Journal Feed Weekly Wrap-Up

We always work hard, but we may not have time to read through a bunch of journals. It’s time to learn smarter. 
Originally published at JournalFeed, a site that provides daily or weekly literature updates. 
Follow Dr. Clay Smith at @spoonfedEM, and sign up for email updates here.

#1: Giant Cell Arteritis – Accuracy of H&P and Labs

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No single clinical or laboratory feature is enough to rule in or out giant cell arteritis (GCA, aka temporal arteritis). Vascular imaging or temporal artery biopsy is warranted. In the ED, we may need to start treatment prior to a definitive diagnosis being made.

Why does this matter?
GCA is a medium to large vessel vasculitis. Notably, it can inflame the temporal arteries and may lead to blindness if untreated. It is treated with a prolonged course of high dose glucocorticoids, which are not without side effects. It is diagnosed with history, exam, labs, imaging, and temporal artery biopsy (TAB). In the ED, we usually do the first three: history, exam, and labs. How good are these in diagnosing GCA?

This gives me a headache…
This article is a regular feature in ACEM, a concise review of previously published evidence with EM-relevance. In this case, it summarizes this systematic review. This included 68 studies, >14,000 patients. Included studies were heterogeneous, and none were performed in an ED setting. The gold standard also varied: TAB confirmation in 38 studies; clinical diagnosis in the rest. Keep in mind, TAB is not an ideal gold standard in itself and may have false negatives.

The strongest positive predictors (positive likelihood ratios) were:

  • Limb claudication: 6.0

  • Jaw claudication: 4.9

  • Temporal artery thickening: 4.7

  • Temporal artery loss of pulse: 3.3

  • Platelet count > 400 x 1000/μL: 3.8

  • Temporal tenderness: 3.1

  • ESR > 100 mm/h: 3.1

The strongest negative predictors (negative likelihood ratios) were:

  • ESR < 40 mm/h: 0.18

  • C reactive protein < 2.5 mg/dL: 0.38

  • Age < 70 years: 0.48

There is no single clinical or laboratory variable that clinches or rules out the diagnosis of GCA. Each variable (or combinations of variables) increases or decreases suspicion for GCA. Confirmation requires either vascular imaging (CT/MRI) or TAB. But even these advanced tests are imperfect. POCUS is an emerging new tool as well, as we will learn tomorrow. My advice in the ED is to consider GCA in patients with any of the above positive symptoms, ensure solid and prompt follow up, and start treatment.

Diagnostic Accuracy of the History, Physical Examination, and Laboratory Testing for Giant Cell Arteritis. Acad Emerg Med. 2020 Dec 20. doi: 10.1111/acem.14196. Online ahead of print.

 #2: 5th MT Avulsion Fracture – Shoe or Cast?

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In patients with 5th metatarsal base avulsion fractures, pain at 6 months after treatment with a hard-soled shoe and weight bearing as tolerated was non-inferior to a short-leg cast. Patients treated with hard-soled shoe also had reduced time to return to pre-injury activity.

Why does this matter?
The 5th metatarsal base avulsion fracture is a common foot injury. Optimizing treatment for these common injuries should be patient and outcome centered. If we can increase function while injured, and reduce time to recovery, that would be an optimal treatment plan.

These hard-soled shoes were made for walkin’…
78 patients (aged 18-65) with 5th metatarsal zone 1 tuberosity avulsion, comminuted, or displaced fractures were placed in a short leg posterior splint after initial ED or outpatient clinic visit. At a 1-week follow up appointment, participants were prospectively randomized to either treatment with a hard-soled shoe or short leg cast, with both groups having weight bearing as tolerated restriction. Primary outcome was mean difference in the 100-mm Visual Analogue Score (a validated pain score) at 6 months after the fracture. The absolute difference comparing the hard-soled shoe group to the short leg cast was -1.3 mm (95% CI -4.3 to 1.8mm, 8.6 ± 7.0 mm vs 9.8 ± 7.3 mm). A secondary outcome, return to pre-injury activity (days), was significantly reduced in the hard-soled shoe group (37.2 ± 14.4 vs 43.0 ± 11.1, p = 0.04). Patient satisfaction was similar between groups.

While several key types of patients were excluded (i.e. obesity, diabetes, concurrent lower-extremity injury, open or pathologic fractures), this opens the door for future studies for possible immediate treatment with hard-soled shoe. This would be faster for providers and, most importantly, seems to be more patient centered. Our orthopedic group recommends immediate use of a walking boot for these fractures, which is nice.

Hard-Soled Shoe Versus Short Leg Cast for a Fifth Metatarsal Base Avulsion Fracture: A Multicenter, Noninferiority, Randomized Controlled Trial. J Bone Joint Surg Am. 2020 Dec 2. doi: 10.2106/JBJS.20.00777. Online ahead of print.

Minor point: I sent this to my sports medicine wife who pointed out that a 5th MT avulsion fracture at the base is different than a Dancer’s fracture: “A true dancer’s fracture occurs mostly in the middle portion of the long metatarsal bone and is oriented diagonally along the shaft. The fracture line may even spiral and rotate throughout the bone.”

