UMEM Educational Pearls

Continuing with the synthetic/designer drug theme. Last time we were discussing synthetic marijuana.  Another old drug making a resurgence under the designer drug category is mephedrone.This amphetamine-like drug has been purportedly the active substance in "bath salts". It has also been sold as "plant food" - still trying to figure that one out.

Sold in head shops under the name Bliss or Cloud 9 - they have been reported to be available in Baltimore, MD recently. They can also be bought over the internet. Crushed, snorted or ingested, the effect is similiar to cocaine with a largely sympathomimetic toxidrome. Mephedrone has been labeled an entactogen with users behaving similiar to an MDMA ingestion. A Baltimore news station incorrectly called it "synthetic cocaine" - though the effect may be similiar, completely different molecular structure.

Treatment is cooling, check lytes (especially sodium), check for rhabdomyolysis and sedation with benzodiazepines. Below is one link from a Denver News Station. Attached is a picture of a bath salt product.

The latest and greatest on the street - synthetic marijuana and bath salts!

http://www.thedenverchannel.com/news/26567376/detail.html

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• 1102241706_bath-salts.jpg (38 Kb)

• A simple febrile seizure (SFS) is generalized, tonic-clonic in type, and occurs in children between the ages of 6 months and 6 years of age, lasting less than 15 minutes and NON-recurring in a 24 hour period.
• According to the 1996 guidelines of the American Academy of Pediatrics (AAP) and based on the consensus that seizure is a common presenting symptom of bacterial meningitis, the following indications should be used to determine whether lumbar puncture (LP) is performed in patients presenting with SFS:

             --  6 to 12 months  >  "strongly consider" LP

              --  12 to 18 months  >  "consider" LP

              --  18 months and up  >  LP not routinely necessary; may consider after clinical assessment

              --   Any infant/child with recent antibiotic treatment plus SFS  >  "strongly consider" LP

• Despite these relatively outdated guidelines based largely on retrospective data, more recent literature suggests that serious bacterial infections such as meningitis are very rarely associated with simple febrile seizures, such that guidelines and practice paradigms may soon change.   

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Hemodynamic Monitoring in the Ventilated Patient

• Consider pulse pressure variation (PPV) as a method to monitor volume responsiveness in your mechanically ventilated ED patients.
• The theory behind PPV:
  • When a positive pressure breath is delivered via the ventilator, pleural pressure rises and causes a decrease in venous return, right heart filling, and right heart output.
  • Simultaneously, the positive pressure breath causes an increase in left heart filling and a decrease in left heart afterload.  This is reflected clinically as an increase in blood pressure.
  • Within a few beats, the decreased right heart output is transmitted to the left heart resulting in a decrease in blood pressure during expiration.
• Patients who are volume depleted can have significant differences in blood pressure between inspiration and expiration - i.e. a large variation in pulse pressure.
• PPV values > 12% have been shown to identify patients who are volume responsive.
• Importantly, PPV works best in vented patients who have no spontaneous respiratory effort, are in sinus rhythm, and receiving 8 ml/kg tidal volumes.

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[Here's a nice simple pearl from Jeff Tabas, MD (Prof of EM at UCSF).]

3 causes of bradycardia to consider when the rhythm is not clearly sinus bradycardia:
1. Junctional bradycardia
2. Hyperkalemia
3. Digoxin toxicity

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Distal Radius Fractures

Typically distal radius fractures are treated with closed reduction and splinting in the ED, followed by operative repair. This is done because it is felt that patients will have the best functional outcomes if the bones are restored to their normal anatomic alignment.  However, two studies published in 2010 suggest differently.

The study by Neidenbach showed that after one year there was no difference in functional outcomes between patients that were just splinted in the ED in the position the fracture was found versus those that had closed reduction with splinting. 

The second study by Ego showed that there was no difference in outcomes between those that underwent conservative treatment with closed reduction and splinting versus those that underwent operative repair.

The take home point from these studies for the EM physician is that most distal radius fractures can be splinted in the position found with them following up with an orthopaedist.  There is probably little advantage to performing a closed reduction in the ED knowing that this procedure can use a lot of valuable time and resources.

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Sold under the name of K2, Spice. Patients exposed to this will present with dry mouth, paranoia, tachycardia, hallucinations but will resolved rather quickly over several hours. Observation in the ED and supportive care is usually all that is needed. A little history about synthetic marijuana:

• JWH-018 is a synthetic cannabinoid (SC) that acts at cannabinoid receptors.
• Synthetic cannabinoids were created s in the 1960’s and continued to be developed as appetite stimulants (e.g., dronabinol).
• The JWH series of SCs are named for the chemist who first synthesized them, John W. Huffman, Ph.D. (thus the JWH prefix).
• SCs recently appeared for sale in smoke shops and other outlets (such as gas stations) as herbal incense.
• These products contain plant material that mimics smell and appearance of marijuana but is adulterated with one or more SCs.

