Contributor: Travis Barlock, MD

Educational Pearls:

Endocannabinoid System: THC binds CB1 and CB2 receptors in neurons and immune cells

• Δ9-Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis

• CB1 and CB2 receptors typically bind endogenously-produced 2-arachidonoylglycerol (2-AG) and anandamide (AEA) to regulate pain, stress, and inflammation

• THC similarly binds CB1 and CB2, leading to the cannabinoid high: euphoria, paranoia, anxiety, analgesia, anti-inflammation, and appetite, among a variety of others

• Ingestion via edibles, vice inhalation via smoking, leads to chemical modification of Δ9-THC to 11-hydroxy-Δ9-THC, which more easily crosses the blood-brain barrier and binds CB1 with higher affinity, leading to increased psychoactivity

Cannabinoid Hyperemesis Syndrome (CHS): Chronic THC use leading to the classic presentation of persistent nausea and intense, frequent vomiting

• Chronic activation of CB1 receptors in brain builds a tolerance and dependence on THC, in addition to chronic activation of the capsaicin and vanilloid receptor TRPV1, which binds capsaicin or is activated by heat

• Treatment by warm showers works due to TRPV1 activation by heat

• Treated with benzodiazepines, fluids, and gastro-intestinal or central nervous system agents according to patient presentation

Over 200 synthetic cannabinoids have been created (K2, spice, black mamba, mojo, etc), which are more dangerous and can lead to a variety of etiologies

Acetaminophen binds CB1 receptors to reduce inflammatory pain

References

1. Loganathan P, Gajendran M, Goyal H. A Comprehensive Review and Update on Cannabis Hyperemesis Syndrome. Pharmaceuticals (Basel). 2024;17(11):1549. Published 2024 Nov 18. doi:10.3390/ph17111549

2. Wall ME, Sadler BM, Brine D, Taylor H, Perez-Reyes M. Metabolism, disposition, and kinetics of delta-9-tetrahydrocannabinol in men and women. Clin Pharmacol Ther. 1983 Sep;34(3):352-63. doi: 10.1038/clpt.1983.179. PMID: 6309462.

3. Mills B, Yepes A, Nugent K. Synthetic Cannabinoids. Am J Med Sci. 2015 Jul;350(1):59-62. doi: 10.1097/MAJ.0000000000000466. PMID: 26132518.

4. Klinger-Gratz PP, Ralvenius WT, Neumann E, et al. Acetaminophen Relieves Inflammatory Pain through CB1 Cannabinoid Receptors in the Rostral Ventromedial Medulla. J Neurosci. 2018;38(2):322-334. doi:10.1523/JNEUROSCI.1945-17.2017

Summarized by Sam Pahl | Edited by Sam Pahl & Ahmed Abdel-Hafiz, NREMT-P

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Contributor: Aaron Lessen, MD

Educational Pearls:

• There has long been many questions about which IV fluid is best for ED resuscitation

• Multiple adult studies have shown no clear benefit of balanced fluid vs normal saline

• A large pediatric randomized clinical trial published in April compared balanced fluid vs normal saline in children with septic shock

• • The study included about 9,000 patients from 47 emergency departments in five countries

  • Patients with septic shock were randomized to receive either balanced fluid or normal saline

  • The primary outcome was adverse kidney event (death, dialysis, or persistent kidney dysfunction) at 30 days or hospital discharge

  • Results showed no difference in any safety outcomes and no adverse events occurred

• The key takeaway is that early fluid resuscitation matters more than which crystalloid you choose

References

1. Balamuth F, Weiss SL, Long E, et al. Balanced Fluid or 0.9% Saline in Children Treated for Septic Shock. New England Journal of Medicine. Published online April 23, 2026. doi:https://doi.org/10.1056/nejmoa2601969

Summarized by Meg Joyce, MS3 | Edited by Meg Joyce & Ahmed Abdel-Hafiz, NREMT-P

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Carepoint Journal Club is a quarterly series with discussions about a medical topic, brought to you by Carepoint's Emergency Physicians.

