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“This learning material is sourced from Emergency Medicine Cases [with link to emergencymedicinecases.com] and has been published here with permission as per creative commons copyright”
Topics in this EM Quick Hits podcast
Justin Hensley & Aaron Billin on wilderness medicine (0:38)
Elisha Targonsky on bowel prep hyponatremia (Best of University of Toronto EM) (14:23)
Brit Long on identification of non-convulsive status epilepticus (21:18)
Andrew Petrosoniak on Morel Lavallee lesions (29:24)
Jess McLaren on approach to the ECG in the paced patient (36:35)
Matt Poyner on loan repayment vs investing (41:22)
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 February 14, 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
- Risk factors:
- Large volume intake over short time
- More frequent in women
- Concomitant use of thiazide diuretics
- Concomitant hypothyroidism
- 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.
Episode 60 Emergency Management of Hyponatremia
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
- Causes:
- Most common: inadequately treated convulsive status epilepticus
- Acute brain injury
- Structural brain lesion
- Infection
- Encephalopathy
- Chronic alcohol use
- Medications
- 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
Best Case Ever 22 Non-Convulsive Status Epilepticus
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.
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?
For ECG examples and deep dive… ECG Cases 36 – PACER mnemonic for Approach to Pacemaker Patients