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• 1102180659_Spice_drug.jpg (558 Kb)

• Procedural sedation consists of administering sedatives (i.e. midazolam, etomidate, propofol) or dissociative agents (i.e. ketamine) with or without opioid analgesics such as morphine and fentanyl.
• The widespread use of ketamine for procedural sedation may be limited by physician concern about unpleasant, vivid dreaming, hallucinations, and reactions after its administration known as recovery agitation.  This has been found to occur in 12 percent of cases and is seen less often in youth.
• In some instances, ketamine might be considered more ideal than other procedural sedation agents because it provides sedation, analgesia, and an amnestic-like dissociation between mind and body.
• Recent studies have shown that administering ketamine with a benzodiazepine such as midazolam significantly reduces the incidence of recovery agitation following procedural sedation; this alternative might therefore be considered when appropriate.
   

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Question

(Please note the prior version of this pearl was incorrect with respect to the images referenced. This version is corrected.)

Patient s/p blunt chest trauma. CXR (image 1) vs. lung ultrasound (image 2), do you see any inconsistencies?

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Is there a difference in the workup, etiologies, or prognosis between patients with syncope vs. near-syncope? Traditional teaching indicates that there is no difference, but that doesn't necessarily reflect common practice. Physicians sometimes are a bit less concerned about patients with near-syncope vs. patients with true, full-blown syncope; and many syncope studies exclude patients with near-syncope.

Grossman and colleagues recently published a useful reminder that patients with syncope and near-syncope have a similar 30-day rate of adverse outcome. However, they have a lower admission rate, reflecting the lower level of concern physicians have in their evaluation. Be wary of those patients with near-syncope. Don't be reassured just because they didn't hit the floor...yet!


 

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Many consider Paracelsus (1493–1541) as the father of modern toxicology.

• He was the first to emphasize the chemical nature of toxic agents.
• He stressed the need for proper observation and experimentation regarding the true response to chemicals.
• He underscored the need to differentiate between the therapeutic and toxic properties of chemicals when he stated in his Third Defense, "What is there that is not poison? All things are poison and nothing [is] without poison. Solely, the dose determines that a thing is not a poison."

The introduction of the dose–response concept might have been his most important contribution to toxicology, meaning that everything is toxic at the right dose (even oxygen and water).

• The benefit of IV alteplase (tPA) beyond the conventional window of 3 hours after onset of stroke symptoms was established by the randomized ECASS III Trial, which compared treating acute ischemic stroke with IV alteplase versus placebo, between 3 and 4.5 hours (median 4 hours).
• The study found a significantly more favorable outcome amongst participants who received alteplase (odds ratio 1.34, 95% CI 1.02 - 1.76).  The overall number needed to treat was 14.
• The standard exclusion criteria used in this study differed from those of others, and these characteristics must be taken into account when deciding which patients are eligible for treatment at up to 4.5 hours.
• Therefore, data from ECASS III can not be used to support treating at up to 4.5 hours in the following types of patients:

              -- Age > 80 years old

              -- NIH Stroke Scale > 25

              -- History of combination of previous stroke and diabetes

              -- On anticoagulation medication, regardless of INR

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Acute LV Dysfunction in the Critically Ill

• Approximately one-third of critically ill hospitalized patients develop acute LV dysfunction, most often due to a stress-induced cardiomyopathy.
• In these patients, up to 25% develop an acute dynamic LV outflow tract obstruction.
• Consider acute LV outflow tract obstruction in hypotensive patients with a new systolic ejection murmur in the left parasternal area.
• Aggressive IVFs is central to the management of these patients with LV outflow tract obstruction.

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Great resource for teaching in the emergency department....

Here is a great new app that you can use when teaching residents and students in the ED. It's the NEJM app. Great pics, videos, audio, procedures, and articles. And, it's FREE.

Just go to the App store and search "NEJM"

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For those that listen to EmedHome's EM Cast, you may have already heard this but I thought it's worth sharing with everyone else:

Many of us learned in our training that you should never give calcium to a hyperkalemic patient that is on digoxin or has digoxin toxicity. However, there's a paucity of data to support this contention. Here's one more article suggesting that calcium in the presence of digoxin or dig-toxicity may, in fact, be okay.

Levine and colleagues retrospectively evaluated 161 patients with digoxin toxicity, of whom 23 patients received calcium for hyperkalemia. None of the patients developed significant dysrhythmias in the first hour after calcium, and there was no increase in mortality rate.

Though not definitive, this is further support for treating hyperkalemia with calcium even in the presence of digoxin toxicity.

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Many patients report an allergy to iodinated RCM, sometimes adding to the complexity of diagnostic decision making.  Here are a few pearls to help:

• Seafood or shellfish allergy is NOT a risk factor for IHR to RCM
• Iodine and iodide are small molecules that do NOT cause anaphylactic or anaphylactoid reactions
• Life-threatening reactions occur in only 0.004 to 0.04 percent of nonionic low osmolality RCM infusions
  • Our radiology department uses primarily iohexol (Omnipaque) for IV contrast with a low osmolality of 844
  • Iodixanol (Visipaque) is the iso-osmotic alternative with an osmolality of 290

Bottom line: Despite the lack of cross reactivity with shellfish/iodine allergies AND the very low risk associated with today’s low osmolality agents, premedication is still indicated in patient’s with a history of IHR to RCM.

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Head injuries in children under 2yo are stress provoking, particularly with regard to when you should be getting a head CT.  Luckily, a large (42,412 children, 10,718 <2yo) multi-center trial exists to guide your behavior.

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