UMEM Educational Pearls

Title: Synthetic Marijuana - What is it?

Category: Toxicology

Keywords: THC, marijuana (PubMed Search)

Posted: 2/18/2011 by Fermin Barrueto (Updated: 11/27/2024)
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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.

Attachments



Title: Tip for using ketamine in procedural sedation

Category: Neurology

Keywords: ketamine, conscious sedation, procedural sedation (PubMed Search)

Posted: 2/16/2011 by Aisha Liferidge, MD
Click here to contact Aisha Liferidge, MD

  • 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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Title: How good is the McConnell sign for diagnosing pulmonary embolism?

Category: Critical Care

Keywords: Pulmonary embolism, PE, echocardiography, ultrasound, hemodynamics, McConnell sign, right ventricle (PubMed Search)

Posted: 2/15/2011 by Haney Mallemat, MD (Updated: 11/27/2024)
Click here to contact Haney Mallemat, MD

 

  • McConnell sign is right ventricular (RV) free wall hypokinesis with normal apical contraction on echocardiography.
  • Finding McConnell sign has been associated with submassive and massive pulmonary embolism (PE) when moderate to high clinical suspicion exists. This is important if unstable patients are unable to tolerate other diagnostic studies.
  • After its description, the specificity of McConnell sign’s for PE has been questioned, as other pathologies can produce it (e.g., RV infarction and severe pulmonary HTN).
  • The paper referenced below retrospectively found that the sensitivity, specificity, positive predictive value, and negative predictive value of McConnell sign for diagnosing PE was 70, 33, 67, ad 36%, respectively.
  • Bottom line: The McConnell sign must be used with caution if used alone to diagnose PE; especially if thrombolytics are being considered.

 

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Title: Find the inconsistencies (UPDATED). Written by Dr. Michael Allison

Category: Trauma

Keywords: blunt trauma, pneumothorax, CXR supine, ultrasound, seashore, stratasphere (PubMed Search)

Posted: 2/14/2011 by Haney Mallemat, MD (Updated: 8/28/2014)
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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?

 

Show Answer

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Title: syncope and near-syncope

Category: Cardiology

Keywords: syncope, near-syncope, pre-syncope (PubMed Search)

Posted: 2/13/2011 by Amal Mattu, MD (Updated: 11/27/2024)
Click here to contact Amal Mattu, MD

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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Title: To CT or not to CT, Part II

Category: Pediatrics

Keywords: head CT, trauma, pediatrics, head injury (PubMed Search)

Posted: 2/11/2011 by Adam Friedlander, MD (Updated: 11/27/2024)
Click here to contact Adam Friedlander, MD

 

Head injuries in children over 2yo are stress provoking as well.  Here are the rules for that age group, piggy-backing on last week's pearl, based on a large (42,412 children, 31,694 >2yo) multi-center trial conducted by PECARN.
 
In children >2yo, if all of the following criteria are met, there is 99.95% chance that no clinically important traumatic brain injury exists (defined as an injury requiring intervention):
  • normal mental status
  • no loss of consciousness 
  • no vomiting
  • non-severe injury mechanism
  • no signs of basilar skull fracture
  • no severe headache
No children in either low risk group required neurosurgical intervention.
 

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Title: Historical Figures in Toxicology: Paracelcus

Category: Toxicology

Keywords: dose-response, paracelsus (PubMed Search)

Posted: 1/26/2011 by Bryan Hayes, PharmD (Updated: 2/10/2011)
Click here to contact Bryan Hayes, PharmD

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).



Title: Who is Eligible for IV tPA at up to 4.5 Hours?

Category: Neurology

Keywords: IV tPA, stroke, alteplase (PubMed Search)

Posted: 2/9/2011 by Aisha Liferidge, MD (Updated: 11/27/2024)
Click here to contact Aisha Liferidge, MD

  • 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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Title: Resource for Teaching in the ED

Category: Airway Management

Keywords: teaching, NEJM, app (PubMed Search)

Posted: 2/7/2011 by Rob Rogers, MD (Updated: 11/27/2024)
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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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Title: hyperkalemia, digoxin, and calcium

Category: Cardiology

Keywords: hyperkalemia, digoxin, calcium (PubMed Search)

Posted: 2/6/2011 by Amal Mattu, MD (Updated: 11/27/2024)
Click here to contact Amal Mattu, MD

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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Title: Immediate Hypersensitivity Reactions (IHR) to Radio Contrast Media (RCM)

Category: Pharmacology & Therapeutics

Keywords: iohexol, iodixanol, radio contrast media, immediate hypersensitivity reactions (PubMed Search)

Posted: 2/5/2011 by Bryan Hayes, PharmD
Click here to contact Bryan Hayes, PharmD

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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Title: To CT or not to CT, Part I

Category: Pediatrics

Keywords: head CT, trauma, pediatrics, head injury (PubMed Search)

Posted: 2/4/2011 by Adam Friedlander, MD
Click here to contact Adam Friedlander, MD

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.

 
In children <2yo, if the following criteria are met, there is a near 0% (95% CI) chance of a clinically important traumatic brain injury (defined as an injury requiring intervention):
  • normal mental status
  • no non-frontal scalp hematoma
  • no loss of consciousness, or LOC <5s
  • non-severe injury mechanism
  • no palpable skull fracture
  • acting normally according to the parents
Approximately 25% of the patients who had CTs, fit the low risk criteria above, and none had clinically significant brain injuries.  
 
In other words, just follow these simple rules to cut down the number of head CTs done on children <2yo by 25%.

