UMEM Educational Pearls

Title: Early repolarization vs. STEMI

Category: Cardiology

Keywords: early repolarization, ST segment elevation, STEMI, ST elevation (PubMed Search)

Posted: 10/17/2010 by Amal Mattu, MD
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ECG early repolarization (or sometimes referred to as "benign early repolarization" or BER) is a common finding on ECGs, especially in young patients. It is a common "confounding" pattern when trying to identify STEMI. Here are some pearls that help in distinguishing BER vs. true STEMI. Remember at the outset, though, nothing in medicine is 100%....and that getting old ECGs or getting serial ECGs can be incredibly helpful.

1. BER is ONLY allowed to have STE that is concave upwards. If you ever see STE that is convex upwards (like a tombstone) or horizontal, it MUST be a STEMI.
2. BER should not have ST-segment depression, except maybe in aVR and V1. If there is ST depression in any of the other 10 leads, it is almost definitely a STEMI.
3. If you see STE in the inferior leads, compare the STE in lead II vs. lead III. If the STE in lead III is greater than the STE in lead II, it rules out BER....gotta be STEMI.
4. STE from BER is usually maximal in the mid precordial leads. You CAN have STE in the inferior leads with BER also, but you really shouldn't have STE isolated to the inferior leads. In other words, BER can have (1) STE in the precordial leads alone, or (2) STE in the precordial + inferior leads, but it should never have STE isolated to the inferior leads, and also the STE in the precordial leads should be more prominent than the STE in the inferior leads.
5. BER should usually not have STE > 5 mm. However, I've seen some occasional exceptions when the patient has large voltage QRS complexes.

 
Note that despite what I've said above, STEMI can occasionally produce STE in II > III (left circ lesion), STEMI often can give concave upward STE, and STEMI does not always produce reciprocal changes. So in other words, the rules above are  very good for ruling in STEMI (ruling out BER), but there are no good rules that rule out STEMI (or definitely ruling in BER). The rules above are pretty darn reliable, though nothing in medicine is 100%. But I'd say these are pretty close.
 
Once again, I'll emphasize that whenever there is even a trace of doubt, go the extra mile to get an old ECG for comparison, and/or get serial ECGs. It's much harder to defend a miss without those efforts.

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Title: Subungual Hematomas

Category: Orthopedics

Keywords: Subungual Hematomas (PubMed Search)

Posted: 10/16/2010 by Michael Bond, MD (Updated: 11/25/2024)
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Subungual Hematomas:

  • Subungual hematomas are collections of blood that form under the nail with injuries to the distal phalanx. 
  • Those that are < 25% of the nailbed can be drained via trephination and heal well.
  • Up to 94%  of subungual hematomas that are are associated with a distal phalanx fracture have a nailed laceration.  It is commonly taught this hematomas should have the nail removed and the nailbed repaired.  However  studies from the 1990's have shown that as long as the nail is attached to the nailbed or paronychia and is not displaced; trephination alone can be done to achieve similar outcomes.

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Title: Ondansetron and Oral Rehydration Therapy

Category: Pediatrics

Keywords: Ondansetron, Oral Rehydration, Therapy, vomiting, pediatrics (PubMed Search)

Posted: 10/15/2010 by Adam Friedlander, MD (Updated: 10/16/2010)
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You may already love ondansetron, but consider using it ORALLY followed by PO hydration in children with vomiting.

  • Improve ORT success
  • Decrease IV placements
  • Decrease admission rates
  • NOT cause any significant difference in the number of missed serious alternate diagnoses 

The size of the study that showed this: N of just under 35,000.

But don't skimp on dosing.  The dose is 0.1 - 0.15mg/kg, and you don't reach a max until 8mg.  To put this in perspective, a scrawny 115lb (about 53kg) middle school tennis player would get 8mg, an initial dose often reserved for chemo patients in the adult ED.

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Title: Intralipid for Drug Overdose

Category: Toxicology

Keywords: Intralipid, fat emulsion (PubMed Search)

Posted: 10/14/2010 by Bryan Hayes, PharmD (Updated: 11/25/2024)
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Emerging evidence supports using intravenous fat emulsion (Intralipid) therapy for various drug overdoses, particularly those that are lipophilic.  Within seconds to minutes of administration, toxic cardiovascular effects are reversed, including return of spontaneous circulation in cardiac arrest patients.  Central nervous system effects also tend to improve.