Contributor: Taylor Lynch, MD

Educational Pearls:

Conduction abnormalities are a common and clinically significant complication in patients who undergo transcatheter aortic valve replacement (TAVR)

Clinical Features

• The most common abnormalities include high grade AV block and new onset LBBB

• • Due to the close proximity of the aortic annulus to the AV node and His-Purkinje system

  • More common in males, the elderly, and those with pre-existing conduction disease (RBBB or LBBB)

• Sinus pauses and sinus arrest are a rare post-TAVR rhythm disturbances

• • Temporary failure of sinus node firing with absent P waves, followed by return of sinus rhythm

  • • Sinus Pauses: Typically last < 3 seconds

    • Sinus Arrest: Typically last > 3 seconds

  • Not due to direct mechanical injury from the valve, but may occur in patients as a result of pre-existing disease or other external factors:

  • • Medications

    • • Beta blockers, calcium channel blockers, digoxin

    • Pre-existing damage to the SA node

    • • Fibrosis from a previous MI

Treatment

• If the patient is asymptomatic, provide ongoing surveillance

• If the patient is symptomatic, treatment should be aimed at the underlying cause:

• • For medication-induced abnormalities, stop the offending medication

  • For acute, unstable bradycardia:

  • • Medications: Atropine, Dopamine Infusion, Epinephrine Infusion

  • If cardiology is not immediately available, initiate transcutaneous pacing or insert a temporary transvenous pacemaker

  • Definitive treatment: Pacemaker

  • • ~10–15% of patients may develop a bradyarrhythmia post TAVR, with ~8-15% later requiring a pacemaker

Due to the risk of conduction abnormalities post TAVR, many patients are discharged with ambulatory rhythm monitoring such as a ZioPatch or Holter monitor, and may present to the emergency department for evaluation of rhythm disturbances.

References:

1. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay. Heart Rhythm. 2019;16(9):e128-e226.

2. Lilly, S, Deshmukh, A, Epstein, A. et al. 2020 ACC Expert Consensus Decision Pathway on Management of Conduction Disturbances in Patients Undergoing Transcatheter Aortic Valve Replacement: A Report of the American College of Cardiology Solution Set Oversight Committee. JACC. 2020 Nov, 76 (20) 2391–2411.

https://doi.org/10.1016/j.jacc.2020.08.050

1. Sammour, Y, Krishnaswamy, A, Kumar, A. et al. Incidence, Predictors, and Implications of Permanent Pacemaker Requirement After Transcatheter Aortic Valve Replacement. J Am Coll Cardiol Intv. 2021 Jan, 14 (2) 115–134.

https://doi.org/10.1016/j.jcin.2020.09.063

1. Tarakji KG, Patel D, Krishnaswamy A, et al. Bradyarrhythmias detected by extended rhythm recording in patients undergoing transcatheter aortic valve replacement (Brady-TAVR Study). Heart Rhythm. 2022;19(3):381-388.

Summarized by Ashley Lyons, OMS3 | Edited by Ashley Lyons & Ahmed Abdel-Hafiz, NREMT-P

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Contributor: Aaron Lessen, MD

Educational Pearls:

What are the common causes of agitation in the elderly?

• Baseline dementia causing a behavioral disturbance
• Delirium precipitated by an acute medical problem such as a UTI, pneumonia, overdose/side effect of home medications, urinary retention, constipation, pain, hypoxia, electrolyte abnormality, etc.
• Exacerbation of a primary psychotic condition such as schizophrenia or bipolar disorder.

What environmental changes can help reduce agitation?

• Maintain a quiet, calm, uncluttered environment
• Dim the lights
• Ensure the patient has their glasses, hearing aids, and dentures
• Avoid excessive lines such as foleys
• Minimize restraints and other forms of immobilization
• Reassure the patient frequently and have the family check in with the patient

What are the best options if medications are required?