I should have just stuck with the description and not used a nickname. I was always taught that a zone 1, 5th MT base avulsion fracture was called a dancer’s fracture, and a zone 2 was a Jones fracture. Now I see that the nomenclature varies. Radiopaedia calls it a dancer fracture or pseudo-Jones. Several other sites call the avulsion a pseudo-Jones. And I see many sources that indicate a “dancer’s fracture” involves the diaphysis, often in a spiral-type injury. So, I will amend the post and remove “dancer.” I will also remove any reference to Dasher, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, or Rudolph. It is too confusing to use a nickname. Thanks for clarifying!

Spoon Feed
IV diltiazem and IV metoprolol are two of the most common drugs used to treat hemodynamically stable atrial fibrillation with rapid ventricular response (RVR).  Diltiazem achieved rate control more quickly than metoprolol (15 min vs. 30 min); however, there was no statistically significant difference between sustained rate control at 3 hours.

Why does this matter?
Atrial fibrillation is the most common sustained cardiac arrhythmia encountered in the ED.  Timely and adequate treatment of the arrhythmia is important for patient care and disposition.

These drugs are trendy AF…
Data were gathered retrospectively by review of the electronic medical record.  573 patients were initially identified; however, only 51 patients were included, which means this was a very small study.  Important exclusion criteria were initial HR>220bpm, SBP<90mmHg, receipt of both medications to achieve initial rate control, acute decompensated heart failure and, interestingly, lack of rate control at 30 minutes.  The primary outcome of this study was sustained rate control, HR <100 bpm, for 3 hours from the time initial rate control – this was not statistically significant between the two groups: diltiazem 87.5% vs. metoprolol 78.9%, p = 0.45. As previously mentioned, subjects were excluded from this study if rate control was not achieved by 30 minutes.  Diltiazem achieved initial rate control in about half the time it took metoprolol to achieve adequate rate control. However, this may have been confounded by the medication doses.  Patients given diltiazem received a median dose of 0.24mg/kg (usual dose 0.25mg/kg) and only 6.3% of patients required a second dose.  In contrast, patients receiving metoprolol received a median dose of 0.05mg/kg (usual dose 0.15mg/kg), and 42.1% of patients required repeat dosing.  More patients in the diltiazem group had new-onset atrial fibrillation, whereas those in the metoprolol group tended to be on a beta-blocker at home, suggesting chronic atrial fibrillation.  After initial rate control with IV medications, 75% of patients in the diltiazem group received PO medications (median administration time 168 minutes) and 68% in the metoprolol group received PO medications (median time to administration 80 minutes).  Perhaps if we got PO medications on board more quickly, the rate of sustained rate control would increase. Notably, safety outcomes between the two groups were not significantly different.

Comparison of sustained rate control in atrial fibrillation with rapid ventricular rate: Metoprolol vs. Diltiazem. Am J Emerg Med. 2020 Dec 3;40:15-19. doi: 10.1016/j.ajem.2020.11.073. Online ahead of print.

#4: More Evidence – Diltiazem vs Metoprolol A-fib with RVR

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There was no difference in rate control (<110 beats per minute at 2 hours) for patients with atrial fibrillation with rapid ventricular response between IV diltiazem or metoprolol.

Why does this matter?
Yesterday, we learned there was little difference in the two drugs in a small retrospective study. The AHA doesn’t recommend one agent over another for atrial fibrillation with rapid ventricular response (a-fib, RVR). Pharmacokinetically, diltiazem may work faster and have a shorter duration of action than metoprolol. So, which agent should you choose? What does this larger cohort show?

Race for rate control
This was a single center retrospective study of patients with a-fib with RVR, comparing 166 who received metoprolol and 183 who received diltiazem. For rate control 2 hours after the last bolus, there was no statistical difference: 45.8% metoprolol vs 42.6% diltiazem, p = 0.590. There was a statistically but not clinically meaningful reduction in heart rate at 30 minutes, by 6 beats per minute, favoring diltiazem. Bradycardic events were statistically the same. The rate of diastolic hypotension <60 was higher in the diltiazem cohort, but systolic hypotension was statistically the same. In short, this is low quality evidence that these agents are almost the same for rate control in patients with a-fib with RVR. In my practice, if a patient is already taking a beta-blocker chronically, I will not add on an IV non-dihydropyridine calcium channel blocker (CCB) and vice versa. Why not mix beta-blockers and CCBs? Anecdotally, I have seen profound bradycardia in such cases if patients happen to spontaneously convert to normal sinus rhythm. Take this advice for what it’s worth, which is probably not much.

Evaluation of metoprolol versus diltiazem for rate control of atrial fibrillation in the emergency department. Am J Emerg Med. 2020 Nov 22;S0735-6757(20)31063-9. doi: 10.1016/j.ajem.2020.11.039. Online ahead of print.

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