Lipophilic agents for which there has been success include:

  • Calcium channel blockers (verapamil, diltiazem, amlodipine)
  • Beta blockers
  • Bupropion
  • Quetiapine
  • Lamotrigine
  • Sertraline
  • TCA's
  • Diphenhydramine

Bottom line: Consider intralipid therapy early in the course of a hemodynamically unstable patient with suspected overdose.  Give a bolus of 1.5 mL/kg of 20% lipid emulsion over 1-2 minutes.



Title: Risk Factors for Post-stroke Complications

Category: Neurology

Keywords: stroke, cerebral edema, tPA, hemorrhage, NIHSS (PubMed Search)

Posted: 10/13/2010 by Aisha Liferidge, MD (Updated: 11/25/2024)
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  • When emergently managing stroke, be vigilant about anticipating potential complications and recognizing them with expediency, regardless of whether the patient receives tPA therapy.
  • The following are associated with greater risk of developing cerebral edema and/or post-tPA hemorrhage:

              ---  High NIH Stroke Scale scores.

              ---  Large areas of infarct.

              ---  Cerebellar infarcts.

              ---  Extended time to tPA administration.

              ---  Previous stroke.

              ---  Older age.
 

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Title: Heliox in severe asthma

Category: Critical Care

Keywords: asthma, heliox, airway (PubMed Search)

Posted: 10/12/2010 by Haney Mallemat, MD (Updated: 11/25/2024)
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Heliox is a mixture of oxygen and helium resulting in a gas less dense than air. In asthma, airway resistance causes turbulent airflow which increases the work of breathing. Heliox reduces airway resistance by increasing laminar airflow. 

 

Benefits: 

Better lung mechanics

Improved nebulizer delivery

Few known side-effects/complications

 

Drawbacks:

Expensive

Contraindicated in hypoxemic patients.

Paucity of large prospective randomized trials.

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Title: Documenting joint injury

Category: Orthopedics

Keywords: joint, documentation, physical examination (PubMed Search)

Posted: 10/9/2010 by Brian Corwell, MD (Updated: 11/25/2024)
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Previous pearls have described tips for smart and safe documentation of typical ED complaints such as chest pain.  Properly assessing and documenting orthopedic complaints is likewise very important.  No evaluation or chart is complete if it does not include include the following 7 components:

 

The joint above

The joint below

Motor

Sensory

Vascular

Skin

Compartments

The joint above/below is important in cases of shoulder and hip pain actually being radicular pain (from the neck and back respectively).  Also, hip pain from trauma may be due to a femur fracture for example.

For motor and sensory evaluation, test the most distal isolated innervation of a particular nerve (L5 - great toe dorsiflexion for example).

Note distal pulses and check ABIs for injuries with potential subtle vascular  findings.

Note intact skin especially in cases where the joint will be covered by a splint.

Note "soft" compartments especially in cases of forearm and lower leg fractures.

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Title: Endotracheal medication administration

Category: Critical Care

Keywords: endotracheal intubation, medication, acls, resuscitation (PubMed Search)

Posted: 10/7/2010 by Ellen Lemkin, MD, PharmD
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EMS in Maryland has REMOVED endotracheal medication administration from its ADULT protocols

This is due to:

  • Unclear efficacy and need for a much higher dosage
  • Ability to administer drugs via IO route
  • Decrease reliance on intubation
    • chest compressions only CPR
    • BiPAP use
  • Note this does not pertain to PEDIATRICS, where it is still included in its protocols


Title: Key Points for Evaluating Diplopia

Category: Neurology

Keywords: diplopia, cranial nerve palsy, monocular diplopia, binocular diplopia (PubMed Search)

Posted: 10/6/2010 by Aisha Liferidge, MD (Updated: 11/25/2024)
Click here to contact Aisha Liferidge, MD

  • Emergency department evaluation of diplopia is largely based on a comprehensive history and should always include the following questioning with documented findings:
  1. Does the diplopia resolve by covering one eye?  (Differentiates binocular diplopia (disappears when one eye covered; most common) from monocular diplopia (persists with one eye covered; usually related to a focal, ocular problem).
  2. Does the degree of diplopia change with direction of gaze and/or head position?  (Determines whether deficit related to cranial nerve innervation, helps localize associated paretic muscle).
  3. Is the diplopia horizontal (i.e. two objects side by side) or vertical (i.e. two objects one on top of the other)?  (Horizontal diplopia suggests cranial nerve III or VI deficit (i.e. lateral gaze function); vertical diplopia suggests cranial nerve IV deficit (i.e. elevator or depressor gaze function).
  4. Is there associated pain? (Suggests possible foreign body or extraocular muscle entrapment).
  5. Was there associated trauma? (Blow-out fractures can be associated with diplopia).
  6. Is there associated weakness, headache, confusion, or dizziness?  (Imaging usually indicated to rule out intracranial processes such as stroke or increased intracranial pressure).

