This past week we celebrated the 47th anniversary of the first CT scan ever. It took place on October 1, 1971, in Wimbledon, London. It was performed by the scientist Sir Godfrey Hounsfield (yep, of Hounsfield unit fame)–pictured below. It was only designed for brain imaging, and in this first Head CT, revealed a brain tumor in a 41-year-old female. In another 4 years, the first whole-body CT scanner was developed.
Additional fun fact–the development of this first CT scanner is partially owed to the Beatles. Hounsfield was part of the EMI company, which was the same company that owned The Beatles’ music. The profits from their music helped to fund this research.