• If the patient is unsafe or non-pharmacologic measures fail, consider a second-generation ("atypical") antipsychotic using the lowest effective dose:
  • Olanzapine
  • Risperidone
  • Quetiapine
• One special consideration is Dementia with Lewy Bodies, which can be very sensitive to antipsychotics.
  • In this case, Quetiapine is the preferred agent.

Avoid when possible:

• Diphenhydramine and other anticholinergics, which can worsen delirium (including urinary retention and sedation)
• Benzodiazepines, which may worsen confusion, falls, and respiratory depression
• Haloperidol, which has a higher risk of extrapyramidal symptoms and QT prolongation than many atypicals

References

1. Badwal K, Kiliaki SA, Dugani SB, Pagali SR. Psychosis Management in Lewy Body Dementia: A Comprehensive Clinical Approach. J Geriatr Psychiatry Neurol. 2022 May;35(3):255-261. doi: 10.1177/0891988720988916. Epub 2021 Jan 19. PMID: 33461372.
2. Kurlan R, Cummings J, Raman R, Thal L; Alzheimer's Disease Cooperative Study Group. Quetiapine for agitation or psychosis in patients with dementia and parkinsonism. Neurology. 2007 Apr 24;68(17):1356-63. doi: 10.1212/01.wnl.0000260060.60870.89. PMID: 17452579.
3. Shenvi C, Kennedy M, Austin CA, Wilson MP, Gerardi M, Schneider S. Managing Delirium and Agitation in the Older Emergency Department Patient: The ADEPT Tool. Ann Emerg Med. 2020 Feb;75(2):136-145. doi: 10.1016/j.annemergmed.2019.07.023. Epub 2019 Sep 26. PMID: 31563402; PMCID: PMC7945005.

Summarized and edited by Jeffrey Olson, MS4

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Contributor: Aaron Lessen, MD

Educational Pearls:

• Patients with pulmonary embolism (PE) are divided into three risk categories
  • Low risk (non-massive PE): patients are stable
    • Treatment: prescribe anticoagulants and discharge home
  • Intermediate risk (submassive PE): patients are stable but display evidence of clot burden such as elevated troponin, elevated BNP, and/or right heart strain
    • Treatment is controversial
  • High risk (massive PE): patients are unstable with hypotension, hypoxia, and/or respiratory distress
    • Treatment: IV thrombolysis to prevent decompensation
• A recent randomized controlled trial evaluated treatment of intermediate risk PE patients
  • Patients were randomized to receive either thrombectomy with anticoagulation or anticoagulation alone
  • The primary outcome evaluated changes in right ventricular enlargement at 48 hours
    • A controversial primary outcome because it does not speak to mortality or incidence of other necessary aggressive interventions
    • Low clinical significance
  • The study found that thrombectomy significantly reduced right ventricular enlargement faster than anticoagulation alone. However, there was no statistical difference in mortality or need for other treatments
• Treatment for intermediate risk PE patient remains controversial
• The same study will have second follow-up at 90 days to see if there are other benefits

References

1. Lookstein RA, Konstantinides SV, Weinberg I, Dohad SY, Rosol Z, Kopeć G, Moriarty JM, Parikh SA, Holden A, Channick RN, McDonald B, Nagarsheth KH, Yamada K, Rosovsky RP; STORM-PE Trial Investigators. Randomized Controlled Trial of Mechanical Thrombectomy With Anticoagulation Versus Anticoagulation Alone for Acute Intermediate-High Risk Pulmonary Embolism: Primary Outcomes From the STORM-PE Trial. Circulation. 2026 Jan 6;153(1):21-34. doi: 10.1161/CIRCULATIONAHA.125.077232. Epub 2025 Nov 3. PMID: 41183181.

Summarized by Meg Joyce, MS2 | Edited by Meg Joyce & Jorge Chalit, OMS4

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