    

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Respiratory Distress in the Ventilated ED Patient

  • In the ventilated patient with respiratory distress, evaluation of peak and plateau pressures can help to identify the cause.
  • Isolated increases in peak pressure suggest increased resistance to airflow and should prompt consideration of the following:
    • kinked or twisted ET tube
    • patient biting ET tube
    • obstructed ET tube
    • bronchospasm
    • lower airway obstruction
  • Increases in plateau pressure suggest decreased pulmonary compliance and should prompt consideration of the following:
    • unilateral intubation
    • pneumothorax
    • pulmonary edema
    • worsening pneumonia
    • abdominal HTN/compartment syndrome

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Chest pain is a very high risk chief complaint in emergency medicine. And although we are told by the experts what we should write on the chart, we often struggle with finding time to do so.

Given that we can't pick up every MI, dissection, and PE, what things can we document in the chart that prove we are thorough and that we have thought about a diagnosis? And how can we document a "protective thought process" without taking too much time to do so?

Consider documenting these on your chest pain charts:

  • Risk factors present/absent for ACS/MI, dissection, and PE
  • Good family history
  • Don't be sloppy with the history and physical exam. Doesn't matter if they help or not. Attorneys will have a field day discussing how sloppy the history and exam was. If the history and physical examination are bad get out the checkbook. 
  • Pulses in upper and lower extremity
  • Any leg swelling?
  • Any diastolic murmur?

Documenting key pertinent negative comments in the chart shows that you are thinking (and considering MI, Aortic Dissection, and PE), and whenever this can be shown in a chart, there is more ammunition for the defense attorney. 



Title: oxygen in acute MI

Category: Cardiology

Keywords: oxygen, acute myocardial infarction (PubMed Search)

Posted: 10/3/2010 by Amal Mattu, MD
Click here to contact Amal Mattu, MD

The traditional teaching has always been to use supplemental high-flow oxygen routinely for patients with acute MI. I recall specifically being taught in residency by EM, IM, and cardiology attendings that every acute MI patient should receive a minimum of 6 liters of supplemental oxygen via nasal canula, if not 100% oxygen, regardless of the initial pulse oximetry.

Mounting evidence, however, is demonstrating that the use of supplemental oxygen in patients that are "normoxic" (i.e. the production of "hyperoxia") is detrimental. Studies are demonstrating that there is no improvement in mortality or prevention of dysrhythmias; and in fact a trend towards increased mortality when patients are hyperoxic. This detrimental effect is likely the result of coronary vasoconstriction which occurs through several different mechanisms, all induced by hyperoxia. Oxygen, it turns out, is a vasoactive substance.

The takeaway point is very simple: if an AMI patient is not hypoxic, don't go overboard with the supplemental oxygen!

[Moradkhan R, Sinoway LI. Revisiting the role of oxygen therapy in cardiac patients. J Am Coll Cardiol 2010;56:1013-1016.]

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Patellofemoral Syndrome (Chondromalacia Patella)

  • Due to degeneration of the cartilage underneath the patella
  • Patients often present with:
    • A grinding sensation when the knee is extended
    • Pain in the front of the knee that typically worsens after sitting for a long period of time
    • Knee pain that worsens with using stairs, running or when needing to bend the knee deeply (i.e.: squats)
  • Commonly thought to be due to overuse (i.e.: new running program, or marching as in military recruits), but can also be due to anatomic abnormalities like pes planus or a large Q angle.  Ultimate cause is likely to be multifactorial
  • Can be treated with NSAIDs, and limiting activity
  • Physical Therapy that helps to strengthen the quadriceps can help prevent the patella from grinding on the femoral condyles.

