Podcast production, editing and sound design by Anton Helman
Written summary & blog post by Hanna Jalali, Andrew Petrosoniak and Brit Long.
Edited by Anton Helman, February 2023
Cite this podcast as: Helman, A. Hensley, J. Billin, A. Targonsky, E. Long, B. Petrosoniak, A. McLaren, J. Poyner, M. EM Quick Hits 46 – Wilderness Medicine, Bowel Prep Hyponatremia, Non-Convulsive Status Epilepticus, Morel Lavallee Lesions, Pacemaker ECGs, Loans vs Investing. Emergency Medicine Cases. February, 2023. https://emergencymedicinecases.com/em-quick-hits-february-2023/. Accessed December 7, 2023.
Bowel prep hyponatremia
Best of University of Toronto EM
Severe hyponatremia causing coma and/or seizure after bowel prep such as polyethylene glycol for colonoscopy has been reported in the literature.
The incident of hyponatremia and elevated ADH levels is up to 7.5% in patients post-colonoscopy.
Causes are multifactorial:
Stress from procedure/prep causing non-osmotic ADH release, water retention
GI volume losses
Dietary restriction, low solute intake
Massive free water intake, dilutional hyponatremia
Large volume intake over short time
More frequent in women
Concomitant use of thiazide diuretics
Treatment of severe hyponatremia with coma/seizure includes hypertonic saline, given as a bolus of 100-150mL of fluid over 5-10 minutes (repeat x 1-2 prn), stopping all other IV fluids, insertion of foley catheter to monitor urine output, frequent checks of serum electrolytes being careful not to increase serum sodium by more than 6mmol/L over 6 hours for severely symptomatic patients and aiming to increase sodium by 4-6mmol/L over first 2 hours, and no more than 10mmol/L over 24 hours
Resist treatment in patients with mildly impaired mental status, or chronic hyponatremia as rapid correction can lead to osmotic demyelination syndrome.
Adrogué HJ, Tucker BM, Madias NE. Diagnosis and Management of Hyponatremia: A Review. JAMA. 2022 Jul 19;328(3):280-291.
Windpessl, M., Schwarz, C. & Wallner, M. “Bowel prep hyponatremia“ – a state of acute water intoxication facilitated by low dietary solute intake: case report and literature review. BMC Nephrol 18, 54 (2017).
Reumkens A, van der Zander Q, Winkens B, Bogie R, Bakker CM, Sanduleanu S, Masclee AAM. Electrolyte disturbances after bowel preparation for colonoscopy: Systematic review and meta-analysis. Dig Endosc. 2022 Jul;34(5):913-926.
Costelha J, Dias R, Teixeira C, Aragão I. Hyponatremic Coma after Bowel Preparation. Eur J Case Rep Intern Med. 2019 Aug 26;6(9):001217.
Rasheed T, Alvi H, Shaikh MA, Ali FS, Zuberi BF, Subhan W. Frequency of hyponatremia caused by sodium picosulfate solution when used as a bowel cleansing agent for colonoscopy. Pak J Med Sci. 2020 Nov-Dec;36(7):1651-1654.
Non-Convulsive Status Epilepticus
Non-convulsive status epilepticus (NCSE) is a change in cognition or mental status with no significant convulsive activity and accounts for 47% of all status epilepticus.
EEG definition of NCSE is abnormalities on EEG for 10 continuous minutes or intermittent seizure activity for >20% of an hour
It is important have NCSE on our differential for alteration in mental status and treat appropriately if suspected.
Consider NCSE in patients with:
altered mental status and abnormal ocular movements, lip smacking or subtle muscle twitches
medication history with anti-epileptic
patients that were seizing, treated, and are having a prolonged post-ictal period
unexplained altered mental status with no findings on ED testing
Most common: inadequately treated convulsive status epilepticus
Acute brain injury
Structural brain lesion
Chronic alcohol use
Presentation *a careful ocular exam showing subtle abnormalities is often the clue to NCSE
Most common: change in mental status
Abnormality in ocular movement (i.e. eye deviation, nystagmus, eyelid twitching. Specificity of altered mental status and ocular movement abnormality is 85% for NCSE).
Changes in speech (aphasia): occurs in 15% of cases
Motor twitching of face or hands (e.g. lip smacking)
Other findings: hypertension, diaphoresis, flushing, catatonia, repeated crying or laughing
Key ED diagnostic clue: a trial of benzodiazepines with an improvement in LOA is suggestive of NCSE
Trinka E, Cock H, Hesdorffer D, et al. A definition and classification of status epilepticus—report of the ILAE Task Force on Classification of Status Epilepticus. Epilepsia. 2015;56:1515-1523.
Hirsch LJ, Fong MWK, Leitinger M, et al. American clinical neurophysiology society’s standardized critical care EEG terminology: 2021 version. J Clin Neurophysiol. 2021;38:1-29.