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Title: Methemoglobinemia

Category: Toxicology

Keywords: Methemoglobinemia,methylene blue (PubMed Search)

Posted: 2/3/2011 by Ellen Lemkin, MD, PharmD (Updated: 11/27/2024)
Click here to contact Ellen Lemkin, MD, PharmD

 

Suspect methemoglobinemia if you have a patient with persistent cyanosis, tachypnea, low pulse oximetry, and a lack of response to 100% oxygen therapy, or an elevated PaO2 on ABG and a low O2 sat on pulse ox.
 
Methemoglobin results from exposure to chemicals that oxidize the ferrous iron in hemoglobin to the ferric state, resulting in a functional anemia.  Usually a low level is reduced back to hemoglobin by cytochrome b5, NAD, G6PD, and glutathione reduction enzyme systems.  
 
Diagnose by confirmed by a methemoglobin level, although the most convenient and rapid test of choice is multiple wave co-oximetry. (not the standard 2 wave pulse ox).
 
Treat if they are symptomatic; use methylene blue, 1 mg/kg slow push. Patients should improve in one hour. Use with extreme caution in patients with G6PD disease (if at all).
 


Title: Recognizing True Stroke Versus Seizure

Category: Neurology

Keywords: stroke, seizure (PubMed Search)

Posted: 2/3/2011 by Aisha Liferidge, MD (Updated: 11/27/2024)
Click here to contact Aisha Liferidge, MD

  • Seizure is very rarely associated with true ischemic stroke; the presence of seizure is, in fact, a  contraindication for administering t-PA in patients thought to have had a stroke.

 

  • Thus, when patients present with an alleged stroke in the setting of seizure, be skeptical as to whether there truly was an ischemic stroke and do more investigating to ascertain a satisfactory conclusion.  In these cases, perhaps the patient suffered a hemorrhagic stroke, which is associated with seizure more often than is ischemic stroke.

 

  • Post-seizure sequelae can present as focal neurologic deficit that mimics stroke (i.e. Todd's Paralysis), but note that these are generally associated with partial, not generalized, seizures.

  

  • Finally, remember that patients who have had strokes in the past are at increased risk for having future strokes AND for developing a seizure disorder secondary to the focal area of brain tissue damaged by their prior stroke.  These patients, therefore, may present with a combination of true, new OR exacerbated, old stroke symptoms, with or without seizure.


Title: Critical illness and hemoglobin concentration

Category: Critical Care

Keywords: hemoglobin, anemia, transfusions, hemorrhage, conservative, liberal, hemorrhaging (PubMed Search)

Posted: 2/1/2011 by Haney Mallemat, MD
Click here to contact Haney Mallemat, MD

The optimal hemoglobin concentration during critical illness is unknown. Although a liberal transfusion strategy (Hb 10-12 g/dL) was once believed to be beneficial for hemodynamics, evidence suggests targeting a conservative strategy (Hb 7-9 g/dL) does not increase mortality, while the unnecessary transfusion of blood products can cause harm (transfusion associated lung injury, infection, etc.) in the non-hemorrhaging patient. 

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Title: What's wrong with this picture? By John Greenwood, MD

Category: Trauma

Keywords: Apical cap, dissection, blunt aortic injury, chest xray, radiology (PubMed Search)

Posted: 1/31/2011 by Haney Mallemat, MD
Click here to contact Haney Mallemat, MD

Question

44 y/o female restrained driver s/p motor vehicle crash complaining of chest pain and shortness of breath. 

Show Answer

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Title: Dabigatran (Pradaxa) concerns

Category: Toxicology

Keywords: Dabigatran, anti-coagulation, toxicology, coumadin (PubMed Search)

Posted: 1/27/2011 by Fermin Barrueto
Click here to contact Fermin Barrueto

 

Dabigatran (Pradaxa), an antithrombin medication, was discussed in an earlier pearl and thought I would play devil's advocate and explain the possible concerns:

  • Yes you don't need INRs to evaluate therapeutic levels but the problem is also don't know if its subtherapeutic or supratherapeutic. This can be an issue during times of transition fromLWMH or coumadin. There are specific protocols to follow for "bridging".
  • Though not clinically significant, there was an increase in myocardial infarction in thedabigatran (Pradaxa) group when compared to coumadin - remember vioxx?
  • FDA approved dabigatran for stroke prevention, embolism, in AF patients. Though people will automatically translate all of the indications coumadin has that cannot be done yet.
  • No reversal agent so in an acute (ED) setting, you are in trouble and are depending on the relatively short half-life to get you out of trouble.

Toxicology Mantra: You never want to be the first person or the last person to use a drug



 

  • The risk of ischemic stroke or intracerebral hemorrhage (ICH) during pregnancy and the first 6 weeks postpartum is 2.4 times greater than for non-pregnant women of similar age and race. 
  • The risk of ischemic stroke during pregnancy is not increased during pregnancy, per se, but is increased 8.7 fold during the 6 weeks postpartum. 
  • ICH showed a small relative risk (RR) of 2.5 during pregnancy, but increased dramatically to a RR of 28.3 in the 6 weeks post partum.
  • Take Home Point:  Your suspicion for true stroke should heighten in pregnant and post-partum patients, particularly for ICH and ischemic stroke during the the first 6 weeks after delivery.

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Valproic Acid in Status Epilepticus

  • In previous pearls, we have discussed the treatment of status epilepticus (SE) with first-line (benzodiazepines) and second-line agents (phenytoin/fosphenytoin).
  • Refractory SE is defined as the failure to respond to both first- or second-line antiepileptic medications.
  • Valproic acid is listed in many algorithms as a third-line agent for treating SE.
  • Avoid valproic acid in refractory SE patients who have hepatic disease or dysfunction.
  • Although rare, valproic acid can cause a fatal hepatotoxicity in these patients. 

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