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Title: Subtle SCFE

Category: Pediatrics

Keywords: SCFE, slipped capitofemoral epiphysis (PubMed Search)

Posted: 10/1/2010 by Adam Friedlander, MD
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Slipped capito-femoral epiphysis (SCFE) is a favorite board exam topic, and typically involves a young early or pre-adolescent obese girl with hip pain and the classic "ice cream falling off the cone" appearance on hip radiographs. However, keep these three pearls in mind when thinking about SCFE:

  1. Girls > Boys, but boys may be older at presentation - don't forget 15 year old boys and SCFE.
  2. An early radiographic finding may only be physis widening, so consider comparison films - the ice cream may only be levitating, but not falling off.
  3. 23% of these children present with knee pain - think before diagnosing an obese 15 year old boy with a knee sprain from football. *bonus* Recall that this injury is non weight-bearing.

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Title: Shellfish Poisoning

Category: Toxicology

Keywords: amnestic, neurotoxic, paralytic, shellfish (PubMed Search)

Posted: 9/30/2010 by Fermin Barrueto
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Although we may not be able to eat as much shellfish after the oil spill, there are still some left that can cause some interesting toxicity here in the USA. Shellfish act as vectors for the bacteria, virus etc that produces toxin thus not specific to one species of shellfish. There is a map attached that shows where shellfish poisoning occurs most. In the picture CFP=ciguatera, PSP=Paralytic and ASP=AmnesticC. Surprising the distribution and it will be interesting how the oil spill affects the distribution. Treatment for all of these is supportive with no known antidote and incidence increases during Red Tide months:

Tox Fish Map

  • Paralytic Shellfish Poisoning
    • Saxitoxin, potent, heat-stable, blocks fast sodium channels
    • Symptoms: Paresthesias, weakness, bulbar symptoms, blindness and paralysis (30m-2hrs after meal)
  • Amnestic Shellfish Poisoning (my favorite excuse for why I forget my anniversary)
    • Domoic acid build up created from Nitzchia spp (a marine diatom). This causes release of gluatamate thus causing excitotoxic nerve damage.
    • 1987 outbreak in Canada saw GI Sx in 24 hrs followed by HA, SZ, memory loss - has been fatal

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Title: Chlorhexidine usage for lumbar puncture

Category: Neurology

Keywords: chlorhexidine, arachnoiditis, lumbar puncture, neurotoxicity (PubMed Search)

Posted: 8/27/2010 by Dan Lemkin, MS, MD (Updated: 9/29/2010)
Click here to contact Dan Lemkin, MS, MD

Chlorhexidine (CHG) has rapidly become the antiseptic of choice for most skin preparation prior to any percutaneous procedures including:

  • venipuncture
  • laceration repair,
  • joint aspiration
  • lumbar puncture???

The Chlorprep(R) label notes: "DO NOT USE FOR LUMBAR PUNCTURE OR IN CONTACT WITH THE MENINGES" (attached)

Authors of the British Royal College of Anaesthetists 3rd National Audit Project provided some guidance for the use of chlorhexidine for spinal procedures

  • Clinicians must take care to prevent CHG from reaching the CSF
    • Keep CHG away from other drugs and equipment being used
    • Allow solution to dry prior to beginning procedure
    • Avoid using solutions > 0.5% chlorhexidine
  • Further comments
    • Chlorhexidine 0.5% in alcohol 70% is the optimal skin preparation for neuroaxial procedures
    • Risk of vertebral canal sepsis is greater than the very rare risk of neurotoxicity and arachnoidits from chlorhexidine
    • This is OFF-LABEL use and should be instituted formally at a departmental level with an audit process for complications

Further: Correspondance from the Journal of  Regional Anesthesia and Pain Medicine

"Dr. David Hepner published a correspondence in the April 2007 issue of Anesthesiology that stated the expert panel for Regional Anesthesia and Pain Medicine “felt strongly that although the US Food and Drug Administration has not approved chlorhexidine before lumbar puncture, it has a significant advantage over povidone iodine because of its onset, efficacy, and potency” and commented that “interestingly, povidone iodine is also not approved for lumbar puncture."

Chlorhexidine off-label use is supported in academic literature.  Due to specific labeling prohibiting use, a formal institutional policy to support such use may be indicated.

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Title: Continuing HAART for critically-ill HIV/AIDS patients?

Category: Critical Care

Keywords: HAART HIV AIDS Critical illness (PubMed Search)

Posted: 9/27/2010 by Haney Mallemat, MD (Updated: 9/28/2010)
Click here to contact Haney Mallemat, MD

While you should always involve ID consultants when managing critically-ill HIV/AIDS patients on HAART, consider this; sub-therapeutic levels of anti-retrovirals may promote HIV resistance, potentially invalidating a class of drug for future use. Therefore, it may be advantageous to discontinue the drug(s) during critical-illness to avoid resistance. 