Leitinger M, Beniczky S, Rohracher A, et al. Salzburg consensus criteria for non-convulsive status epilepticus—approach to clinical application. Epilepsy Behav. 2015;49:158-163.
Wang X, Yang F, Chen B, Jiang W. Non-convulsive seizures and non-convulsive status epilepticus in neuro-intensive care unit. Acta Neurol Scand. 2022 Dec;146(6):752-760.
Kinney MO, Craig JJ, Kaplan PW. Non-convulsive status epilepticus: mimics and chameleons. Pract Neurol. 2018 Aug;18(4):291-305.
Bravo P, Vaddiparti A, Hirsch LJ. Pharmacotherapy for nonconvulsive seizures and nonconvulsive status epilepticus. Drugs. 2021;81:749-770.
Morel Lavallee Lesions – closed de-gloving injury of the pelvis or leg
Morel Lavallee lesions are uncommon closed de-gloving injury of the pelvis or leg that is usually caused by high-energy trauma to the soft tissues resulting in detachment of the subcutaneous tissues from the deep fascia that typically present hours to days to weeks following high energy trauma
Diagnosis is typically suspected clinically but confirmed using one of U/S, CT or MRI
Clinical findings include fluctuant mass, edema, and tenderness at affected site with possibility of overlying cellulitis from initial dermal injury
Missed diagnosis may result in pressure necrosis, compartment syndrome, infection (including necrotizing fasciitis), chronic collections
Management ranges from conservative treatment with compression to minimally invasive to an open surgical approach.
Ten-year incidence and treatment outcomes of closed degloving injuries (Morel-Lavallee lesions) in a level 1 trauma centre. J Med Imaging Radiat Oncol 2022 Jul 29.
Practical Review of the Comprehensive Management of Morel-Lavallée Lesions. Plast Reconstr Surg Glob Open. 2021 Oct 7;9(10):e3850.
Morel-Lavallée Lesions: A Diagnostic and Clinical Dilemma. 2022 Aug 15;14(8):e28038.
Approach to pacemaker ECGs – the PACER mnemonic
P: Pacemaker spikes – are they present and appropriate?
Normal pacemaker spikes can be appropriately absent with normal intrinsic rhythm or appropriately present either intermittently or with full pacing.
A: awareness. Is the pacemaker aware of the intrinsic rhythm?
Normal pacemaker will sense intrinsic rhythm and inhibit pacing or will sense lack of intrinsic rhythm and deliver appropriate pacing.
Abnormalities are oversensing (responding to stimuli other than intrinsic rhythm). This leads to Another abnormality may be undersensing (not recognizing intrinsic rhythm). This leads to overpacing.
C: capture. Do pacemaker spikes trigger appropriate depolarization?
In normal capture every spike triggers a beat, in failure to capture pacing spikes fails to trigger a beat
E: ECG. Does the rest of the 12-lead ECG reveal any other problems?
Is there evidence of further QRS widening due to hyperkalemia which can lead to pacemaker malfunction?
OMI can be identified using the Modified Sgarbossa criteria. This include concordant ST elevation, concordant ST depression in anterior leads, or discordance defined as ST elevation >25% of preceding S wave.
R: rest of patient. Are their complications from pacemaker insertion, or emergencies unrelated to the pacemaker?
Glikson M, Nilsen JC, Kronbord MB, et al. 2021 ESC guidelines on cardiac pacing and cardiac resynchronization therapy: developed by the Task Force on cardiac pacing and cardiac resynchronization therapy of the European Society of Cardiology (ESC) with the special contribution of the European Heart Rhythm Association (EHRA). Eur Heart J Sept 2021;42(35):3427-3520
Cardall TY, Chan TC, Brady WJ, et al. Permanent cardiac pacemakers: issues relevant to the emerg physician, part I. J of Emerg Med 1999;17(3):479-489
Cardall TY, Brady WJ, Chan TC et al. Permanent cardiac pacemakers: issues relevant to the emerg physician, part II. J of Emerg Med 1999;17(4):697-709
Barold SS, Herweg B. The effect of hyperkalemia on cardiac rhythm devices. Europace 2014;16:467-476
Dodd KW, Zvosec DL, Hart MA, et al. Electrocardiographic diagnosis of acute coronary occlusion myocardial infarction in ventricular paced rhythm using the Modified Sgarbossa Criteria. Ann Emerg Med 2021 Oct;78(4):517-529
Gunaseelan R, Sasikumar M, Aswin K, et al. Memory T-waves, a rare cause of T-wave inversion in the emergency department. J Emerg Trauma Shock 2020 Oct-Dec;13(4):312-316
None of the authors have any conflicts of interest to declare
Dr. Anton Helman is an Emergency Physician at North York General in Toronto. He is an Assistant Professor at the University of Toronto, Division of Emergency Medicine and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Instititute. He is the founder, editor-in-chief and host of Emergency Medicine Cases.