 

Two examples leading to sub-therapeutic HAART levels in critical-illness:

  1. Reduced absorption of PO medications from bowel wall edema and/or decreased splanchnic perfusion.
  2. Interactions with HAART medications and the multitude of other drugs administered in the ICU.

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Title: posterior MI

Category: Cardiology

Keywords: electrocardiography, posterior, myocardial infarction (PubMed Search)

Posted: 9/26/2010 by Amal Mattu, MD (Updated: 10/3/2010)
Click here to contact Amal Mattu, MD

Approximately 4% of acute MIs will present as an isolated posterior MI (AKA "true posterior MI"). These are easily misdiagnosed as simply anterior ischemia because of the ECG findings. However, the distinction is critically important because posterior STEMI is now considered an indication for immediate reperfusion (PCI or lytics), whereas anterior ischemia is not.

The diagnosis of posterior STEMI is made by looking for:
1. ST segment depression, typically in leads V1-V3
2. upright T-waves in leads V1-V3
3. development of tall R-waves (R > S in amplitude) in V1-V3 over the course of a few hours (this is analogous to Q-waves forming in the posterior portion of the ventricle)

Early on, you may not be able to rely on the presence of tall R-waves to help you. Therefore, it's best to simply do the following: whenever you find ST-segment depression in leads V1-V3, always repeat the ECG using posterior leads (simply place a couple of the V leads on the left mid-back area). These leads will "look" directly at the posterior heart. If those leads show ST elevation, the diagnosis is posterior STEMI. If those leads don't show ST elevation, you can then make the diagnosis of simply anterior ischemia and hold off on immediate PCI or lytics.

The first ECG below shows ST depression in the anteroseptal leads, suspicious for posterior STEMI. The ECG was then repeated, second ECG, with leads V3-V6 placed wrapping around to the left mid-back area. The ST elevation in these leads confirmed the presence of a posterior STEMI and justified immediate reperfusion therapy.

 

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Title: Gamekeeper s/Skier s Thumb

Category: Orthopedics

Keywords: Thumb, Gamekeeper's thumb, Skier's thumb (PubMed Search)

Posted: 9/25/2010 by Brian Corwell, MD (Updated: 9/28/2010)
Click here to contact Brian Corwell, MD

Injury was originally described as an occupational hazard in Scottish gamekeepers (from breaking the necks of rabbits against the ground). Today, skiing is now the most common cause and injury is now the second most common orthopedic injury in skiers (MCL injury #1).

Injury to the ulnar collateral ligament (UCL) results from a sudden forced abduction (radial deviation) stress at the MCP joint of the thumb, commonly due to a fall against a ski pole or the ground.

http://blog.fitter1.com/wp-content/uploads/2010/04/b_14_1_2a.jpg

The most frequent site of rupture is the insertion into the proximal phalanx. The UCL may even avulse a small portion of the proximal phalanx at its insertion site.

http://img.medscape.com/pi/emed/ckb/sports_medicine/84611-97564-98460-1652013.jpg

Consider imaging before stress testing (to avoid further displacing a fracture)

http://img.medscape.com/pi/emed/ckb/sports_medicine/84611-97564-98460-1652060.jpg

Stabilize in a thumb spica splint and refer to hand surgery.

Calling this entity a “simple sprain” may result in chronic disability (chronic pain, instability, loss of pinch strength)

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Title: Quick Techniques for Assessing Ulnar, Median, and Radial Nerve Motor Function

Category: Neurology

Keywords: ulnar nerve, median nerve, radial nerve (PubMed Search)

Posted: 9/22/2010 by Aisha Liferidge, MD (Updated: 2/22/2011)
Click here to contact Aisha Liferidge, MD

  • When examining the hand, it is always important to document assessment of the ulnar, median, and radial nerves.
  • The motor function of the hand can quickly and simply be assessed with the following examination techniques:
  • Ulnar motor function >> Ask patient to first turn hand prone and spread fingers apart to a maximal distance.  Then, ask the patient to resist your attempts to squeeze the fingers together.
  • Median motor function >> Ask patient to touch the distal tip of the thumb to the distal tip of the fifth finger and hold it.  Then, attempt to pull the two fingers apart and ask patient to resist.
  • Radial motor function >> Ask patient to extend the wrist (i.e. as if trying to stop traffic) and push back against you attempting to push the hand into the flexed position.